Symposium Organizers
Li-Chyong Chen National Taiwan University
John Robertson Cambridge University
Zhong Lin Wang Georgia Institute of Technology
David B. Geohegan Oak Ridge National Laboratory
P1:Growth
Session Chairs
Li-Chyong Chen
David Geohegan
John Robertson
Zhong Lin Wang
Tuesday PM, March 25, 2008
Room 3003 (Moscone West)
9:15 AM - **P1.1
Kinetic modeling of Single-Walled Carbon Nanotube growth on Co-Mo/SiO2 catalysts with same-particle characterization of catalysts and product.
Daniel Resasco 1
1 , University of Oklahoma, Norman, Oklahoma, United States
Show Abstract9:45 AM - P1.2
Pressure-Induced Single-Walled Carbon Nanotube (n,m) Selectivity on Co-Mo Catalysts.
Yuan Chen 1 , Bo Wang 1 , Li Wei 1
1 School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore Singapore
Show AbstractSingle walled carbon nanotubes (SWCNTs) were synthesized using four different carbon precursors including CO, C2H5OH, CH3OH, and C2H2 on Co-Mo catalysts. Semiconducting (n,m) abundance was evaluated by a method based on a single-particle tight-binding theoretical model taking into consideration the relative photoluminescence and absorption quantum efficiency for specific (n,m) tubes. (n,m) abundance determined in photoluminescence analysis was used to reconstruct the near-infrared Es11 absorption spectra. Carbon precursor pressure was found to be the key factor to the chirality control in this study. Narrowly (n,m) distributed SWCNTs can only be obtained under high-pressure CO or vacuumed C2H5OH and CH3-OH. The majority of these nanotubes are predominately in the same higher chiral-angle region. The carbon precursor chemistry may also play an important role to obtain narrowly (n,m) distributed SWCNTs. (n,m) selectivity on Co-Mo catalysts shifts under different carbon precursors providing the route for (n,m) specific SWCNTs production. We further found the selective growth of bulk single-walled carbon nanotube (SWCNT) samples enriched with three different dominant chiralities including (6,5), (7,5), and (7,6) through adjusting the pressure of carbon monoxide on Co-Mo catalysts from 2 to 18 bar. Results indicate that the abundance of each chiral tube can be systematically altered by changing the carbon monoxide pressure.Reference:J. Am. Chem. Soc. 2007, 129, 9014-9019J. Phys. Chem. C, Vol. 111, No. 40, 2007 14612-14616
10:00 AM - P1.3
Proper Combination of Catalyst Materials and Ethanol for High Yield in CVD Growth of Carbon Nanotubes.
Fumihiko Maeda 1 2 , Yoshihiro Kobayashi 1 2
1 NTT Basic Research Laboratories, Nippon Telegraph and Telephone corporation, Atsugi-shi, Kanagawa, Japan, 2 , CREST, JST, Atsugi-shi, Kanagawa, Japan
Show Abstract10:15 AM - P1.4
Real-Time Monitoring Coupled with Combinatorial Catalyst Library for Millimeter Growth of Single-Walled Carbon Nanotubes.
Suguru Noda 1 , Kei Hasegawa 1 , Hisashi Sugime 1 , Shigeo Maruyama 2 , Yukio Yamaguchi 1
1 Department of Chemical System Engineering, The University of Tokyo, Tokyo Japan, 2 Department of Mechanical Engineering, The University of Tokyo, Tokyo Japan
Show AbstractThe growth rate and the catalyst lifetime govern the yield of single-walled carbon nanotubes (SWNTs) by chemical vapor deposition (CVD) using supported catalysts. However, the large number of process parameters and the relatively poor reproducibility of the SWNTs growth made it difficult to derive these values separately and systematically. Recent progress in the synthesis method realized the millimeter growth of SWNTs [1], which can be monitored even by naked eyes. We also realized the millimeter growth of SWNTs [2] by the aid of our combinatorial method [3]. In this work, we coupled a real-time monitoring with our combinatorial catalyst library and obtained both the growth rate and the catalyst lifetime for a series of catalyst particles in a single experimental run. We newly designed and made a simple reactor; an externally heated, quartz glass tubular reactor with a window at one end of the tube. Through this window, substrates can be observed by a digital camera in situ during CVD. A combinatorial catalyst library with a gradient thickness profile of catalyst was placed in the reactor, and the growing SWNTs from the whole catalyst thickness region was observed perpendicular to the thickness profile. By this method, we found that the narrow window of millimeter growth of SWNTs arises from the catalyst lifetime rather than the growth rate. In CVD from C2H4/H2/Ar gas with Fe/Al2O3 catalyst, the catalytic role of Al2O3 support proved essential for the millimeter growth, and a small addition of water proved not to enhance the growth rate but to widen the catalyst window for a long lifetime. Efficient optimization by this method enabled us to realize water-free growth of millimeter tall SWNT forests by a simple reactor which does not have any vacuum pumps. Millimeter growth of SWNTs was achieved also from an ethanol feedstock. This simple method will accelerate both basics and applications of catalytic growth of SWNTs. [1] K. Hata, et al., Science 306, 1362 (2004). [2] S. Noda, et al., Jpn. J. Appl. Phys. 46, L399 (2007). [3] S. Noda, et al., Carbon 44, 1414 (2006).
10:30 AM - P1.5
In situ Transient Growth Kinetics of Vertically-Aligned Carbon Nanotube Arrays at Low-Pressures.
Jeremy Jackson 1 , Alex Puretzky 2 , Gyula Eres 1 , Chris Rouleau 2 , Hui Hu 1 , Bin Zhao 2 , David Geohegan 2
1 Material Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States, 2 Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States
Show Abstract10:45 AM - P1.6
In-situ Time-resolved XPS Study of Catalyst Behavior During Carbon Nanotube Growth.
C. Wirth 1 , Stephan Hofmann 1 , John Robertson 1 , C. Mattevi 2 , C. Cepek 3 , A. Goldoni 4 , M. Cantoro 1 , R. Blume 5 , D. Teschner 5 , S. Zafreiratos 5 , P. Schnoerch 5 , A. Oesterriech 5 , M. Haevecker 5 , R. Schlogl 5
1 Engineering Dept, Cambridge University, Cambridge United Kingdom, 2 , University of Padova, Padova Italy, 3 , Lab Nazionale, Trieste Italy, 4 , Sincrotrone, Trieste Italy, 5 , Fritz Haber Institute, Berlin Germany
Show Abstract11:30 AM - **P1.7
The Role of Autocatalytic Kinetics in Rapid Growth of Vertically Aligned Nanotube Arrays.
Gyula Eres 1 , C. Rouleau 1 , A. Puretzky 1 , J. Jackson 1 , D. Geohegan 1
1 , Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States
Show AbstractSince 1995 when the first papers on chemical vapor deposition (CVD) of carbon nanotubes appeared, more than 3000 papers have been published on the topic. A closer look shows that only about 2% of these papers deal with growth kinetics, explaining at least part of the reason for the presently poor understanding of the growth process. An intriguing feature of the CVD process common to several experiments that reported time-dependent yield or growth rate measurements is that a disproportionately large fraction (in some cases more than 50%) of the growth occurs very fast, during the first few minutes of the process. After the initial rapid growth stage the growth slows down significantly and decelerates over a much longer time period to eventually stop. In this talk I will describe real-time measurements of the growth rate of vertically aligned nanotube arrays (VANTA) and explore the mechanisms that are compatible with this kinetic behavior. In addition to having great practical significance, the self-organized form of directionally aligned CNT growth in VANTAs facilitates real-time studies of growth kinetics by in situ measurements of the height of growing arrays. A particularly intriguing feature of VANTA growth by CVD is the transient nature of the process. The growth rate changes throughout the process without ever settling at a fixed level. In addition to the decelerating growth stage, the real-time data reveal two additional features of the growth kinetics. The onset of growth is preceded by an incubation period characterized by the onset of growth acceleration. In the next stage growth keeps accelerating until it reaches a peak and turns over. These additional two growth stages combined with the decelerating stage form an S-shaped growth curve. In the past few years a number of reports described a beneficial effect from the addition of water and oxygen species, and even CNT growth from non-transition metals. These observations are difficult to explain in the context of the conventional view and cast doubt on the general validity of the diffusion-precipitation model. The S-shape growth behavior is a characteristic signature of a specific kinetics known as autocatalysis that is often observed in carbon network formation including polymerization and soot growth in connection with acetylene pyrolysis. The polymerization reaction is triggered by “initiators” like water and oxygen containing species that are known to produce carbon containing free radicals. The main significance of the concept of polymerization in nanotube synthesis is that it offers new approaches for controlling the nanotube structure at the level of carbon-carbon bond formation by applying the well established methodologies of organic and polymer chemistry.
12:00 PM - P1.8
Growth of Carbon Nanotubes for CMOS Interconnects.
Guofang Zhong 1 , John Robertson 1
1 Engineering Dept, Cambridge University, Cambridge United Kingdom
Show Abstract12:15 PM - P1.9
CMOS Compatible Synthesis of Carbon Nanotubes.
G. Ayre 1 , T. Uchino 3 , B. Mazumder 2 , D. Smith 1 , A. Hector 2 , C. de Groot 3 , P. Ashburn 3
1 School of Physics and Astronomy, University of Southampton, Southampton, Hampshire, United Kingdom, 3 School of Electronics and Computer Science, University of Southampton, Southampton, Hampshire, United Kingdom, 2 School of Chemistry, University of Southampton, Southampton, Hampshire, United Kingdom
Show AbstractTraditionally, carbon nanotube (CNT) growth involves the use of transition metal nanoparticles as a catalyst. However, the integration of CNT synthesis based on metal catalysts with CMOS technology is very problematic due to the detrimental effect of transition metals on silicon device performance. Transition metals, such as Ni or Fe, create deep level defects in the silicon band gap and result in unwanted trap states [1, 2]. Other drawbacks include the high propensity of silicon-metal inter-diffusion, leading to the formation of silicides. In order to reap the benefits of silicon very-large-integration (VLSI) technology, an alternate approach is required.This work reports metal free-growth of carbon nanotubes, with a process compatible with current silicon VLSI technology, using chemical vapour deposition on germanium nanoparticles. Various approaches to germanium catalyst preparation, based upon standard CMOS processes, are compared in terms of density of growth and quality of synthesized nanotubes. These approaches include thermal treatment of silicon-germanium islands [3] and germanium Stranski-Krastanow quantum dots, germanium colloidal nanoparticles and germanium nanoparticles formed by ion implantation.Scanning electron microscopy measurements indicate that a good density of growth is achievable using this methodology. Raman measurements have identified the synthesized nanotubes as single walled and, in terms of graphitisation and structure, of a high quality. Extensive atomic force microscopy characterisation of the catalyst has been undertaken in order to ascertain the influence of morphology on the ability of germanium to catalyse CNT growth.Experimental evidence has shown that this technique offers a commercially scalable method of reliably growing metal-free CNTs for various applications, while opening the prospect of merging CNT devices with silicon electronics.References [1]Y. Tiaan et al, “Electrically Active Defects in Ni-Si Silicide Studied by Deep Level Transient Spectroscopy,” Semicond. Sci. Technol., vol. 17, no. 1, p. 86, 2002[2]S. Naito and T. Nakashizu, “Electric Degradation and Defect Formation of Silicon due to Cu, Fe and Ni Contamination,” Proc. Mat. Res. Soc., vol. Defect Eng. Semiconductor Growth, p. 641, 1992[3]T. Uchino, K. N. Bourdakos, C. H. de Groot, P. Ashburn, M. E. Kiziroglou, G. D. Dilliway and D. C. Smith, “Metal Catalyst-free Low Temperature Carbon Nanotube Growth on SiGe Islands,” Appl. Phys. Lett., vol. 86, p. 233110, 2005
12:30 PM - P1.10
Full Scale Wafer Growth of Perfectly Aligned Carbon Nanotubes and Aligned Growth Characterization.
Deji Akinwande 1 , Nishant Patil 1 , Albert Lin 1 , Yoshio Nishi 1 , H.-S Philip Wong 1
1 , Stanford University, Stanford, California, United States
Show Abstract12:45 PM - P1.11
Wafer-scale Fabrication of a Vertically-aligned NEMS Switch Based on Carbon Nanofibers.
Dmitry Kozak 1 2 , Joel Kubby 1 , Alan Cassell 2 , Brett Cruden 2
1 EE, UCSC, Santa Cruz, California, United States, 2 , NASA AMES, Moffet Field, California, United States
Show AbstractP4: Poster Session: CNTs Growth
Session Chairs
Wednesday AM, March 26, 2008
Salon Level (Marriott)
9:00 PM - P4.1
Chirality Sorted Nanotubes Extracted for Electronic Devices.
Soumendra Barman 1 , Melburne LeMieux 1 , Zhenan Bao 1
1 Department of Chemical Engineering, Stanford University, Stanford, California, United States
Show AbstractCarbon nanotubes (CNTs) possess great potential to be the next breakthrough active element for sensors, flexible computing networks and next generation electronics. The manufacture of CNTs involves the decomposition of carbon into graphitic tubes of different diameters and chiralities. However, CNTs have a huge processing drawback. Depending on the chirality of the nanotube, it behaves as a semiconductor or a metal and one of the greatest obstacles for creating the next generation of devices is the separation of nanotubes by chirality. Here, we present a process for the distinct sorting of single wall CNTs via the ultracentrifugation method (e.g. Hersam et al), and a novel high-yield process of collecting the sorted bands. In addition, we demonstrate this via u-Raman measurements and electronic device properties. Our aim is to scale up this sorting in order to fabricate wafer scale devices and refine the separation for highly selective sensor applications without polymer wrapping, which impedes sensor and device performance. Indeed, the fabrication of sensors and of high performance SWNT thin film transistors (TFTs) using single walled carbon nanotubes of a single chirality will dramatically increase their performance, as well as increasing reliability and uniformity.
