Symposium Organizers
Martin L. Green National Institute of Standards & Technology
Ichiro Takeuchi University of Maryland
Tony Chiang Intermolecular, Inc.
Johan Paul Flamac
Symposium Support
Flamac
Intermolecular Corp
G1: New Combinatorial Methods and Applications
Session Chairs
Wednesday PM, April 15, 2009
Room 2009 (Moscone West)
2:30 PM - **G1.1
High-Throughput IR-laser Deposition and Laser Microscope Imaging of Ionic Liquids in Vacuum
Yuji Matsumoto 1 , Shingo Maruyama 1
1 Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
Show Abstract There has been lately a growing interest in ionic liquids (ILs), which are characterized by low temperature molten salts and their no measurable vapor pressure. It is this feature that enables to successfully apply the powerful ultra-high-vacuum (UHV) techniques of the surface scientist not only to the basic studies of the ILs [1,2], but also to the materials processings with it [3]. For further applications of these ILs to the UHV process, highly is required some of preparation techniques of the ILs in vacuum for a continuous UHV operation. For this purpose, we have established an IR-laser deposition technique for ILs, compatible with the conventional combinatorial pulsed laser deposition system [4]. A pulsed IR laser beam is introduced into a vacuum chamber through a quarts window, focused onto the IL embedded with a Si powder, which assists absorption of the IR laser. The deposition rate reaches as low as 0.03nm/pulse on a nano scale. This technological achievement has come to enable the preparation of a binary continuous mixture of ILs in a similar way of the so-called composition spread technique. That is, the binary mixtures of the ILs with different mix ratios were prepared on a single substrate by an alternate deposition of two different ILs, being synchronized with a moving mask. For the high-throughput analysis of this binary continuous mixture of the ILs, we employ a UHV-laser microscope, which is directly combined with the IR laser deposition system, for investigating a thermal evaporation behavior of these mixtures in vacuum. In my presentation, the high-throughput deposition process of the ILs will be demonstrated, together with some of the UHV-laser microscope imaging data for their thermal evaporation process, and its potential applications will be discussed as well. References: [1] E. F. Smith et al., Langmuir 22, 9386 (2006). [2] S. Kuwabata et al., Chemistry Letters 35, 600 (2006). [3] T. Torimoto and S. Kuwabata et al.,Appl. Phys. Lett. 89 243117 (2006). [4] S. Yaginuma et al., Appl. Phys. Express 1, 015005 (2008).
3:00 PM - **G1.2
High-Productivity Combinatorial PVD and ALD Workflows for Semiconductor Logic & Memory Applications.
Imran Hashim 1 , Chi-I Lang 1 , Hanhong Chen 1 , Jinhong Tong 1 , Monica Mathur 1 , Prashant Phatak 1 , Ron Kuse 1 , Sandra Malhotra 1 , Sunil Shanker 1 , Xiangxin Rui 1 , Yun Wang 1
1 , Intermolecular, San Jose, California, United States
Show AbstractWith materials innovation driving recent logic and memory scaling in the semiconductor industry, High-Productivity Combinatorial™ (HPC) technology can be a powerful tool for finding optimum materials solutions in a cost-effective and efficient manner. This paper will review unique HPC wet processing, physical vapor deposition (PVD), and atomic layer deposition (ALD) capabilities that were developed, enabling site-isolated testing of multiple conditions on a single 300mm wafer. These capabilities were utilized for exploration of new chalcogenide alloys for phase change memory, and for metal gate and high-K dielectric development for high-performance logic. Using an HPC PVD chamber, a workflow was developed in which up to 40 different precisely controlled GeSbTe alloy compositions can be deposited in discrete site-isolated areas on a single 300mm wafer and tested for electrical & material properties, using a custom in-situ high-throughput sheet-resistance measurement setup, to get very accurate measurements of the amorphous – crystalline transition temperature. We will review how resistivity as a function of temperature, crystallization temperature, final and intermediate (if any) crystalline phases were mapped for a section of the GeSbTe phase diagram, using only a few wafers. Another area where HPC can be very valuable is for finding optimum materials for high-k dielectrics and metal gates for high-performance logic transistors. Assessing the effective work-function (EWF) for a given high-k dielectric metal-gate stack for PFET and NFET transistors is a critical step for selecting the right materials before further integration. One way to obtain EWF is by using a terraced oxide wafer with different SiO2 thickness bands underneath the high-k dielectric. We report a HPC workflow using our wet, ALD & PVD capabilities, to quickly assess EWF for multiple different high-k dielectrics and metal gate stacks. This workflow starts with a HPC wet etch of thermal silicon oxide, creating different oxide thicknesses 1–10nm in select areas of the same substrate. This is followed by atomic layer deposition of a high-k dielectric film such as HfO2. Next, a metal e.g., TaN is deposited through a physical mask or patterned post-deposition to complete the formation of MOS capacitors. The final step is C-V measurements of these MOS capacitors and C-V modeling to extract Vfb, high-k dielectric constant, EOT, and EWF from Vfb vs EOT plot. This workflow was used to extract EWF for a TaN metal gate with an ALD HfO2 high-k dielectric using a metal-organic precursor. We will discuss how EWF for this system was affected by annealing post-dielectric deposition & post-metallization, different annealing temperatures & ambients, Hf pre-cursors and interfacial cap layers e.g., La2O3 & Al2O3. Finally, we will also discuss more advanced versions of this workflow where the high-k dielectric and metal gate is also varied on the same wafer using HPC versions of ALD & PVD chambers.