9:00 PM - P4.10
Investigation of Electrophoretic Deposited CNT Cathode for Micro-Focus Field Emission X-Ray Source.
Xiomara Calderon-Colon 1 , Otto Zhou 1 2 3
1 Curriculum in Applied and Materials Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States, 2 Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States, 3 Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
Show Abstract9:00 PM - P4.11
Large Scale Synthesis of Vertical Aligned CNT Array on the Quartz Particle.
Qiang Zhang 1 , Jia-Qi Huang 1 , Meng-Qiang Zhao 1 , Wei-Zhong Qian 1 , Yao Wang 1 , De-Zheng Wang 1 , Fei Wei 1
1 Department of Chemical Engineering,Tsinghua University , Beijing Key laboratory of Green Reaction Engineering and Technology,Department of Chemical Engineering,Tsinghua University , Beijing, Beijing, China
Show Abstract9:00 PM - P4.12
Catalytic CVD Synthesis of the Single-walled BN and BxCyNz Nanotubes and Related Studies.
Wenlong Wang 1 2 , Yoshio Bondo 1 , Enge Wang 2 , Dmitri Golberg 1
1 International Center for Young Scientists (ICYS), National Institute for Materials Science, Tsukuba Japan, 2 Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing China
Show Abstract9:00 PM - P4.13
Controlled Alignment of Single-wall Carbon Nanotubes for Advanced Composites.
Hubert Phillips 1 , Laura Pena-Paras 1 , Dario Prieto-Centurion 1 , Howard Schmidt 2 , Enrique Barrera 1
1 MEMS, RICE University, Houston, Texas, United States, 2 Chemistry, RICE University, Houston, Texas, United States
Show Abstract9:00 PM - P4.14
Aligned Single Walled Carbon Nanotube Patterns for Field Effect Transistors: Fabrication and Electrical Characterization.
Dae Il Kim 1 , Yong Kwan Kim 1 , Jaehyun Park 1 , Gunchul Shin 1 , Gyu-Tae Kim 2 , Jeong Sook Ha 1
1 Department of Chemical and Biological Engineering , Korea University, Seoul Korea (the Republic of), 2 School of Electrical Engineering, Korea University, Seoul Korea (the Republic of)
Show Abstract9:00 PM - P4.15
Study of Formation of Well Crystalline Carbon Nanotubes During High-Energy Milling of Lead Magnesium Niobates.
Elena Tchernychova 1 , Danjela Kuscer 1 , Marija Kosec 1
1 Electronic Ceramics Department, Jozef Stefan Institute, Ljubljana Slovenia
Show Abstract9:00 PM - P4.17
The Effect of NiCr Grain Boundary Segregation on the Direct Growth of Carbon Nanotubes and Enhanced Field Emission Properties.
Setha Yim 1 2 , Riichiro Ohta 3 , Nathaniel Zuckerman 1 4 , Jessica Killian 1 4 , Chuck Hitzman 5 , Emily Allen 2 , Meyya Meyyappan 6 , Cattien Nguyen 1
1 Ames Center for Nanotechnology, ELORET/NASA Ames Research Center, Moffett Field, California, United States, 2 Department of Chemical and Materials Engineering, San Jose State University, San Jose, California, United States, 3 University Affiliated Research Center, University of California, Santa Cruz, NASA Ames Research Park, Moffett Field, California, United States, 4 Department of Chemistry, San Jose State University, San Jose, California, United States, 5 Stanford Nanocharacterization Laboratory, Stanford University, Stanford, California, United States, 6 Ames Center for Nanotechnology, NASA Ames Research Center, Moffett Field, California, United States
Show Abstract9:00 PM - P4.18
Synthesis and Characterization of Stoichiometric Boron Nitride Nanostructures.
Jose Nocua 1 , Gerardo Morell 1 2
1 Departmet of physic, University of Puerto Rico, Rio Piedras, Puerto Rico, United States, 2 Department of Physic, Institute for Functional Nanomaterials, Rio Piedras, Puerto Rico, United States
Show Abstract9:00 PM - P4.19
Growth of the BN – Nano - Structured Materials using Borazine Decomposition by Laser Chemical Vapor Synthesis.
Arturo Hidalgo 1 , Vladimir Makarov 1 , Gerardo Morell 1
1 , University of Puerto Rico, Carolina, Puerto Rico, United States
Show Abstract9:00 PM - P4.2
Novel Fabrication of Single Walled Carbon Nanotubes and Direct Testing of Their Structural and Electronic Properties.
Jianfeng Wu 1 , Devon McClain 1 , Timothy Gutu 1 , Jun Jiao 1 , Seongmin Kim 2 , Mark Mann 2 , Yan Zhang 2 , Kenneth Teo 2
1 Department of Physics, Portland State University, Portland, Oregon, United States, 2 Department of Engineering, University of Cambridge, Cambridge United Kingdom
Show AbstractFabricating horizontally aligned single wall carbon nanotubes (CNTs) with controlled properties has been one of the significant challenges for field-effect transistor (FET) applications. The most common method for fabricating a CNT FET begins with the sonicated dispersion of existing CNTs, followed by the distribution of the CNTs onto a substrate with predefined electrodes. However, contact resistance in particular, has frequently interfered with tests performed in the traditional dispersion and alignment methods. This report demonstrates a novel procedure for the fabrication of horizontally aligned single walled CNTs by using the focused ion beam and chemical vapor deposition. This method allows the morphologies, internal structures, and elemental compositions of CNTs to be directly analyzed in the scanning electron microscope and transmission electron microscope, while avoiding any sample preparation procedures that might alter the structure of the CNTs. After fabrication, electrodes are deposited at the two ends of CNTs to allow electronic properties, including contact resistance, to be tested. In this study, the electronic properties of direct-grown horizontally aligned single walled CNTs are compared with those of dispersed and aligned single walled CNTs. It is expected that the testing CNT/electrode structures prepared by this novel procedure will exhibit minimized substrate-to-CNT contact resistance (typically on the order of kilohms or megaohms). The promising characterization results suggest that the methodology introduced here will likely open new opportunities for the direct fabrication of CNT based nanodevices.
9:00 PM - P4.20
Water-Soluble Non-HiPCo Single-walled Nanotubes Prepared From The Two-Step Phenylation-Sulfonation Reactions.
Wendy Fan 1 , Tane Boghozian 1 , Cruden Brett 2 , Mairead Stackpoole 1 , James Arnold 2 , Sylvia Johnson 3
1 , Eloret Corp., Sunnyvale, California, United States, 2 , UCSC-NASA Ames, Moffett Field, California, United States, 3 Thermal protection Materials Branch, NASA Ames Research Center, Moffett Field, California, United States
Show Abstract9:00 PM - P4.21
Oriented MWCNT Forest Growth for Tunable Dry-draw Self Assembly into Nanotube Sheets and Yarns.
Raquel Ovalle Robles 1 3 , Xavier Lepro 4 3 , Alexander Kuznetsov 1 3 , Shaoli Fang 3 , Ray Baughman 2 3 , Anvar Zakhidov 1 3
1 Physics , University of Texas at Dallas (UT-D), Richardson, Texas, United States, 3 NanoTech Insitute, University of Texas at Dallas (UT-D), Richardson, Texas, United States, 4 Material Science, University of Texas at Dallas (UT-D), Richardson, Texas, United States, 2 Chemestry, University of Texas at Dallas (UT-D), Richardson, Texas, United States
Show AbstractThe dry-draw of Multi Wall Carbon Nanotube (MWCT) forest is a very powerful method to create macro scale yarns and transparent nanotube sheets in a highly efficiently, easy and scalable way [1,2]. However, as originally developed for CVD grown forests of certain density and height ranges, this process did not allowed to control the properties of CNT sheets, e.g. to tune optical transparency and/or sheet resistance among others. Recently, it has been realized that, the key parameters to control the ability to dry-draw the sheets from the CNT forest are the density and the topology of the bundle interconnections of the forests. These interconnections are determined by a range of heights from drawable forests [3]. In this presentation we show that as a result of controlling the thickness, uniformity and morphology of the Fe catalyst layer by fine tuned e-beam deposition we are able to grow forest with lower height and higher density of interconnects between bundles that allows us to draw CNT sheets from shorter forests. We are also able to dry draw sheets in a tunable way in correspondence with a recently developed model of self-assembly by interconnected bundle reorientation [3]. [1] M. Zhang, S. Fang, A. Zakhidov, S. Lee, C. Williams, R. Baughman, Science 309, 1215 (2005).[2] M. Zhang, K. R. Atkinson, R. H. Baughman, Science 306, 1358 (2004) [3] A. Kuznetsov, A. Zakhidov, et.al., submitted MRS 2008 Spring Meeting
9:00 PM - P4.22
Carbon Metal Interactions and Epitaxy in Nanotube Growth: Towards Chirality-selected Nanotube Production.
Feng Ding 1 , Peter Larsson 3 , Andreas Larsson 4 , Rajeev Ahuja 3 , Kim Bolton 2 , Arne Rosen 2 , Boris Yakobson 1
1 ME&MS, Rice University, Houston, Texas, United States, 3 Department of Physics, Uppsala University, Uppsala Sweden, 4 Tyndall National Institute, University College Cork, Cork Ireland, 2 Physics Department, Göteborg University, Göteborg Sweden
Show Abstract9:00 PM - P4.24
Synthesis of Aligned Single Walled Carbon Nanotubes using Fe Catalysts Defined by Nanosphere Lithography.
Alexander Badmaev 1 , Koungmin Ryu 1 , Lewis Gomez 1 , Fumiaki Ishikawa 1 , Chongwu Zhou 1
1 Electrical Engineering, University of Southern California, LA, California, United States
Show Abstract9:00 PM - P4.25
Combinatorial Exploration of CNT Growth Using Composition Gradients.
Jonathan Petrie 1 , Benjamin Hertzberg 1 , Robert van Dover 1
1 , Cornell University, Ithaca, California, United States
Show Abstract9:00 PM - P4.26
Crucial Role of Ethylene Pyrolysis in Millimeter Growth of Single-walled Carbon Nanotubes as Evidenced by Separate Optimization of Gas and Catalyst Temperatures.
Ryuhei Ito 1 , Suguru Noda 1 , Toshio Osawa 1 , Shigeo Maruyama 2 , Yukio Yamaguchi 1
1 Department of Chemical System Engineering, The University of Tokyo, Tokyo Japan, 2 Department of Mechanical Engineering, The University of Tokyo, Tokyo Japan
Show Abstract9:00 PM - P4.27
WITHDRAWN 02/21/08 The Size Effect of Cobalt Catalyst on Carbon Nanotube Growth in a Confined Space.
Fu-Ming Pan 1 , Chen-Chun Lin 1 , Kai-Chun Chang 1 , Cheng-Wen Kuo 1 , Cheng-Tzu Kuo 1
1 , National Chiao Tung University, Hsinchu Taiwan
Show AbstractTuesday, March 25WithdrawnPosterP4.27
9:00 PM - P4.28
Effect of Barrier Layers on Patterned Vertically-Aligned Carbon Nanotube Growth.
Brendan Turner 1 , David Hutchison 1 , Richard Vanfleet 1 , Robert Davis 1
1 Physics and Astronomy, Brigham Young University, Provo, Utah, United States
Show Abstract9:00 PM - P4.3
New Strategy to Fabricate Highly Conductive Materials with Length Controlled CNTs.
Hyunjung Lee 1 , Hye Park 1 , Kyung-A Oh 1 , Min Park 1
1 Hybrid Materials Research Center, KIST, Seoul Korea (the Republic of)
Show Abstract9:00 PM - P4.4
Synthesis and Characterization of Thin-multiwalled Carbon Nanotubes and their Field Emission Properties.
Dong Hoon Shin 1 , Ji Hoon Choi 1 , Sang Min Park 1 , Cheol Jin Lee 1
1 School of Electrical Engineering, Korea University, Seoul, Seoul, Korea (the Republic of)
Show AbstractWe have synthesized the thin multiwalled carbon nanotubes (t-MWCNTs) using a catalytic chemical vapor deposition method. To synthesize the t-MWCNTs, we used gas phase methane carbon source and Fe-Mo/MgO catalyst which produced by gel-combustion method. The Gel-combustion method has many advantages to get a uniform distribution of metal particle size over the support material. The catalyst was prepared by a gel-combustion technique using MgO as a catalyst support. The Fe-Mo/MgO catalyst was prepared according to the following procedure. A mixture of Fe(NO3)3.9H2O, Mg(NO3)2.4H2O and citric acid was dissolved in DI water, followed by the addition of Mo source. After stirring the heterogeneous mixture at room temperature for 30 min, the solution was dried. The solid material was then ground in a mortar into fine powder and calcined in a quartz furnace at 700C for 2 hr. In our experiment, we used the various Mo mole fractions (0.025, 0.05 and 0.075) at fixed Fe0.1 MgO0.875 as the three kinds of catalyst composition to get the high-yield homogeneous t-MWCNTs. An amount of 0.1 g of the catalyst was put into a quartz boat at the center of the reactor tube. Once the temperature reached at 900C, we supplied the mixture gas of Ar/CH4/H2 (1000/1000/200sccm) for 30 min in order to synthesize t-MWCNTs. Finally, the reactor was cooled to room temperature in Ar (500sccm) ambient. The morphologies and microstructures of the as-synthesized t-MWCNTs were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The product was further characterized by Thermogravimetric analyzer (TGA) and Raman spectroscopy. As-synthesized thin MWCNTs have a narrow diameter in the range from 5 to 7 nm. Graphene layers have range about 3-5 numbers. According to the analysis of thermogravimetry and Raman spectroscopy, the thin MWCNTs show the purity of 70% and the degree of crystallinity (IG/ID) of 6.92, respectively.Field emission measurement was demonstrated for the three samples which were varied by Mo concentration of 0.025, 0.05, and 0.075 in the catalysts. The emission area was 0.19625 cm2 at the vacuum level of 5 x 10-7 Torr. The turn-on field, which is correspondent to the current density of 0.1 mA/cm2, is about 1.04 V/μm, 1.09 V/μm, and 1.55 V/μm for each t-MWCNTs samples, respectively. The threshold fields of each samples are 1.99 V/μm, 2.04 V/μm, and 2.8 V/μm at the current density of 1.0 mA/cm2, respectively. The measured lifetime revealed good emission stabilities for 20 hours during a constant DC applied bias. Field emission performance was clearly dependent on the diameter of thin MWCNTs. It is suggested that diameters and the graphene layers of t-MWCNTs can be simply controlled by changing Mo content within Fe-Mo/MgO bimetallic catalysts and the produced high-quality t-MWCNTs can be used to efficient field emitters.
9:00 PM - P4.5
Clay-Assisted Dispersion of Single-Walled Carbon Nanotubes in Epoxy Nanocomposites.
Jaime Grunlan 1 2 3 , Lei Liu 3
1 Mechanical Engineering, Texas A&M University, College Station, Texas, United States, 2 Chemical Engineering, Texas A&M University, College Station, Texas, United States, 3 Materials Science and Engineering, Texas A&M University, College Station, Texas, United States
Show Abstract9:00 PM - P4.6
Immobilization of CNT on Bamboo Charcoal by TEOS Vapor.
Jiangtao Zhu 1 , Fung Luen Kwong 1 , Dickon H. L. Ng 1
1 Department of Physics, The Chinese University of Hong Kong, Hong Kong China
Show AbstractA composite of carbon nanotube (CNT) and activated carbon (C) is an excellent catalyst or catalyst support. It can be used in the selective chemisorption of unwanted species from drinking water. The CNT enhances the specific surface area and the adsorption ability of the composite. A major challenge is to grow or to anchor the CNT on designate positions of the carbon support. Bio-organic material like bamboo provides plentiful surface morphology to achieve this task. In this study, we have successfully anchored or immobilized CNTs on a bamboo charcoal by using chemical vapor deposition of gaseous tetraethyl orthosilicate (TEOS). Electron microscopies and Raman spectrometer are used to characterize the C-CNT composite. Pure graphite sheet and silicon wafer are used as substrate in the control experiments, obtained results are compared with those from bamboo charcoal. The immobilization of the CNTs on bamboo charcoal is analyzed and the growth mechanism of CNT is studied. It is found that CNTs with length of several micrometers and diameter from 50nm to 300nm are spreading on the bamboo charcoal matrix. They have formed different patterns according to different structures of the original bamboo charcoal. For instance, some of the CNTs are aligned perpendicular to the surface of pore structure of bamboo charcoal, and some of them are randomly dispersed. From the high resolution transmission analysis, we find that the CNTs are composed of ~30 layers of amorphous and graphitic carbon. Amorphous droplets containing silicon and calcium are also found at the tips of the CNTs, and this suggested that the growth of the CNT is via a vapor-liquid-solid mechanism. The calcium impurity is originated from the bamboo charcoal, and Si is supplied by the TEOS. Both have played a critical role on the growth of CNTs.
9:00 PM - P4.7
Spectroscopic Diagnostics of Atmospheric Pressure Water Plasma Treatment of Multiwalled Carbon Nanotubes.
Szetsen Lee 1 , Jr-Wei Peng 1 , Chi-Hung Liu 2
1 Chemistry, Center for Nano-technology, R&D Center for Membrane Technology, Chung Yuan Christian University, Chungli Taiwan, 2 Mechanical and Systems Research Laboratories, Industrial Technology Research Institute, Chutung Taiwan
Show AbstractMultiwalled carbon nanotubes (MWCNTs) have been treated with an atmospheric pressure plasma source using argon/water mixture. Optical emission spectroscopy (OES) has shown that hydroxyl radical (OH) was the major reactive species in plasma. Excitation and rotational temperatures of plasma were determined from Ar and OH emission lines. The structural change in MWCNTs was monitored by micro-Raman at D, G, and higher-order bands. The rates of change of intensity ratio, FWHM, and dispersion with respect to the plasma treatment time were correlated. It is found that dispersion appears to be insensitive to the plasma treatment time. On the other hand, the intensity ratio and FWHM are good Raman parameters for inspecting the topological and structural disorder in plasma-modified MWCNTs.
9:00 PM - P4.8
New Carbon Allotropes Produced by Hydrogen Plasma Exposure of Carbon Nanotubes.
Michael Behr 1 , Tejinder Singh 2 , Andre Muniz 2 , Dimitrios Maroudas 2 , Eray Aydil 1
1 Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota, United States, 2 Chemical Engineering, University of Massachusetts, Amherst, Massachusetts, United States
Show Abstract9:00 PM - P4.9
Development of Carbon Nanotubes Wiring for a Via Hole and an Apparatus for a 12-inch wafer.
Haruhisa Nakano 1 , Hirohiko Murakami 1
1 Tsukuba Institute for Super materials, ULVAC, Inc., Tsukuba, Ibaraki Japan
Show Abstract
Symposium Organizers
Li-Chyong Chen National Taiwan University
John Robertson Cambridge University
Zhong Lin Wang Georgia Institute of Technology
David B. Geohegan Oak Ridge National Laboratory
P8: Poster Session: Structural and Mechanical Properties
Session Chairs
Wednesday PM, March 26, 2008
Exhibit Hall (Moscone West)
1:00 AM - P8.1
High Resolution Electron Tomography and Atomic Resolution TEM of MoS2 Fullerenes.
Reshef Tenne 1 , Maya Bar Sadan 1 , Sharon Wolf 1 , Lothar Houben 2 , Andrey Enyashin 3 , Gotthard Seifert 3 , Knut Urban 2
1 Materials and Interfaces, Weizmann Institute of Science, Rehovot Israel, 2 Ernst Ruska Centre for Microscopy and Spectroscopy with Electrons, Research Centre Jülich, Jülich Germany, 3 Institute of Physical Chemistry and Electrochemistry, Technische Universität Dresden, Dresden Germany
Show AbstractMoS2 nanooctahedra are believed to be the smallest stable closed cage structures of MoS2, i.e. the genuine inorganic fullerenes. Their structure model was constructed by density functional tight binding calculations (DFTB) proceeded by molecular dynamics annealing. Sub-Ångström resolution aberration-corrected transmission electron microscopy (TEM) allowed validating the suggested atomic structure and the predicted nanooctahedra stability range. The high resolution TEM images, taken at negative spherical aberration imaging conditions (NCSI), successfully reveal the details of the atomic structure. The correspondence between the experimental images and suggested models is striking. It advances the atomic-scale understanding of the structures in an iterative way between theoretical calculations and experimental observation.In contrast to bulk and inorganic fullerene-like or nanotubular MoS2, which are semiconductors, the Fermi level of the nanooctahedra is situated within Mo d-bands making the particles metallic-like. According to the DFTB calculations the occurrence of metallic-like d-band conductivity is strongly related with defect formation at the apices and the seaming of the triangular faces at their edges. Moreover, for the first time, bright-field (BF) electron tomography was used to extract the 3D information of the closed cage structures in these high magnifications. Tomographic reconstruction of multiple TEM images is commonly used in biological sciences to study organic structures and morphologies in three dimensions. Only recently it has been applied to inorganic materials, focusing mainly on dark-field techniques in scanning transmission electron microscopy. We present the first promising tomographic reconstructions of IF nanoparticles.
1:00 AM - P8.10
Anisotropic Dielectric Polarization of individual Carbon Nanotubes studied by Electric Force Microscopy.
Wei Lu 1 , Yao Xiong 1 , Liwei Chen 1
1 , Ohio University, Athens, Ohio, United States
Show Abstract1:00 AM - P8.11
Dispersibility and Interfacial Interaction of Functionalized-Multiwalled Carbon Nanotubes in Nylon-6 Nano-composites.
Ronghua Zhang 1 , Robert Li 1
1 , City University of Hong Kong, Hong Kong China
Show AbstractConsidering that hyperbranched polymers show low melt-viscosity and multifunctional groups, which should provide good processability and functionality for the resultant composites. In the present work, multiwalled carbon nanotubes (MWNTs) were first functionalized by hyperbranched poly(urea-urethane)s (HPUs) through a polycondensation technique, forming multi-hydroxyl groups on the MWNTs surface. Nylon-6 (PA6)/functionalized-MWNTs with different MWNTs loadings were then prepared by a simple melt-compounding approach. MWNTs are dispersed uniformly in PA6 matrix and form cross-linking networks together with PA6 matrix, due to the chemical modification of MWNTs and polymer chains entanglement between PA6 and the grafted-HPUs on the surface of MWNTs. Dynamic mechanical properties and thermal stability of PA6 are effectively improve by the addition of functionalized-MWNTs when compared with the starting PA6 and PA6/un-functionalized-MWNT composites. One involves the enhanced dispersion of functionalized-MWNTs in polymer matrix, resulting in an effective transfer of load from polymer to MWNTs. Another involves the hydrogen-bonding interaction (OH...O=C) between hydroxyl groups (OH) on the surface of MWNTs and carbonyl groups (C=O) within PA6 chains, which will increase the interfacial adhesion of matrix and MWNTs. In addition, the effect of functionalized-MWNTs on the crystallization behavior of PA6 will be also discussed.
1:00 AM - P8.12
Size-Dependence Peculiarities of Supported Small Clusters and their Effect on Single-Walled Carbon Nanotubes Growth.
Oleg Kuznetsov 1 , Elena Pigos 1 , Gugang Chen 1 , Toshio Tokune 2 , Avetik Harutyunyan 1
1 , Honda Research Institute USA Inc., Columbus, Ohio, United States, 2 , Honda R&D Co. Ltd., Saitama Japan
Show Abstract1:00 AM - P8.15
Stone-Wales Transformation:Precursor of Fracture in Carbon Nanotubes.
Jizhou Song 1 , Hanqing Jiang 2 , Yonggang Huang 3 , Minfeng Yu 1 , Kezhi Huang 4
1 , University of Illinois at Urbana-Champaign, Urbana, Illinois, United States, 2 , Arizona State University, Tempe, Arizona, United States, 3 , Northwestern University, Evanston, Illinois, United States, 4 , Tsinghua University, Beijing China
Show Abstract1:00 AM - P8.17
Synthesis and Structural Characterization of Carbon Nanostructured Materials with Catalyst Composition.
Hyunmin Cha 1 , Ji-hun Kang 1 , Jeong-Pyo Kim 1 , Sung-Il Jung 1 , Yeon-Gil Jung 1
1 School of Nano and Advanced Materials Engineering, Changwon National University, Changwon Korea (the Republic of)
Show AbstractThe aim of the present work is to report the microstructural evolution of carbon nanostructured materials, depending on catalyst composition and synthesizing condition. The effects of catalyst species and mole ratio in mixture compositions on the microstructural evolution of the carbon nanostructured materials, carbon nanotubes (CNTs) or carbon nanofibers (CNFs), have been investigated. Carbon nanostructured materials have been synthesized at 600 oC by thermal decomposition of ethylene (C2H4) as a carbon source over various compositions of Ni-Fe, Ni–Al, Fe-Al, and Ni–Fe–Al catalysts. The quantitative and qualitative properties are analyzed by various equipments of TG-DTA for thermal analysis, FT-IR for structural analysis, XRD for phase analysis, SEM and TEM for microstructural evaluation including EDS for elemental analysis, and BET for specific surface area, etc. The carbon nanostructure materials synthesized are CNT type, showing a fairly high length-to-diameter ratio with lengths of several to tens of micron meters and exhibiting many nodes along their axes. The morphology of CNTs depending on the composition and the mole ratio can be ascertained, according to the angles between the graphene layers and the growth axis. The Ni-Al catalyst is optimized composition to synthesize the CNTs, whereas the Ni-Fe catalyst is not helpful in synthesizing the CNTs. The presence of the Al component in the Ni and Fe catalysts promotes the growth and formation of the CNTs, showing the entangled and coiled microstructure with diameters in the range of 50–200nm. The thickness of the CNTs synthesized with the Ni-Al catalyst is dependent on the mole ratio of the Al component, showing the thickness increased with decreasing the Al mole ratio. The best mole ratio in the Ni-Al catalyst is 1:4 or 1:1 in this study, showing the thicknesses of approximately 100 nm.
1:00 AM - P8.18
Understanding Nano-Carbon Interactions Using Aromatic Amino-Acids.
Brian Cousins 2 1 , Yan ning Li 2 , Michael Roberts 2 , Linda Gross 2 , Rein Ulijn 2 1 , Ian Kinloch 2
2 Materials Science Centre, University of Manchester, Manchester United Kingdom, 1 Manchester Interdisciplinary Biocentre (MIB), University of Manchester, Manchester United Kingdom
Show AbstractCarbon nanotubes (CNTs) have shown potential in a range of fields from microelectronics and drug delivery to biosensors. The processing and solubilisation of single-wall (SWNT) and multi-wall (MWNT) nanotubes remains a significant barrier in their exploitation. Covalent surface modification has been achieved using strong acids, however, such methods damage and shorten the CNTs and hence the need for milder, non-covalent treatments(1). Herein, we study the interactions of Fmoc amino-acids and peptides with various nano-carbons, including CNTs. Four carbon surfaces of different curvatures (C60, SWNT, MWNT and graphite with diameters of 0.6 nm, 1 nm, 10-100 and ∞ (i.e. flat) were characterised by TEM, SEM and Raman spectroscopy. These materials were introduced to two peptide sequences known from phage display to have a strong affinity with CNTs (2). The first peptide used aromatic groups distributed evenly along the chain (HWKHPWGAWDTL), whilst the second peptide (HWSAWWIRSNQS) had an aromatic head group. Aqueous solutions of both peptides were mixed with carbon materials with the aid of ultrasonic energy. The stability of dispersions was analysed using UV spectroscopy and Beer’s law to give the concentration of material as a function of time. Carbon materials were studied with Fmoc protected aromatic amino-acids. The rate of absorption from solution on to clean carbon surfaces and the final equilibrium coverage was evaluated. It was found that aromatic amino-acids could successfully disperse CNTs (Fig 1). The aromaticity of Fmoc was found to be important when substituted with non-aromatic protected groups coupled with acetyl (Ac) or benzyloxycarbonyl (Z). Fig 1. The effect of Fmoc protected amino-acids on the dispersity of CNTs in phosphate buffered saline (PBS).The inclusion of Fmoc protected amino acids enabled the use of low cost, short sequences to disperse CNTs. Furthermore, Fmoc enabled additional functionality to be introduced, including molecular switching through changes in pH and the incorporation of CNTs in to self assembled hydrogel networks.