3:30 PM - G1.3
High-Throughput Measurements for Materials Informatics and Materials Design.
Ji-Cheng Zhao 1 , Xuan Zheng 2 , David Cahill 2
1 , The Ohio State University, Columbus, Ohio, United States, 2 Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States
Show AbstractThis talk will illustrate high-throughput measurements for fast establishment of materials databases for accelerated materials design and discovery. The methodology is based on a simple idea of taking advantage of the compositional gradients and phase formation in diffusion couples and diffusion multiples to perform localized property measurements. Such measurements require a new suite of materials property microscopy tools with micron-scale resolution, but would greatly accelerate the efficiency of data gathering as compared to traditional measurements on individual alloys. The local equilibrium at the phase interfaces allows fast evaluation of phase diagrams which are essential input to CALPHAD modeling. Micron-scale resolution tools were developed in recent years to measure thermal conductivity and coefficients of thermal expansion (CTE). The power of application of these tools on diffusion multiple samples to establish materials property databases will be illustrated using several examples. For instance, a micro-scale thermal conductivity technique can be used to study order-disorder transformation, site preference in intermetallic compounds, solid-solution effect on conductivity, and compositional point defect formation. These tools can be applied not only to accelerate the development of structural materials, but also to discover new functional materials. They will greatly accelerate the critical data gathering for the materials informatics.
3:45 PM - G1.4
Novel Crystallization Temperature Measurement Method for Combinatorial Evaluation using Infrared Thermography.
Yuko Aono 1 , Seiichi Hata 2 , Junpei Sakurai 2 , Akira Shimokohbe 2
1 Mechano-Micro Engineering, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan, 2 Precision & Intelligence Laboratory, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
Show AbstractIn combinatorial method, combinatorial evaluation of thin film library has not been established enough, so efficiency of searching by this method is limited. One of property which has not been available combinatorial evaluation is crystallization temperature (Tx). Conventionally, Tx is measured using differential scanning calorimeter (DSC), but it is impossible to apply to the thin film library. Because its one sample size is 1×1 mm, thickness is several micrometers, and 1,089 samples (33columns×33 rows) are integrated on one library, so the samples are too small to measure using DSC. In this study, an alternative method using infrared thermography is presented for combinatorial evaluation of Tx. This device detects infrared energy radiated from an object and its temperature can be calculated using its own emissivity.In crystallization point, electrical resistivity change is lead with structure change, and this derives emissivity change. Low electrical resistivity means less free electron that is low reflectivity and high emissivity. In heating test, while emissivity keeps constant, T-Ta curve (T: true sample temperature, Ta: apparent temperature measured by thermography) gradient is constant, but the point of Tx, T-Ta curve gradient changes by change of emissivity. Therefore transformation point can be detected by T-Ta curve gradient change. This method can be applied to thin film library, because the method requires only observation of sample surface.PtSi and PdCuSi amorphous alloys were employed to confirm this method. First, homogeneous amorphous alloy thin films were deposited on alumina wafer (20×20mm). Each of these samples was then heated in vacuum chamber with monitoring infrared images and electrical resistivity, in-situ. Obvious emissivity change could be detected at the same temperature of electrical resistivity change. This temperature also agrees enough with DSC results. In case of Pt67Si33, emissivity change was detected at 511K, and DSC result shows Tx at 516K, there is only 5K error between these values. At this temperature, both electrical resistivity and emissivity decreased and it agrees with the theory. Sample crystallization was confirmed after heating test by X-ray diffraction.Measurement on the thin film library was then considered. A quarter thin film library was used, 256 samples (16×16) are integrated and each sample size is 1×1mm separated 0.2mm grid made by sputtering on alumina wafer. For first inspection, all samples were same composition Pd77Cu6Si17 amorphous alloy. Every 3×3 samples, center sample were blank, i.e. alumina surface, its emissivity is stable so the surface indicated reference temperature of around samples. Alumina emissivity was calibrated using a thermo couple on the sample wafer. 184 samples in the all samples were measured at one time, Tx can be detected in all 184 samples and these value errors ranged in 15K. Therefore, this method has a great of potential in combinatorial method.