1:00 AM - P8.19
Pressure Dependent Conductivity of Strained Carbon Nanotube Networks on Elastomer Substrates.
Seung-Beck Lee 1 2 , Dong-Hun Min 1 2 , Chaehyun Lim 2 , Bonghyun Park 2 , Chang-Seung Woo 2
1 Electronics and Computer Engineering, Hanyang University, Seoul Korea (the Republic of), 2 Nanosemiconductor Technology, Hanyang University, Seoul Korea (the Republic of)
Show Abstract1:00 AM - P8.2
Microscopic and Raman Characterization of Graphene Produced by the High-Pressure High-Temperature Growth Method.
Farough Parvizi 1 , Suchismita Ghosh 1 , Irene Calizo 1 , Alexander Balandin 1 , Henry Zhu 2 , Reza Abbaschian 3
1 Nano-Device Laboratory, Department of Electrical Engineering and Materials Science and Engineering Program, University of California – Riverside, Riverside, California, United States, 2 , The Gemesis Corporation, Sarasota, Florida, United States, 3 Department of Mechanical Engineering and Materials Science and Engineering Program, University of California – Riverside, Riverside, California, United States
Show AbstractGraphene has recently attracted major attention from the research community. In addition to its unusual physical properties it also shows promise as a material for electronic and detector applications. In order to achieve further progress in graphene electronics one has to develop a technology for producing a large area continuous graphene sheets with a controlled number of layers and low defect density. Here we report on the properties of graphene produced by the high-pressure high-temperature (HPHT) growth process from the low-grade natural graphite. The HPHT growth in the split sphere apparatus was previously used for the diamond growth. The resulting graphene flakes were transferred to silicon substrates for the micro-Raman, optical and scanning electron microscopy inspection. The micro-Raman spectroscopy can be used to characterize graphene on different substrates [1-2]. The analysis of the G peak, D and 2D bands in Raman spectra under the 488-nm excitation indicate that the HPHT technique is capable of producing the high-quality large-area single-layer graphene layers with a low defect density. The proposed method may lead to a more reliable graphene synthesis and facilitate its chemical doping. AAB acknowledges support from the Focus Center Research Program (FCRP) - Center on Functional Engineered Nano Architectonics (FENA).[1] I. Calizo, A.A. Balandin, W. Bao, F. Miao and C.N. Lau, Nano Letters, 91, 071913 (2007); I. Calizo, F. Miao, W. Bao, C.N. Lau and A.A. Balandin, Appl. Phys. Lett., 91, 071913 (2007).[2] I. Calizo, W. Bao, F. Miao, C.N. Lau and A.A. Balandin, “The effect of substrates on the Raman spectrum of graphene: Graphene-on-sapphire and graphene-on-glass,” Appl. Phys. Lett., to appear, 2007.
1:00 AM - P8.20
Mechanical Properties of Mats of Well-aligned Multi-Walled Carbon Nanotubes.
Christian Deck 1 , Brandon Reynante 1 , Gregg McKee 1 , Kenneth Vecchio 1
1 Mats. Sci., UC San Diego, La Jolla, California, United States
Show AbstractCarbon nanotubes (CNTs) have been the subject of great interest in many fields, due to their exceptional mechanical properties and geometry. In particular, they possess exceptional mechanical strength, which is desirable in many diverse applications, such as sensing devices and composite reinforcement. In this work, the mechanical properties of mats of well-aligned multi-walled CNTs were investigated. A stage was designed and built to allow in-situ scanning electron microscopy observation of compression, tension, and shear testing of densely-packed mats of well-aligned multi-walled CNTs. Force measurements were taken and the elastic modulus of the CNT mats was measured under different testing configurations; modulus values ranged from <1GPa in compression to roughly 35GPa in tension. In addition, other properties such as tube-substrate bond strength and time-dependent responses were investigated.
1:00 AM - P8.21
Optical and Electrical Properties of Carbon Nanotube/Conjugated Polymer Composites.
Xiaoguang Mei 1 , Kuan Sun 1 , Benhu Fan 1 , Jianyong Ouyang 1
1 Materials Science & Engineering, National University of Singapore, Singapore Singapore
Show Abstract1:00 AM - P8.22
Probing the Boron Fullerene Family with Computer Simulations.
Arta Sadrzadeh 1 , Olga Pupysheva 1 , Abhishek Singh 1 , Boris Yakobson 1
1 ME&MS Department, Rice University, Houston, Texas, United States
Show Abstract1:00 AM - P8.23
A Model of Dry-drawing of Multiwall Carbon Nanotube Forests into Self-assembled Sheets.
Alexander Kuznetsov 1 , Alexandre Fonseca 1 , Kyeongjae Cho 2 , Ray Baughman 1 , Anvar Zakhidov 1
1 NanoTech Institute, University of Texas at Dallas, Dallas, Texas, United States, 2 Physics Department, University of Texas at Dallas, Dallas, Texas, United States
Show AbstractRecently a new dry-state technique has been developed in UTD to produce highly-oriented, free-standing multiwall carbon nanotube (MWNT) sheets which are mechanically strong and oriented, and can be converted into transparent sheets and yarn-fibers by twist-spinning [1,2].In the present talk, a simple model is developed which allows describing the main features of dry-drawing self-assembly of vertically oriented multiwall carbon nanotube (MWCNT) forest into horizontal thin MWCNT sheets or yarns, developed in [1].The model is based on two main concepts: 1. Self-strengthening of interbundle nanotube connections during the bending-by-draw and rotation of the bundles (basic elements of the forest). 2. Rearrangement of bundles by accordion-type stretching motion accompanied by detachment of bundles (at the top and bottom of the forest). This detachment occurs due to strengthening of interconnections in a given region of the bundle. It gives rise to a critical force, which pulls the next bundle from the forest, keeping the process of dry-drawing continuous.Model explains the range of forest heights: Lmin < L < Lmax, and interconnection densities, for which the dry-self assembly is possible, and allows predicting the structure and density of the sheet. The tuning of the interbundle connections by varying catalyst deposition conditions [3] for CVD grown forest allowed obtaining MWCNT sheets of variable geometry and strength.1. M. Zhang, S. Fang, A.A. Zakhidov, S.B. Lee, A.E. Aliev, C.D. Williams, K.R. Atkinson, R.H. Baughman, Science 2005, 309, 12152. M. Zhang, K. R. Atkinson, R.H. Baughman, Science 2004, 306, 13583. R. Ovalle Robles, X. Lepro Chavez, A. Kuznetsov, R.H. Baughman, A.A. Zakhidov (MRS Spring Meeting 2008 Proc. 2008)
1:00 AM - P8.24
Entanglement and the Nonlinear Elastic Behavior of Forests of Coiled Carbon Nanotubes.
Vitor Coluci 1 , Alexandre Fonseca 2 , Douglas Galvao 1 , Chiara Daraio 3
1 Applied Physics Department, State University of Campinas, Campinas, Sao Paulo, Brazil, 2 The MacDiarmid NanoTech Institute, University of Texas at Dallas, Richardson, Texas, United States, 3 Aeronautics and Applied Physics, California Institute of Technology, Pasadena, California, United States
Show AbstractThe study of nanostructures, in special carbon nanotube(CNTs) and nanowires have been object of intense experimental and theoretical investigations due to their large range of possible applications and new physical phenomena. Among these nanostructures helical and coiled structures have a special place due to their differentiated mechanical behavior [1]. Coiled carbon nanotubes (CCNTs) were first predicted to exist in the early 1990s[2] and experimentally observed in 1994[3].Recently, the dynamical response of a foamlike forest of CCNTs under impact of a drop-ball has been reported[4]. The experiment consisted of producing arrays of bundles of CCNTs, let a stainless steel bead falls down on the forest of CCNTs, and measure the dynamic force at the wall below the forest during the stages of penetration and restitution. The analysis of the forest's morphology after impact has shown no trace of plastic deformation and a full recovery of the foamlike layer of CCNTs under various impact velocities. The contact force exhibits a strongly nonlinear dependence on displacement and appears fundamentally different from the response of a forest of CNTs.We have derived an analytical model for the nonlinear behavior of the impact response of a forest of CCNTs including geometrical and physical aspects during the forest compression. We showed that the nonlinear behavior is fully described when the entanglement of the coiled carbon nanotubes in the superior part of the forest surface is incorporated into the model. This entanglement among neighbors is due to the bending of the coil tips produced by the ball impact. The model results point out to the importance of the coil entanglements for the elastic behavior of such systems. The present model is able to provide, by matching experimental values, estimates of the spring constant of a single CCNT and the level of entanglement between CCNTs. These aspects can play an essential role in the future design of microelectro-mechanical systems devices, new shock protecting layers, and composites for microelectronic packaging and vibration mitigating materials where CCNT structural entanglement could be present.[1] A. F. da Fonseca and D. S. Galvao, Phys. Rev. Lett. 92, 175502 (2004).[2] B. I. Dunlap, Phys. Rev. B 46, 1933 (1992).[3] X. B. Zhang, X. F. Zhang, D. Bernaerts, G. T. Vantendeloo, S. Amelinckx, J. Vanlanduyt, V. Ivanov, J. B. Nagy, P. Lambin,A. A. Lucas, Europhys. Lett. 27, 141(1994).[4] C. Daraio, V. F. Nesterenko, S. Jin, J. Appl. Phys. 100, 064309 (2006)
1:00 AM - P8.3
Diameter and Chirality Dependent Redox Chemistry of Chromatographically Enriched Identical (n, m) Carbon Nanotubes.
Wei Zhao 1
1 Chemistry, University of Arkansas, Little Rock, Arkansas, United States
Show Abstract1:00 AM - P8.4
Alignment of Multi-Walled Carbon Nanotube inside Confined Channel of PS/LDPE Formed by Continuous Shear Force.
Younghwan Kwon 1 , Chao Cao 1
1 Department of Chemical Engineering, Daegu University, Gyeongsan Korea (the Republic of)
Show AbstractRheological behavior of polystyrene/multi-walled carbon nanotubes (PS/MWCNT) nanocomposites containing MWCNT concentrations between 0.1wt% and 10wt% was investigated using oscillatory rheometer. For this study, the optimum conditions for dispersion of MWCNTs were systematically studied with varying processing variables such as the content of surfactants, the sonication time, solvents, the content of MWCNTs, different molecular weights of PS. It was found from the results that increase in viscosity of the nanocomposites was accompanied by increase in the elastic melt properties, represented by the storage modulus G’ and the loss modulus G’’. The elastic share of the nanocomposites was also increased with the increasing contents of MWCNTs. Significant changes in the frequency-dependent moduli and complex viscosity were observed between 2 wt% and 5 wt% of MWCNTs, indicating a rheological transition from a viscous to an elastic behaviour of the composites with increasing MWCNT composition. The phase transition of the gel point of MWCNT/PS composites was measured to be 3.2 wt% of MWCNTs. For alignment of MWCNT in polymer matrix, an immiscible polymer blend (PS/LDPE) was used as a template. MWCNT composites in PS/LDPE were continuously treated under a constant shear force at 200 oC and fixed shear rate of 10 S-1, and MWCNT/PS nanocomposites were directionally elongated. The samples were fractured at liquid nitrogen atmosphere to make a smooth surface by parallel and perpendicular direction of shear force. Additionally, PS was extracted with toluene for several hours. SEM results revealed morphology of MWCNT in the PS/LDPE matrix, indicating alignment of MWCNT parallel to flow direction of polymer matrix.
1:00 AM - P8.5
Influences of Hydrogen Gas on Carbon Nanotube Growth.
Fumitaka Ohashi 1 , Guan Chen 2 , Vlad Stolojan 1 , Ravi Silva 1
1 Advanced Technology Institute, University of Surrey, Guildford, Surrey, United Kingdom, 2 , Surrey Nanosystems, Newhaven United Kingdom
Show Abstract1:00 AM - P8.6
WITHDRAWN 02/21/08 Variation of the Gruneisen Constant with Frequency and Radius in Carbon Nanotubes.
Steven Hepplestone 1 , Gyaneshwar Srivastava 1
1 School of Physics, University of Exeter, Exeter, Devon, United Kingdom
Show AbstractWednesday, March 26WithdrawnPosterP8.6
1:00 AM - P8.7
Surface and Wetting Properties of Vertically Aligned CNT Arrays.
C. Wirth 1 , Stephan Hofmann 1 , John Robertson 1
1 Engineering, Cambridge University, Cambridge United Kingdom
Show Abstract1:00 AM - P8.9
Liquid and Solid Dispersions of Single-Walled Carbon Nanotubes.
Hui Xu 1 , Hiroya Abe 1 , Makio Naito 1 , Hideki Ichikawa 2 , Yoshinobu Fukumori 2 , Shigehisa Endoh 3 , Kneji Hata 3
1 , Osaka University, Ibaraki Japan, 2 , Kobe Gakuin University, Kobe Japan, 3 , Advanced industrial acience and technology, Tukuba Japan
Show AbstractP6: Graphene
Session Chairs
David Geohegan
Philip Kim
John Robertson
Wednesday PM, March 26, 2008
Room 3003 (Moscone West)
9:30 AM - **P6.1
Graphene-based Materials.
Rodney Ruoff 1
1 Mechanical Engineering, University of Texas at Austin, Austin, Texas, United States
Show Abstract10:00 AM - P6.2
Temperature and Interface Effects on Raman Spectrum of Graphene Layers on Silicon, Sapphire, Gallium Arsenide and Glass Substrates.
Irene Calizo 1 , F. Miao 2 , W. Bao 2 , C. Lau 2 , A. Balandin 1
1 Electrical Engineering, University of California - Riverside, Riverside, California, United States, 2 Physics and Astronomy, University of California - Riverside, Riverside, California, United States
Show AbstractSince its recent isolation and measurements, graphene has attracted extraordinary attention from the materials research community. In addition to the wealth of the 2D-electron gas physics it reveals, graphene is a promising material for electronic applications beyond conventional CMOS technology. Raman spectroscopy has proven to be the most reliable way for counting the number of atomic graphene layers and verifying its quality. We investigated the effect of temperature on Raman spectra of graphene on Si/SiO2 substrates. The extracted value of the temperature coefficient of G mode of graphene is =-0.016 cm-1/°C for the single-layer and =-0.015 cm-1/°C for the bi-layer [1]. We studied Raman signatures from graphene layers on GaAs, sapphire and glass substrates and compared them with those from graphene on the standard Si/SiO2 substrate [2]. It was found that while G peak of graphene on Si/SiO2 and GaAs is positioned at 1580 cm-1 it is down-shifted by ~5 cm-1 for graphene-on-sapphire and, in some cases, splits into doublets for graphene-on-glass. The obtained results are important for nanometrology of graphene. AAB acknowledges support from the Focus Center Research Program (FCRP) - Center on Functional Engineered Nano Architectonics (FENA).[1] I. Calizo, A.A. Balandin, W. Bao, F. Miao and C.N. Lau, Nano Letters, 91, 071913 (2007); I. Calizo, F. Miao, W. Bao, C.N. Lau and A.A. Balandin, Appl. Phys. Lett., 91, 071913 (2007).[2] I. Calizo, W. Bao, F. Miao, C.N. Lau and A.A. Balandin, “The effect of substrates on the Raman spectrum of graphene: Graphene-on-sapphire and graphene-on-glass,” Appl. Phys. Lett., to appear, 2007.
10:15 AM - **P6.3
Epitaxial Graphene for Nanoelectronics.
Walt de Heer 1
1 , Georgeia Instittue of Technology, Atlanta, Georgia, United States
Show Abstract10:45 AM - P6.4
Measurement of Ultrafast Carrier Dynamics in Epitaxial Graphene.
Jahan Dawlaty 1 , Shriram Shivaraman 1 , Mvs Chandrashekhar 1 , Michael Spencer 1 , Farhan Rana 1
1 Electrical and Computer Engineering, Cornell University, Ithaca, New York, United States
Show AbstractUnusual electronic properties of graphene has attracted a large number of fundamental studies [1] and has inspired a variety of device proposals such as THz emitters [2], high speed transistors [3], and universal material for fabrication of nanometer-sized circuitry [4] and sensors [5].Understanding of carrier dynamics is essential to a variety of proposed graphene based devices. While there is an abundance of literature on ultrafast optical response of other low dimensional carbons [6-7], ultrafast carrier dynamics in graphene have so far not been studied. Most of the work on graphene has been conducted on micromechanically cleaved samples from graphite. Although this method results into high quality films, it is not reliable for large scale production. Epitaxial growth of graphene by thermal decomposition of SiC has been investigated extensively as a promising alternative [8]. In this paper, we report measurement of carrier relaxation times in epitaxially grown graphene using optical pump-probe techniques. The samples were grown on the C face of 6H semi-insulating SiC wafers at temperatures ranging from 1300 C to 1600 C. The growth of carbon on the substrate was verified by Raman spectroscopy. A Ti:sapphire mode-locked laser was used for time-resolved pump-probe spectroscopy of the samples. Pump pulses with energies between 5-15 nJ were used to generate photo-excited carriers, while weak probe pulses (~0.1 nJ) were used to probe the transient changes in the transmittivity of the samples.We find that the transmittivity of the samples increases sharply upon photoexcitation. The recovery of the transmittivity exhibits two distinct time scales – an initial steep decay (~100 fs) followed by a longer relaxation time (0.5-1.7 ps). The initial increase in transmittivity is consistent with band-filling (absorption saturation) by the photo-excited carriers. The fast component of the transmittivity decay is attributed to thermalization of the photo-excited carriers through carrier-carrier and optical phonon scattering. The slow component is attributed to the subsequent cooling of the hot carrier distribution through phonon scattering and also to electron-hole recombination. The observed time-scales are comparable to those of other low dimensional carbons such single-walled carbon nanotubes [7].[1] A. K. Geim and K. S. Novoselov, Nature Materials, (6) 183[2] F. Rana and F. Ahmad arXiv:0704.0607v2 [cond-mat.mes-hall][3] K. S. Novoselov et. al. Science, (306) 666 [4] Zhihong Chen, arXiv:cond-mat/0701599v1 [cond-mat.mtrl-sci][5] F. Schedin et. al. Nature Materials, (6) 652 [6] J. S. Lauret, Physical Review Letters, (90) 5, 057404-1[7] Ying-Zhong Ma et. al. Journal of Chemical Physics, (120),7, 3368[8] W. A. de Heer et. al. arXiv:0704.0285v1 [cond-mat.mes-hall]
11:30 AM - **P6.5
Electric Transport in Carbon Nanotubes and Graphene.
Philip Kim 1
1 Physics, Columbia University, New York, New York, United States
Show AbstractThe massless Dirac particle moving at the speed of light has been a fascinating subject in relativistic quantum physics. Graphene, an isolated single atomic layer of graphite, now provides us an opportunity to investigate such exotic effect in low-energy condensed matter systems. The unique electronic band structure of graphene lattice provides a linear dispersion relation where the Fermi velocity replaces the role of the speed of light in usual Dirac Fermion spectrum. In this presentation I will discuss experimental consequence of charged Dirac Fermion spectrum in two representative low dimensional graphitic carbon systems: 1-dimensional carbon nanotubes and 2-dimensional graphene. Combined with semiconductor device fabrication techniques and the development of new methods of nanoscaled material synthesis/manipulation enables us to investigate mesoscopic transport phenomena in these materials. The exotic quantum transport behavior discovered in these materials, such as room temperature ballistic transport and unusual half-integer quantum Hall effect. In addition, the promise of these materials for novel electronic device applications will be discussed.
12:00 PM - P6.6
Electronic Charge and Spin Transport in Epitaxial Few-layer Graphene Films.
Peide (Peter) Ye 1 , Tian Shen 1 , Yang Sui 1 , Yanqing Wu 1 , Michael Capano 1 , James Cooper 1
1 , Purdue University, West Lafayette, Indiana, United States
Show Abstract12:15 PM - P6.7
Scanning Kelvin Probe Force Microscopy on Charged Single- and Bilayer Graphene.
Dominik Ziegler 1 , Christoph Stampfer 2 , Francoise Molitor 2 , Davy Graf 2 , Andreas Stemmer 1
1 Department of Mechanics and Process Engineering, Nanotechnology Group, ETH Zurich, Zurich Switzerland, 2 Department of Physics, Nanophysics Group, ETH Zurich, Zurich Switzerland
Show Abstract12:30 PM - P6.8
Graphene as a Low-noise Electronic Material: Suppressed Low-frequency Current Fluctuations in Bilayer Graphene Nano-ribbons.
Yu-Ming Lin 1 , Phaedon Avouris 1
1 T. J. Watson Research Center, IBM, Yorktown Heights, New York, United States
Show Abstract12:45 PM - P6.9
Synthesis and Electronic Properties SWCNT Sheets
David Lashmore 1 , Mark Schauer 1 , Brian White 1 , David Degtiarov 1 , Jennifer Mann 1
1 , Nanocomp, Concord, New Hampshire, United States
Show AbstractP9: Applications: Overview
Session Chairs
Wednesday PM, March 26, 2008
Room 3003 (Moscone West)
2:30 PM - **P9.1
Carbon Nanotube Applications: A Progress Report.
Meyya Meyyappan 1
1 , NASA Ames Research Center, Moffett Field, California, United States
Show AbstractThough carbon nanotubes (CNTs) exhibit acknowledged unique electronic properties and extraordinary mechanical properties and research on numerous applications has been in progress for about 5-7 years, commercialization has not yet happened on a large scale. Out group has been working on applications of CNTs in chemical and biosensors, x-ray tubes and interconnects for over five years. While early results on growth, characterization, and quick demonstration of application potential have been easier to publish, system development takes significant time and faces numerous challenges. This talk will provide a progress report on system development in the application fields mentioned above. The author gratefully acknowledges the dedicated long term work by Jing Li, Y. Lu, Jun Li, P. Arumugham, H. Chen, C.V. Nguyen, X. Sun, and Q. Ngo for their contributions to the CNT applications and Prof. Cary Yang for a fruitful collaboration.
3:00 PM - **P9.2
CNTs for Fuel Cell and Supercapacitor Applications.
Kuei-Hsien Chen 1 2 , Chen-Hao Wang 1 , He-Yun Du 2 , Hsin-Cheng Hsu 2 , Chia-Liang Sun 1 , Jerry Chojung Huang 1 , Wei-Chuan Fang 3 , Jin-Hua Huang 3
1 Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei Taiwan, 2 Center for Condensed Matter Sciences, National Taiwan University, Taipei Taiwan, 3 Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu Taiwan
Show AbstractThe feasibility of a high-performance membrane-electrode-assembly (MEA), with low electrocatalyst loading on carbon nanotubes (CNTs) grown directly on carbon cloth as an anode has been demonstrated in this paper. The direct growth of CNTs [1-2] was synthesized by microwave plasma-enhanced chemical vapor deposition using on carbon cloth (CC). The cyclic voltammetry and electrochemical impedance reveal a fast electron transport and a low resistance of charge transfer on the direct growth of CNT. The electrocatalysts, platinum and ruthenium, were coated on CNTs either by sputtering or by ethylene glycol (EG) reduction [3] technique to form Pt-Ru/CNTs-CC electrode. It’s concluded that nitrogen doping in the CNTs plays a crucial role to facilitate subsequent nucleation of electrocatalysts.[4] Pt-Ru electrocatalysts are uniformly dispersed on the CNT, as indicated by HRSEM and TEM. The MEA, the sandwiched structure which comprises 0.4 mg cm-2 Pt-Ru/CNTs-CC as the anode, 3.0 mg cm-2 Pt black as the cathode and Nafion-117 membrane at the center, performs very well in a direct methanol fuel cell (DMFC) test. [5] The micro-structural MEA analysis shows that the thin electrocatalyst layer is uniform, with good interfacial continuity between membrane and the gas diffusion layer.Likewise, we take advantage of the high surface area and direct electrical conduction path of the CNTs and deposite RuO2, instead of Pt-Ru, on the surface of the CNTs. Supercapacitor can thus be fabricated based on the CNT-RuO2 nanocomposite. [6] Not only the capacitance but also the charge-discharge rate has been significantly enhanced. This is particularly attractive for future high power capacitor applications.References:[1] L. C. Chen, C. Y. Wen, C. H. Liang, W. K. Hong, K. J. Chen, H. C. Cheng, C. S. Shen, C. T. Wu and K. H. Chen, Adv. Fun. Mate. 12, 687, (2002).[2] C. L. Sun, L. C. Chen, M. C. Su, L. S. Hong, O. Chyan, C. Y. Hsu, K. H. Chen, T. F. Chang and L. Chang, Chem. of Mater. 17, 3749 (2005).[3] C. Bock, C.Paquet, M. Couillard, G.A. Botton, and B.R. MacDougall, J. Am. Chem. Soc. 126, 8028 (2004).[4] C.L. Sun, H.W. Wang, M. Hayashi, L.C. Chen, K.H. Chen, J. Am. Chem. Soc. 128, 8368 (2006).[5] C.H. Wang, H.-Y. Du, Y.T. Tsai, C.P. Chen, C.J. Huang, L.C. Chen, K.H. Chen, and H.C. Shih, J. Power Sources 171, 55-62 (2007). [6] W.C. Fang, J.H. Huang, C.L. Sun, K.H. Chen, O. M. Chyan, C.T. Wu, C.P. Chen and L.C. Chen, Electrochimica Comm. 9, 239 (2007).
3:30 PM - P9:App1ChallOut
BREAK
Symposium Organizers
Li-Chyong Chen National Taiwan University
John Robertson Cambridge University
Zhong Lin Wang Georgia Institute of Technology
David B. Geohegan Oak Ridge National Laboratory
P14: Molecular and Chemical Sensors
Session Chairs
Thursday PM, March 27, 2008
Room 3003 (Moscone West)
4:30 PM - **P14.1
Molecular Sensors based on Carbon Nanostructures.
Eric Snow 1 , Erik Alldredge 1 , Stefan Badescu 1 , Navdeep Bajwa Bajwa 1 , Keith Perkins 1 , Tom Reinecke 1 , Jeremy Robinson 1 , Paul Sheehan 1 , Zhongqing Wei 1
1 , Naval Research Laboratory, Washington, District of Columbia, United States
Show Abstract5:00 PM - P14.2
Selective Sensing of DMMP and NH3 Using CNTFET Array Based Gas Sensors Fabricated Using Metal Diversified Electrodes for Electronic Fingerprinting.