4:30 PM - **G1.5
Workflow Optimization for Materials Research and Development Using Combinatorial Methodology.
Scott Andrews 1 , Zack Fresco 1 , Nitin Kumar 1 , Sandeep Mariserla 1 , Shuogang Huang 1 , Jeffrey Lowe 1 , Anh Duong 1 , Nikhil Kalyankar 1 , Jinhong Tong 1 , George Mirth 1 , Chi-I Lang 1
1 , Intermolecular, San Jose, California, United States
Show AbstractAs the semiconductor industry moves past the 45 nm node, innovation of new materials and processes are playing a much larger role in the performance gains relative to scaling improvements. To develop these new materials, an increasing number of elements are being explored in a wider variety of combinations. As such, improvements are requiring an improved ability to run many more experiments in shorter timelines. Existing research and development methods have worked well in the past but are increasingly showing their limitations as the increased number of resources required becomes prohibitive. Combinatorial technology has been developed to address these issues. Specifically, it allows a faster turnaround time with multiple variables and conditions being tested on each wafer. One tool that has been developed for wet chemistry experiments can produce 192 experiments per 300 mm wafer. This increase in efficiency per wafer allows many more experiments to be run with fewer resources. The challenge with such a method is the large amount of data generated. This issue is compounded when multiple metrology and electrical measurements are made on each reaction site. To address this issue, a database and analysis package has been developed to acquire data from measurement tools and correlate the results with the corresponding experimental conditions on each wafer. This allows for faster and more efficient research cycles.Since a large number of conditions can be tested rapidly, a pipeline of materials can be evolved in which different materials are at different stages of screening and scale-up. An important addition for this purpose includes the use of feed-back and feed-forward information transfer. As one advances new chemistries through the optimization pipeline, chemicals in earlier stages of testing can provide information on how to test a later process. For example, if a late-stage chemical shows that a particular component does not allow for sufficient reproducibility then any chemical containing this component that is waiting for early-stage testing can be immediately eliminated thereby saving time and resources. Similarly, while the first chemical to be tested advances to mid-stage testing, many more chemicals will have completed early-stage testing. As such, a more complete understanding of the classes of promising chemicals can be identified by the time the first chemical reaches late-stage testing. This new knowledge can be used to prioritize the most promising set of chemicals in the final stages of testing. To do this efficiently, the Informatics database and analysis package combines data from a wide range of processing and measurement tools and then analyzes the data with a range of statistical and analysis routines. By combining combinatorial tools and well designed experiments with a robust data collection and analysis system can greatly improve the efficiency and effectiveness of semiconductor research and development.
5:00 PM - **G1.6
Integration of Miniature Cluster Chamber Modules for Combinatorial Material Exploration and Device Fabrication.
Kenji Itaka 1 , Masao Katayama 1 , Mikk Lippmaa 1 , Toyohiro Chikyow 2 , Tsuyoshi Ohnishi 2 , Hideomi Koinuma 1
1 , The University of Tokyo, Kashiwa, Chiba, Japan, 2 , National Institute for Materials Science, Tsukuba, Ibaraki, Japan
Show AbstractFor combinatorial exploration of device materials, combination samples of combinatorial library of each layer are required. In fabrication of electronic functional devices, it is indispensable to make various thin film layers for semiconducting active layer, dielectric layers, electrodes, which are composed of oxides, nitrides, metals and so on. For the fabrication of these layers, it is necessary to use such various thin-film fabrication techniques, as thermal evaporation, sputtering and pulse laser deposition.On the other hand, the interface and surface state of each layer change dramatically by exposure to the air. Vacuum conveyance of sample library without exposure to the air is the best solution to maintain the condition of interfaces and surfaces of each layer. To build up multipurpose thin-film fabrication system without air exposure, we are developing integrated system, which is composed of several small and exchangeable cluster chambers with combinatorial mechanism and common transfer port. In integration of many cluster-type chambers, the use of conventional transfer rods interferes with integration of these cluster chambers. We developed a flexible transfer rod, which can transfer a library in each six modules in vacuum. The developed system can equip with 6 small modules of thin-film fabrication modules or measuring modules, in the area with a radius of 1m.Developed special transfer rods can transfer a library in each six modules in vacuumThe connected system of the chamber modules with different functions will be useful for combinatorial exploration of devices with complicated interfaces.