Paolo Bondavalli 1 , Pierre Legagneux 1 , Didier Pribat 2
1 NANOCARB, Thales research and technology, Palaiseau, Essonne, France, 2 LPICM, Ecole Polytechnique, Palaiseau, Essonne, France
Show AbstractThis paper deals with the prove of concept of a new concept to improve dramatically gas sensors based on Carbon Nanotube Field Effect transistors (CNTFETs) [1]. As we told in a former presentation [2], such devices exploit the extremely sensitive change of the Schottky barrier heights between Single Wall Carbon NanoTubes (SWCNTs) and drain/source metal electrodes: the gas adsorption creates an interfacial dipole that modifies the metal work function and so the bending and the height of the Schottky barrier at the contacts [3,4]. Actually, considering that no cheap and rapid method, up to now, exists for separating semiconductor from metallic specimens, we decided to use SWCNT mats as transistor channel. In fact, as far as random networks of SWCNT are concerned, it has been shown that, through a percolation effect, an overall semiconductor behaviour could be obtained, for carefully controlled areal densities [5]. Therefore using CNTFET array fabricated using SWCNT mat, we have achieved a sort of electronic fingerprinting of different gases using a CNTFET based sensors array. Specifically, this fingerprinting concept is based on the fact that the change of the metal electrode work function strictly depends on the metal/gas interaction and consequently the CNTFET transfer characteristics will change specifically as a function of this interaction. In a previous paper [6], we demonstrated that using Au, Pd, Pt metal we achieve a change of the transfer characteristics which is different for each transistors after exposure to 2ppm DMMP gas (DiMethyl-Methyl-Phosphonate, nerve agent-simulant) : we observed a current reduction of 90% for Pd, 80% for Au and 20% for Pt [6]. To father implement our demonstration, we have fabricated different CNTFETs using more metal contacts (Au, Pd, Mo, Pt, Ti, Ni) and exposed them to two gases, DMMP and NH3, which have the same “electron-donating” behavior. We have exposed our array to a sub ppm concentration of 0.5ppm of DMMP and NH3 and we have identified two electronic fingerprinting. In this way we have definitively demonstrated the high selectivity of our concept also for gas with similar electronic behavior (results will be shown during the conference). The totality of our measures have been performed at ambient conditions. We think that this new approach can be applied for highly selective sensing of a large number of gases using ultra-compact, room temperature and very low power devices. [1] P .Bondavalli, P.Legagneux, P .Lebarny (FR), D.Pribat (FR), J.Naigle(FR), WO2005048350[2] P.Bondavalli, P.Legagneux, D.Pribat, E.Chastaing, MRS Fall Meeting 2006, Boston [3] P.Avouris et al., Proceeding of the IEEE, Vol.91, n°11 (2003)[4] F.Leonard, J.Tersoff, Phys.Rev.Lett. 84, n°20 (2000)[5] S. Kumar,1 J.Y. Murthy, and M. A. Alam, , PRL 95, 066802 (2005)[6] P.Bondavalli, P.Legagneux, D.Pribat, Gas fingerprinting using Carbon Nanotubes transistors arrays, Proceedings of NANOTECH07 (Santa Clara, 20-24 Mai 2007)
5:15 PM - P14.3
Detection of Small Molecules and Metal Ions using Single-Walled Carbon Nanotubes.
Brett Allen 1 2 , Pingping Gou 1 , Padmakar Kichambare 1 , Alexander Star 1 2
1 , University of Pittsburgh, Pittsburgh, Pennsylvania, United States, 2 , National Energy Technology Lab, Pittsburgh, Pennsylvania, United States
Show AbstractBecause single-walled carbon nanotubes (SWNTs) are entirely comprised of surface atoms, they present an electronic structure that is extremely sensitive to perturbations in the local charge environment. As such, many research groups have examined the use of carbon nanotubes as sensors for both biologically relevant species1 as well as vapor and gas detection.2 To improve sensitivity and selectivity of the nanotube sensors, chemical functionalization of carbon nanotubes is typically employed. In particular, polymers were used to functionalize carbon nanotubes toward selective detection of NH3, NO2, and CO2 gases. Most recently we have implemented selective polymer-SWNT functionalization schemes for the detection of nitric oxide (NO), a biologically relevant marker for asthma,3 and various transition metal ions.4 In addition to the use of polymers to functionalize carbon nanotubes for selective gas detection, metal and semiconducting nanoparticles have been also used. For example, we have recently demonstrated5 selective detection of H2, CO, CH4, NH3, NO2, and H2S gases by a sensor array of metal-decorated carbon nanotube devices. 1) Allen, B. L.; Kichambare, P. D.; Star, A. “Carbon nanotube field-effect-transistor-based biosensors”, Adv. Mater. 2007, 19, 1439-1451.2) Snow, E. S.; Perkins, F. K.; Robinson, J. A. “Chemical vapor detection using single-walled carbon nanotubes”, Chem. Soc. Rev. 2006, 35, 790-798.3) Kuzmych, O.; Allen, B. L.; Star, A. “Carbon nanotube sensors for exhaled breath components”, Nanotechnology 2007, 18, 375502.4) Gou, P.; Kichambare, P. D.; Star, A. submitted.5) Star, A.; Joshi, V.; Skarupo, S.; Thomas, D.; Gabriel, J.–C. P. “Gas sensor array based on metal-decorated carbon nanotubes”, J. Phys. Chem. B 2006, 110, 21014-21020.
5:30 PM - P14.4
Carbon Nanotube/Polythiophene Hybrid Materials for High-performance Chemical Sensors.
Fei Wang 1 , Timothy Swager 2
1 Department of Materials Science and Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts, United States, 2 Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts, United States
Show Abstract5:45 PM - P14.5
Chemoselective Polymers, Nanoparticles, and Nanotubes in Chemical Sensor and Preconcentrator Applications.
Duane Simonson 1 , Robert McGill 1 , Michael Papantonakis 1 , Jennifer Stepnowski 1 2 , Bernadette Higgins 1
1 Code 6365, US Naval Research Laboratory, Washington, District of Columbia, United States, 2 1900 Elkin Street, NOVA Research, Inc., Alexandria, Virginia, United States
Show AbstractThe functionalization of polymers and nano-materials with 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) groups provides materials suitable for a variety of preconcentrator and sensor applications. These are especially useful in high vapor pressure, hydrogen-bond basic vapor collection. These specific interactions lead to high efficiency collection of basic analytes such as DMMP (organophosphonates), DNT, and TNT (nitroaromatics). Analytes such as RDX which have low vapor pressures have a larger dependence on surface interactions without specific (hydrogen bond) interactions. The use of carbosilane polymers with HFIP pendant groups offers dramatic improvements in sorbent capacity and thermal stability over fluoropolyol (FPOL) and siloxane polymers. In this work we will demonstrate the use of carbon nanotube (CNT) and carbon nanofiber (CNF) composites with carbosilane polymers as sorbent coatings and evaluate their use as solid-phase microextraction (SPME) coatings.
P16: Poster Session: CNTs Based Nanocomposite and Sensor
Session Chairs
Friday AM, March 28, 2008
Salon Level (Marriott)
9:00 PM - P16.1
Multilayer Fused Silica Based Carbon Nanotube and Carbon Fiber Microwave Absorbing Composite and its Mechanical Properties.
Yong Zhu 1 2 , Yubai Pan 1
1 , Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai China, 2 , Graduate School of the Chinese Academy of Sciences, Beijing China
Show Abstract9:00 PM - P16.10
Carbon Nanotube-based Liquid Crystal Micro Lenses.
Xiaozhi Wang 1 , Tim Wilkinson 1 , Ken Teo 1 , W. Milne 1
1 Electrical Division, Engineering Department, University of Cambridge, Cambridge United Kingdom
Show Abstract9:00 PM - P16.12
Self-Organisation of Highly Structured Carbon-Nanotube-Polymer Composites.
Izabela Jurewicz 1 , Eric Brunner 1 , Piyapong Asanithi 1 , Patnarin Worajittiphon 1 , Richard Sear 1 , Joseph Keddie 1 , Alan Dalton 1
1 Department of Physics, University of Surrey, Guildford United Kingdom
Show AbstractWe show the approach for tailoring the properties of nanocomposites by controlling the way in which nanomaterials are ordered using colloidally derived polymer latex crystals. We have focused on the development of a simple sedimentation process to obtain highly ordered multi-arrays of polymer particles which act as a template for the assembly of carbon nanotubes into three-dimensional hexagonal patterns, and create the possibility to overcome the problems with filler distribution. In the resulting composites, the individual particles deform into rhombic dodecahedra which is mainly driven by capillary forces as the system dries. Nanotubes are assembled and positioned at interstitial sites between the polymer particles resulting in a honeycomb-like arrangement. We will also show that the use of this facile and elegant technology allows the formation of robust mechanical composites with electrical percolations markedly lower than witnessed in more conventional polymer composites. The resulting composites maintain electrical properties but can undergo large strain before failure. More surprisingly, when the stress is released the sample returns to the original shape existing before the deformation while maintaining the inherent structural arrangement of nanotubes at interstitial points. The physical properties of these composites can be tuned by varying controllable parameters such as polymer glass transition, particle size and crystal assembly method.The advantage of the developed technique to arrange nanotubes in precise hexagonal patterns does not require expensive equipment and materials, and is not a time consuming procedure. The technology is a very promising candidate for a wide range of applications including conductive and transparent coatings, high performance composite materials and photonic crystals. Finally, by removing the latex polymer core we will attempt to produce hexagonal carbon nanotube membranes, which will potentially find application as photonic crystal materials used for, amongst other things to act as sensors or directors for light propagation.
9:00 PM - P16.13
The Role of Dispersion on Carbon Nanotube Reinforced Vinyl Ester/Glass Fiber Composites.
Laura Pena-Paras 1 , Hubert Phillips 1 , Dario Prieto-Centurion 1 , Enrique Barrera 1
1 MEMS, Rice University, Houston, Texas, United States
Show Abstract9:00 PM - P16.15
Single-walled Carbon Nanotube Thin Films for Biocatalytic Electrodes.
Dan Wang 1 , Jeffrey Rack 1 , Liwei Chen 1
1 Chemistry & Biochemistry, Ohio University, Athens, Ohio, United States
Show Abstract9:00 PM - P16.17
The Role of Interphases in Polymer Nanocomposites.
Ramanathan Thillaiyan 1 , Anny Flory 1 , Catherine Brinson 1
1 mechanical Engineering, Northwestern Universtiy, Evanston, Illinois, United States
Show Abstract9:00 PM - P16.18
Coaxial CNT-Polymer Wires by Electrospinning Method.
Timothy Longson 1 , Brett Cruden 2 , Claire Gu 1 , Ranadeep Bhowmick 3
1 Electrical Engineering, UCSC, Santa Cruz, California, United States, 2 Nano Research, NASA Ames, Moffett field, California, United States, 3 Materials Science and Engineering, Stanford, Stanford, California, United States
Show AbstractRealization of the exceptional properties of the carbon nanotube (CNT) at the macroscale still remain elusive to date. To make one dimensional macroscopic CNT structures for applications such as wiring or tethers requires fabrication of a CNT bundle that is well aligned, tightly packed together, and composed purely of CNTs. While some impressive progress toward this end has been demonstrated, there is still significant room for improvement. In this work, we discuss a step in this direction through development of a novel CNT bundle-core, polymer-shell coaxial fiber using a coaxial electrospinning technique. Electrospinning uses a high electric field to extract and align a viscoelastic solution into one-dimensional micro- and nano-structures. Short of being able to electrospin a solution of pure CNTs, which is not possible due to the lack of viscoelasticity required, this coaxial method results in the most dense CNT bundle achievable using electrospinning. As the polymer jet undergoes stretching and whipping induced by the bending instability, the CNTs in the core are aligned, compressed, and the solvent in which they are suspended is evaporated. This CNT bundle-core, polymer-shell coaxial electrospinning technique has been explored using a variety of polymers for the shell and a range of solvents for both the core and the shell. Out of the solutions tested it has been found that the conditions resulting in the highest yield is a shell of 10 wt. % PMMA/DMF with a flow rate of 4.0 ml/h, a core of 0.5 wt. % MWNT/DMF at a flow of 1.0 ml/h, drawn with an electric field of 33 KVDC/m. The resulting fibers have an average diameter of 2-5µm with a MWNT core of 0.8-1.5µm. These coaxial fibers are able to be arranged into well aligned, macroscopic bundles using a rotary collector with a linear velocity of 1.8 m/s. The morphology of the fibers has been verified using optical microscopy, Raman spectroscopy, Transmission Electron Microscopy, Scanning Electron Microscopy, and a Focused Ion Beam. These fibers are both electrically and mechanically promising. Potential applications include structural scaffolding, electrically conducting wires, chemical sensors, and strain-stress sensors. We will also discuss electrical characterization of the CNT core by selective removal of the polymer shell followed by direct measurement of the electrical conductivity of a single fiber, and preliminary mechanical characterization of the coaxial structure.
9:00 PM - P16.19
Dispersion of Single-walled Carbon Nanotubes Induced by Structural Effect of Perylene Derivatives and their Optoelectronic Properties.
Jin-Hyon Lee 1 , Seon-Mi Yoon 2 , Ki Kang Kim 3 , Jae-Young Choi 2 , Young Hee Lee 3 , Ungyu Paik 1
1 Division of Advanced Materials Science Engineering, Hanyang University, Seoul Korea (the Republic of), 2 Display Device & Material Lab. , Samsung Advanced Institute of Technology, Suwon Korea (the Republic of), 3 Department of Physics, Sungkyunkwan University, Suwon Korea (the Republic of)
Show Abstract9:00 PM - P16.21
Two-dimensional Gel Dielectrophoretic Separation of Metallic and Semiconducting Single-walled Carbon Nanotubes.
Charles Garson 1 3 4 , Xuliang Han 2 4 , Ryan Giedd 4 3 1
1 , Missouri State University, Springfield, Missouri, United States, 3 , Center for Applied Science and Engineering, Springfield, Missouri, United States, 4 , Roy Blunt Jordan Valley Innovation Center, Springfield, Missouri, United States, 2 , Brewer Science, Rolla, Missouri, United States
Show Abstract9:00 PM - P16.23
Transparent Boron-Doped Carbon Nanotube Films.
Xiaoming Liu 1 , Hugo Romero 1 , Humberto Gutierrez 1 , Peter Eklund 1 2
1 Department of Physics, Pennsylvania State University, University Park, Pennsylvania, United States, 2 Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania, United States
Show Abstract9:00 PM - P16.24
Size-dependent Solubility in Catalyst Nanoparticles and its Influence on the Growth of One-dimensional Nanostructures.
Na Li 1 , Teh Tan 1 , Neha Awasthi 1 , Wahyu Setyawan 1 , Stefano Curtarolo 1
1 Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, United States
Show AbstractCatalyst nanoparticles play a crucial role in the CVD growth of both carbon nanotubes and semiconductor nanowires. We propose a general formula, based on fundamental thermodynamic principles, to describe the solubility of the dissociated element (e.g. C) and the catalytically active phase of the particle (e.g. alpha/gamma Fe) as a function of the particle size. Ab initio computer simulations show that the solubility decreases dramatically with reducing particle size in the nanometer range when other phases compete for stability. The influence of the reduced solubility on the growth kinetics of 1-d nanostructures will be discussed under the given experimental conditions. In the case of extremely small particle sizes, we will discuss the results of both quantum mechanical and thermodynamic modeling.
9:00 PM - P16.25
Solution Phase Synthesis of Nanocomposites between Thiolated Multi-Walled Carbon Nanotubes and Gold Nanorod.
Mingdong Dong 1 , Zhangquan Peng 2 , Kim Daasbjerg 2 , Flemming Besenbacher 1
1 Interdisciplinary Nanoscience Center , University of Aarhus, Aarhus Denmark, 2 Department of Chemistry, University of Aarhus, Aarhus Denmark
Show Abstract9:00 PM - P16.26
One-Dimensional Lipid Bilayers on Carbon Nanotube Templates: Structure, Mobility, and Device Integration.
Shih-Chieh Huang 1 2 , Alexander Artyukhin 1 , Julio Martinez 1 3 , Donald Sirbuly 1 , Yinmin Wang 1 , Jiann-Wen Ju 2 , Pieter Stroeve 3 , Olgica Bakajin 1 , Aleksandr Noy 1
1 , Lawrence Livermore National Labs, Livermore, California, United States, 2 , UCLA, Los Angeles, California, United States, 3 , UC Davis, Davis, California, United States
Show Abstract9:00 PM - P16.27
Ink Jet Printing Carbon Nanotubes and Carbon Nanotube/DNA Heteromixtures.
Jan Sumerel 1
1 , FUJIFILM Dimatix, Santa Clara, California, United States
Show Abstract9:00 PM - P16.28
Development of a Nanocrystalline Diamond Electrode for Lactic Acid Detection.
Jessica Weber 1 , Sathyaharish Jeedigunta 2 , Ashok Kumar 1
1 Mechanical Engineering, University of South Florida, Tampa, Florida, United States, 2 Electrical Engineering, University of South Florida, Tampa, Florida, United States
Show Abstract9:00 PM - P16.29
WITHDRAWN 02/21/08 Enhanced Photocatalysis with Titanium Dioxide and Polyhydroxy Fullerenes.
Vijay Krishna 1 , Witcha Imaram 3 , Alexander Angerhofer 3 , Ben Koopman 4 1 , Brij Moudgil 2 1
1 Particle Engineering Research Center, University of Florida, Gainesville, Florida, United States, 3 Department of Chemistry, University of Florida, Gainesville, Florida, United States, 4 Department of Environmental Engineering and Sciences, University of Florida, Gainesville, Florida, United States, 2 Department of Materials Science and Engineering, University of Florida, Gainesville, Florida, United States
Show AbstractThursday, March 27WithdrawnPosterP16.29
9:00 PM - P16.3
Alternative Energy Sources for Tailor-made Carbon Nanotubes and Nanotube Composites.
Satoshi Ohara 1 , Akira Kondo 1 , Kazuyoshi Sato 1 , Hiroya Abe 1
1 Joining and Welding Research Institute, Osaka University, Ibaraki Japan
Show AbstractTo fine-tune the properties of materials, they can now be processed into uniform-size nanocrystals with spherical, wire, rod, tadpole shapes. Another trend in research aims at arranging individual nanocrystals into superlattices and investigating their unique properties. Despite these recent advances, controlling the shape, crystal structure, and surface characteristics of carbon nanotubes is still a difficult task. Here, we have investigated alternative energy sources for sophisticated tailor-made carbon nanotubes. The formation of unique carbon nanotubes with bent, buckled, twisted nanostructures was observed under a physically activated state. This paper also reported fabrication of carbon nanotube composites by aerosol reactor.
9:00 PM - P16.30
Highly Selective Detection of NO2 Pollutant in Atmospheric Air.
Sean Brahim 1 , Steve Colbern 1 , Robert Gump 1 , Leonid Grigorian 1
1 Sensors/Carbon Nanotubes, YTC America Inc., Camarillo, California, United States
Show AbstractThe detection and emission control of nitrogen dioxide, released by combustion, plants and automobiles is of great importance. Much effort has been made to develop sensors for monitoring the concentration of this pollutant in the environment at ppm levels or lower. For sensing such levels of gas pollutants, conventional gas sensors employing metal oxide thin films have serious limitations, particularly while operating at room temperature. While several reports have appeared that describe the use of both pristine and functionalized CNTs for NO2 detection, selectivity has been the plaguing issue as other interfering species can also adsorb onto the CNT surface to produce concomitant responses. In this work, the use of novel metal-CNT hybrid materials for discriminating and selectively detecting NO2 in a real matrix is described. The metal-CNT hybrid materials were found to exhibit strong capacitive responses to NO2 gas. These materials, when used as the active sensing layer in gas adsorption sensors, can selectively discriminate and identify NO2 gas impurity in atmosphere based on the very large change in capacitive response that is unique among gases present in atmosphere.
9:00 PM - P16.31
Optically Active Composites made of Silica and Carbon Nanotubes.
Satishkumar Chikkannanavar 1 , Stephen Doorn 2 , Andrew Dattelbaum 1
1 Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico, United States, 2 Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico, United States
Show Abstract9:00 PM - P16.32
Optical Properties of Hybrid Nanocomplexes of Quantum Dots and Single Wall Carbon Nanotubes.
Hyeonggon Kang 1 , Matthew Clarke 1 , Zhenping Zhou 2 , Jianyong Tang 1 , John Woodward 1 , Tinh Tinh Nguyen 2 , Jeeseong Hwang 1
1 Laser Application, NIST, Gaithersburg, Maryland, United States, 2 Materials Research and Construction Division, NIST, Gaithersburg, Maryland, United States
Show Abstract9:00 PM - P16.33
A CNT Electrode Ionization-Type Gas Sensor.
Alex Moser 1 , Leonid Grigorian 1
1 , YTC America, Inc., Camarillo, California, United States
Show AbstractAn ionization-type sensor using metal electrodes has been found to achieve ppm sensitivity level making this type of sensor useful for many gas sensing applications. This study explores the utility of replacing metal electrodes with a carbon nanotube (CNT) electrode. The rationale for this replacement is to take advantage of electrical field enhancement at CNT tips and thereby lower the operating voltage. Our results demonstrate that indeed the operating voltage could be decreased several times, from over kV to several hundreds volts. At the same time, the ppm level sensitivity was retained. The field enhancement factor, a measure of the efficiency of ionization of an analyte gas over a CNT vs. metal electrode, was investigated as a function of applied electrical potential, gas environment, and total gas pressure. CNT electrode degradation under severe sensor operating conditions was investigated using Raman spectroscopy and SEM/TEM data taken before and after device testing.
9:00 PM - P16.34
Attempts to Observe Hydrogen Spillover Phenomena on Carbon.
Hugo Romero 1 2 , Humberto Gutierrez 1 , Prasoon Joshi 2 , Peter Eklund 1 3
1 Department of Physics, Pennsylvania State University, University Park, Pennsylvania, United States, 2 Department of Electrical Engineering, Pennsylvania State University, University Park, Pennsylvania, United States, 3 Department of Materials Science & Engineering, Pennsylvania State University, University Park, Pennsylvania, United States
Show Abstract9:00 PM - P16.35
Composite Polymer Nanofibers with Carbon Nanotubes and Titanium Dioxide Particles with Enhanced Photocatalytic Activity.
Yachin Cohen 1 , Shahar Kedem 1 , Yaron Paz 1
1 Chemical Engineering Dept., Technion, Haifa Israel
Show AbstractComposite nanofibers containing Multi Walled Carbon Nanotubes (MWCNT) and nanometric TiO2 particles dispersed in poly(acrylonitrile) (PAN) were prepared by the electrospinning (ES) technique. Imaging the solutions used for electrospinning by cryo-transmission electron microscopy, showed excellent dispersion of both nanotubes and nanoparticles in PAN/dimethyl-formamide solution, and showed that the titania nanoparticles spontaneously attach to the CNT surface. The fabricated nanofibers, the diameters of which were in the 20-200 nm range, contained well-oriented nanotubes and spherical TiO2 nanoparticles in close proximity. The presence of carbon nanotubes stabilizes the polymer nanofibers against photodegradation by UV radiation, in comparison with nanofibers composed only of PAN and TiO2. The photocatalytic activity of mats composed of electrospun nanofibers in decomposition of acetone and carbon tetrachloride by exposure to UV radiation was investigated using a special reaction vessel attached to an infra-red spectrometer. Enhanced photocatalytic activity was observed , and may be explained by enhanced electron-hole separation by the CNT/titania combination.
9:00 PM - P16.36
Size Dependent Morphology and Mechanics of Carbon Nanotube Ropes.
Moneesh Upmanyu 1 2
1 Engineering Division, Materials Science Program, Colorado School of Mines, Golden, Colorado, United States, 2 Bioengineering and Life Sciences Program, Colorado School of Mines, Golden, Colorado, United States
Show Abstract9:00 PM - P16.5
Nanopipette Catalyst Writing for Single-Walled Carbon Nanotube Growth.
Badr Omrane 1 , Chris Papadopoulos 1
1 Electrical and Computer Engineering, University of Victoria, Victoria, British Columbia, Canada
Show AbstractDue to their mechanical, thermal, chemical and electrical properties single-walled carbon nanotubes (SWCNTs) are considered important materials for enhancing electronic devices at the nanoscale level [1]. Nevertheless, many challenges remain including the role of catalyst shape and size on the growth direction of the SWCNTS. Catalysts deposited in liquid form have often been used via photolithographic patterning to grow SWCNT patterned areas [2,3]. However, the amount of catalyst used is typically quite large compared to the actual amount of SWCNTs produced during growth. In this work, we investigate the effect of liquid catalyst size and geometry on the growth process of SWCNTs. Different concentrations of alumina-supported iron and ferritin catalysts were patterned on silicon and silicon dioxide wafers using a nanoscale pipette. Quartz and borosilicate glass nanopipettes of approximately 50 and 100 nm openings respectively and mounted to a scanning probe microscope were employed. Catalyst geometry and size as a function of drawing parameters including contact time, applied force and tip speed were studied using patterns including as sets of straights lines and arrays of dots. The growth process was performed using chemical vapor deposition (CVD) with a mixture of methane (CH4), hydrogen (H2) and acetylene (C2H2) at 800-900oC. In the case of ferritin, additional steps of oxidation in air and cooling were required in order to prepare the catalyst for SWCNT growth. The effect of liquid catalyst size and concentration on SWCNT yield was also examined. Scanning electron microscope and atomic force microscope characterization of the patterning show that the size and shape of the catalyst can be controlled precisely down to the nanoscale level. The drawing speed tends to change the height of the catalyst whereas contact time and applied force were most important when drawing arrays of catalyst dots. The type of liquid catalyst solvent along with substrate hydrophobicity play major roles in determining catalyst geometry during the patterning process due to the different contact angles with the surface. We were able to draw multiple arrays of lines and dots in a controllable manner. The technique presented allows nanoscale catalyst patterns of almost arbitrary geometry to be created for SWNCT growth, in a simple and inexpensive manner. [1] P. Avouris et al., Proc. IEEE 91, 1772-1784 (2003). [2] J. Kong et al., Nature 395, 878-881 (1998). [3] N. R. Franklin et al., Adv. Mater. 12, 890-894 (2000).
9:00 PM - P16.6
Weak Polyelectrolyte Control of Carbon Nanotube Dispersion in Water.
Jaime Grunlan 1 2 3 , Lei Liu 3
1 Mechanical Engineering, Texas A&M University, College Station, Texas, United States, 2 Chemical Engineering, Texas A&M University, College Station, Texas, United States, 3 Materials Science and Engineering, Texas A&M University, College Station, Texas, United States
Show Abstract9:00 PM - P16.7
Shaping the Interface of Carbon Nanotubes-reinforced Polymer Composites Through in-situ Polymerization.
Shiren Wang 1 , Richard Liang 2 , Ben Wang 2 , Chuck Zhang 2
1 Industrial Engineering, Texas Tech Univ, Lubbock, Texas, United States, 2 High-Performance Materials Institute, Florida State University, Tallahassee, Florida, United States
Show Abstract9:00 PM - P16.8
The Use of Supercritical Fluids for Selective Transport, Deposition and Assembly of Nanocrystals.
Carlos Fernandez 1 , Emily Hoppes 1 , Jacky Bekahzi 1 , Marvin Warner 1 , Raymond Addleman 1
1 Energy and environmental directorate, Pacific Northwest National Laboratory, richland, Washington, United States
Show Abstract9:00 PM - P16.9
Chemical Sensors from Graphene Oxide.
Jeremy Robinson 1 , Zhongqing Wei 1 , F. Perkins 1 , Paul Sheehan 1 , Eric Snow 1
1 , Naval Research Laboratory, Washington, District of Columbia, United States
Show Abstract
Symposium Organizers
Li-Chyong Chen National Taiwan University
John Robertson Cambridge University
Zhong Lin Wang Georgia Institute of Technology
David B. Geohegan Oak Ridge National Laboratory
P17: Process and Assembly II
Session Chairs
Zhongfan Liu
John Robertson
Friday AM, March 28, 2008
Room 2005 (Moscone West)
9:00 AM - **P17.1
Nanoelectronics and Macroelectronics Based on Massively Aligned Single-walled Carbon Nanotubes.
Chongwu Zhou 1
1 Dept. of Electrical Engineering - Electrophysics, University of Southern California, Los Angeles, California, United States
Show AbstractSynthesis and manipulation of massively aligned single-walled carbon nanotubes are important steps for various applications, including high performance carbon nanotube integrated circuits and chemical / biosensor arrays. Previously we have successfully developed the synthesis of massively aligned carbon nanotube arrays on a-plane sapphire and quartz substrates, with nanotube lengths exceeding 200 um and diameters ~ 1-2 nm. In this talk we will present our recent advance on transfer printing of aligned nanotubes and integrated carbon nanotube devices and circuits. A facile approach has been developed to transfer the aligned nanotubes from the original sapphire/quartz substrates to virtually any other substrates, including glass, silicon, polymer sheets, and even fabrics. Based on the aligned nanotubes, we have successfully demonstrated high-performance transistors and integrated circuits using multiple parallel nanotubes for high transconductance and improved uniformity. In addition, we have obtained sophisticated carbon nanotube networks by performing multiple transfers of nanotubes onto the same substrate at several orientations. Furthermore, based on transferred nanotube arrays on various substrates, we have successfully demonstrated wearable nanotube transistors with on/off ratios ~ 105, and chemical sensors for low-concentration NO2 and 2,4,6-trinitrotoluene. This transfer printing technique may prove valuable for nanotube flexible electronics, and hybrid integration of aligned nanotubes with silicon electronics.
9:30 AM - P17.2
3D Pick-and-Place of Carbon Nanotubes Using Shape-optimized Grippers.
Peter Boggild 1 , Kenneth Carlson 1 , Ozlem Sardan 1 , Volkmar Eichhorn 3 , Karin Andersen 1 , Dirch Petersen 1 , Ian Y. Y. Bu 4 , Ken B. K Teo 4 , William Milne 4 , Sergej Fatikow 3 , Ole Sigmund 2
1 MIC - Department of Micro and Nanotechnology, Technical University of Denmark, Kgs. Lyngby Denmark, 3 Division Microrobotics and Control Engineering, University of Oldenburg, Oldenburg Germany, 4 Electrical Engineering Division, University of Cambridge, Cambridge United Kingdom, 2 MEK - Department of Mechanical Engineering, Technical University of Denmark, Kgs. Lyngby Denmark
Show Abstract9:45 AM - P17.3
Selective Placement of Carbon Nanotubes.
Ali Afzali 1 , James Hannon 1 , Julie Bardecker 1 , George Tulevski 1 , Teresita Graham 1
1 T. J. Watson Research Center, IBM Research Division, Yorktown Heights, New York, United States
Show AbstractCarbon nanotubes (CNTs) are playing an increasing important role in development of nanotechnology. For example, filed-effect transistors incorporating CNTs as channel have demonstrated superior device performance compared to conventional Si devices. However, a major barrier to large-scale integration of CNT devices in circuits is lack of control in placement and orientation of nanotubes on substrates. In this talk, we present several approaches to selective placement of CNTs on an oxide substrates. These approaches include , functionalization of CNTs for directed assembly on metal oxide, use of photosensitive monolayers to divide the surface into hydrophilic and hydrophobic regions and assembly of CNTs on prepatterned substrates
10:00 AM - P17.4
Nanoprober-Based Pick-and-Place Process for Site-Specific Characterization of Individual Carbon Nanotubes.
Thomas Hantschel 1 , Peter Ryan 1 , Saku Palanne 1 , Olivier Richard 1 , Kai Arstila 1 , Anne Verhulst 1 , Francesca Clemente 1 , Hugo Bender 1 , Wilfried Vandervorst 1
1 , IMEC, Leuven Belgium
Show AbstractCarbon nanotubes (CNT) are currently being evaluated as interconnects in nanoelectronics technology. For this, small diameter and high-density CNTs must be grown inside small contact holes. The development and optimization of such a fabrication process requires the local characterization of individual CNTs with regard to structure, morphology, electrical properties and defects. The widely-used dispersion method does not work for this application as it requires many CNTs to be present on the substrate, it cannot differentiate between CNTs coming from different places of the wafer and it strongly suffers from bundling effects. An analysis approach is highly desired which allows to select an individual CNT from an arbitrary place of a substrate and to carry out different kinds of analysis methods on the same CNT. Therefore, we have developed a pick-and-place process which allows to pick up a single CNT from the desired place of the wafer and to place it on another substrate on a specific location where the CNT can be characterized by different analysis methods. The key element of our process is the combination of scanning electron microscopy (SEM) with nanomanipulation. Furthermore, we use special welding and deposition steps and marking of the CNT locations. Our paper is explaining how one can pick up and place down a CNT from a specific site and we show that this CNT can be analyzed by different techniques such as transmission electron microscopy (TEM), RAMAN, electrical measurements and atomic force microscopy (AFM). We demonstrate how this approach can be used to analyze CNTs grown in small contact holes. The developed pick-and-place approach overcomes the challenge for site-specific analysis of CNT interconnects and strongly facilitates the overall CNT analysis. The pick and place step was done by a nanoprober consisting of a Philips XL 30 SEM, a Kleindiek 4-point nanomanipulator and a Keithley 4200 parameter analyzer. The CNTs used in this study were grown inside 150-300 nm contact holes using Ni, Co and Fe catalyst. The selective removal of the CNT was realized by either welding the CNT against a tungsten probe tip using a focused electron beam or electrical burn-through of the CNT. The CNTs were afterwards deposited onto marked grids coated with a perforated carbon film. Macroscopic marks and the unique perforation pattern were used to locate the deposited CNTs during the analysis. Many individual CNTs were removed from different contact holes, were deposited on specific locations of a marked grid and could be easily relocated in a TEM for inspection. We combined different types of analysis on the same CNT such as electrical measurements & TEM and TEM & RAMAN. We applied the pick-and-place approach to both multi-wall and single-wall CNTs.
10:15 AM - P17.5
Theory of Superplasticity and Atomic Relaxation in Nanotubes and Fullerenes.
Feng Ding 1 , Kun Jiao 1 , Yu Lin 1 , Jianyu Huang 2 1 , Boris Yakobson 1
1 ME&MS, Rice University, Houston, Texas, United States, 2 CINT, Sandia National Laboratories, Albuquerque, New Mexico, United States
Show Abstract10:30 AM - P17.6
Carbon Nanotube Based Photocathodes.
Pierre Legagneux 1 , Ludovic Hudanski 1 , Nicolas Le Sech 1 , Ken Teo 2 , Eric Minoux 1 , Laurent Gangloff 2 , Jean-Philippe Schnell 1 , Stephane Xavier 3 , Costel Cojocaru 3 , John Robertson 2 , William Milne 2 , Didier Pribat 3
1 Nanocarb, Thales R&T, Palaiseau France, 2 Electrical Engineering Division, University of Cambridge, Cambridge United Kingdom, 3 LPICM, Ecole Polytechnique, Palaiseau France
Show AbstractP18: Novel Properties: Electronic, Spin and Photoconductivity
Session Chairs
Li-Chyong Chen
David Geohegan
Friday PM, March 28, 2008
Room 2005 (Moscone West)
11:15 AM - **P18.1
Axial Band Structure Engineering of Single-Walled Carbon Nanotubes Targeting Electronic Devices.
Zhongfan Liu 1
1 , College of Chemistry and Molecular Engineering, Peking University, Beijing China
Show AbstractWe are working along with a concept of axial band structure engineering of SWNTs for the purpose of fabricating practical integration devices. Starting from a parallel array of ultralong SWNTs, the local energy band structure of an individual nanotube is modulated with various physical or chemical methods along tube axis. We report herein our recent progress targeting the related technological challenges. The first topic concerns the temperature-oscillation CVD growth of SWNTs. By oscillating the temperature during growth, we found that the tube diameter and chirality are changed even though the catalyst particle remained the same. With increasing the growth temperature, the tube diameter becomes thinner or vise versa. This leads to the formation of intratube nanojunctions. The second topic concerns the transfer-print technique we developed for handling nanomaterials such as SWNTs for the purpose of fabricating nanoscale devices. By using a polymer film as the transfer-print mediator, we have successfully transferred the CVD grown SWNTs arrays onto any surfaces in a well controlled manner and a mild condition. This makes it possible to modulate the local band structures of SWNTs by transferring onto the pre-designed surfaces modified with organic monolayers. Further measurements indicated that the electrical contacts formed in such a transfer-print process are well enough for fabricating high-performance FETs, CMOS inverters, and crossbar architectures. We found that such a transfer-print technique is also applicable to nanowires and even nanostructures. In addition, the bending and torsional performances of carbon nanotubes have been examined with the aid of AFM manipulation. We found that the nanotubes can be classified into two groups in response to bending deformation: Buckling mode I and Buckling mode II . Mode I corresponds to a single walled or large diameter multiwalled tube with thin wall, showing one critical angle for buckle formation. On the other hand, Mode II corresponds to a multiwall or small diameter single walled tube, showing a gradual buckling with two critical angles for buckle starting and ending, respectively. For a torsional strain on the ultralong SWNTs, the change of electronic transition energy Eii strongly depends on the tube chirality, following a family pattern.
11:45 AM - P18.2
Terahertz Time-Domain Detection of Ballistic Electron Resonance in a Single-walled Carbon Nanotube.
Zhaohui Zhong 1 , Nathaniel Gabor 1 2 , Jay Sharping 4 , Alexander Gaeta 1 3 , Paul McEuen 1 2
1 Center for Nanoscale Systems, Cornell University, Ithaca, New York, United States, 2 Laboratory of Atomic and Solid-State Physics, Cornell University, Ithaca, New York, United States, 4 School of Natural Sciences, University of California at Merced, Merced, California, United States, 3 School of Applied and Engineering Physics, Cornell University, Ithaca, New York, United States
Show AbstractUnderstanding the terahertz (~ 100 GHz to 10 THz) electrical properties of nanomaterials is of relevance both to the fundamental physics of low-dimensional electron transport and to the operation of next-generation smaller and faster electronics. We perform the first time-domain terahertz electrical measurements of a prototypical nanoscale device: a single-walled carbon nanotube transistor. By integrating a terahertz source and a carbon nanotube transistor on the same substrate, high frequency signals are generated locally by the source and detected locally by the nanotube transistor. Significantly, a ballistic electron resonance is directly observed with a picosecond-scale period corresponding to the roundtrip transit of an electron along the nanotube. The electron velocity is measured to be constant and equal to the Fermi velocity, showing that the single-particle excitations of the nanotube instead of the plasmon mode dominate the high frequency response. These results demonstrate a powerful new tool for directly probing picosecond electron motion in nanostructures. Further, they show that carbon nanotubes, with their constant Fermi velocity, are uniquely suited for creating micron-scale terahertz resonators.
12:00 PM - P18.3
Dielectric Response of SWNTs and its Application in Assaying for Metallic Content in SWNT Mixtures.
Wei Lu 1 , Yao Xiong 1 , Dan Wang 1 , Liwei Chen 1
1 Chemistry and Biochemistry, Ohio University, Athens, Ohio, United States
Show AbstractFriday, March 28Transferred Poster P8.14 to P18.3 @ 11:00 AMDielectric Response of SWNTs and its Application in Assaying for Metallic Content in SWNT Mixtures. Liwei Chen
12:15 PM - P18.4
Modeling Spin Qubit in Carbon Peapods.
Ling Ge 1 , Barbara Montanari 2 , John Jefferson 1 3 , David Pettifor 1 , Nicholas Harrison 2 , Andrew Briggs 1
1 Materials, Oxford University, Oxford United Kingdom, 2 , STFC Rutherford appleton Laboratory, Oxford United Kingdom, 3 Sensors and Electronics Division, QinetiQ, Malvern United Kingdom
Show Abstract12:30 PM - P18.5
Infrared Detection and Electron Transport Characteristics of a Carbon nanotubes/Si Heterodimensional Heterostructure.
Teng-Fang Kuo 1 , Marian Tzolov 2 , Daniel Straus 1 , Jimmy Xu 1
1 , Brown University, Providence, Rhode Island, United States, 2 , Lock Haven University of Pennsylvania, Lock Haven, Pennsylvania, United States
Show Abstract12:45 PM - P18.6
Photoconductive Lifetimes of Carbon Nanotubes Films.
Katherine Hurst 1 , Richard Ahrenkiel 2 , Steve Johnston 2 , Anne Dillon 2 , Lara Roberson 1 , John Lehman 1
1 , National Institute of Standards and Technology, Boulder, Colorado, United States, 2 , National Renewable Energy Laboratory, Golden, Colorado, United States
Show AbstractThe photoconductive recombination lifetimes of carbon nanotube (CNT) thin films as a function of wavelength are measured by a resonant-coupled photoconductive decay (RCPCD) method (1). The carrier recombination lifetime is a fundamental property of carbon nanotubes that is typically determined by contact-based techniques or spectroscopic methods. The RCPCD is a non-contact measurement based on a pump-probe technique in which an optical pump and a low-frequency microwave probe are employed. It is well suited to characterization of bulk and extrinsic material properties. Our results demonstrate the role of purification and the effect of the interaction of nanotubes and polymers in thin films of multiwalled carbon nanotube and single-walled carbon nanotubes. Possible mechanisms describing the interaction of photoexcited carriers in the nanotube polymer composites will be discussed. Finally, we report the wavelength dependence of photoconductive lifetimes. Raman spectroscopy and UV-VIS absorption measurements provide further identification and characterization of nanotube samples to enable correlation of nanotube properties with the efficiency of charge transport.(1) R.K. Ahrenkiel, S.W. Johnston Mater. Sci. Eng. B 102 (2003) 161