5:30 PM - G1.7
Advances in Synchrotron-based X-ray Microprobe Techniques as Enablers of Solar Energy Research
Sarah Bernardis 1 , Mariana Bertoni 2 , Sirine Fakra 3 , David Fenning 2 , Steve Hudelson 2 , Matthew Marcus 3 , Bonna Newman 2 , Joseph Sullivan 2 , Tonio Buonassisi 2
1 Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 2 Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 3 Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California, United States
Show AbstractWe summarize recent developments of synchrotron-based X-ray microprobe techniques, which have directly contributed to advances in solar cell material and device technology. By way of example, the X-ray Microprobe Beamline 10.3.2 of the Advanced Light Source of Lawrence Berkeley National Laboratory is discussed in detail. We focus primarily on three enabling components:(1) Hardware features, which improve sensitivity and increase the speed of data acquisition. A virtual source (toroidal mirror) provides improved beam stability and adjustable spot size. Slewscan feature, enabling <50 ms/pixel data acquisition coupled to fast detector readout. High-sensitivity large-area detector with thin window for detecting elements as low-Z as silicon.(2) Software tools, which are modular, easy to use, and rapidly perform data analyses and assess correlations. Labview-based mapping and correlation software enables near simultaneous data acquisition and analysis (e.g., tricolor mapping, inter-element correlation and masking). The running software includes facilities for automatic acquisition of XAS and MCA data from a number of spots without the need for human intervention. In addition, easy-to-use EXAFS pre-processing software includes Fourier filtering, linear combination fitting and principal component analysis. All tools are available as stand-alone items for off-site data analysis.(3) Technique development, such as an in-situ sample stage, which enables measurements under realistic device processing conditions. The implementation of the in-situ stage allows for high temperature, controlled-environment experiments that elucidate fundamental kinetics and thermodynamics of defects during solar cell processing. In addition, proposed defect engineering processes can be observed in real time, allowing for near-instantaneous feedback and evaluation of their effectiveness.We demonstrate the impact of these technique developments by summarizing recent scientific advances in solar energy research, in which synchrotron-based analytical X-ray microscopy has played a pivotal role. In particular, we discuss how EXAFS was employed to resolve the controversy over the chemical state of metal precipitates in multicrystalline silicon solar cells and feedstock materials, and how this understanding presented new possibilities for defect engineering. Most recently, the discovery of mixed-metal silicide precipitates has opened a new field: understanding and harnessing defect interactions during solar cell processing.
5:45 PM - G1.8
A Combinatorial and Distributed Approach to Discovering Materials for Water Photoelectrolysis
Bruce Parkinson 1 , Robert Herrick 2 , Aaron Wolfe 2 , Jennifer Schuttlefield 1
1 Chemistry, University of Wyoming, Laramie, Wyoming, United States, 2 Chemistry, Colorado State University, Fort Collins, Colorado, United States
Show AbstractThe increasing need for carbon free energy has focused renewed attention on solar energy conversion. Although photovoltaics offer an attractive method for the direct conversion of solar energy to electricity, it does not directly produce stored energy or fuels. Direct photoelectrolysis of water has the advantage of converting solar energy directly to hydrogen, an ideal non-carbon energy carrier, by replacing both a photovoltaic array and an electrolysis unit with one potentially inexpensive device. Semiconducting metal oxides could potentially be stable under illumination in an aqueous electrolyte for many years making them the most promising materials for solar water photoelectrolysis. The problem is that no known oxide semiconductor can efficiently carry out this process. We have developed a simple, high-throughput combinatorial approach to prepare and screen many complex oxides for water photoelectrolysis activity. The approach uses ink jet printing of overlapping patterns of metal oxide precursors, metal nitrate salts, onto conductive glass substrates. Subsequent firing produces metal oxide phases that are screened for photoelectrolysis activity by measuring photocurrents produced by scanning a laser over the printed patterns in aqueous electrolytes. We have prepared and tested inexpensive printing and screening kits based on Lego Mindstorms® to distribute to undergraduate students and eventually to high schools. We have termed this approach distributed research. Progress in the development and testing of these kits will be presented.
Symposium Organizers
Martin L. Green National Institute of Standards & Technology
Ichiro Takeuchi University of Maryland
Tony Chiang Intermolecular, Inc.
Johan Paul Flamac
G3: Hydrogen Storage Materials and Materials Informatics
Session Chairs
Jason Hattrick-Simpers
J.-C. Zhao
Thursday PM, April 16, 2009
Room 2009 (Moscone West)
2:30 PM - **G3.1
High-Throughput Measurements of Materials for Hydrogen Storage.
Leonid Bendersky 1
1 Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland, United States
Show AbstractCombinatorial thin films provide an opportunity for studying a variety of properties over a wide range of compositions and microstructures on a single substrate, allowing substantial acceleration of both the fabrication and study of materials and their properties. Considering technological needs for materials able to absorb/desorb large quantities (> 7 wt%) of hydrogen at low temperatures and pressures, it is highly desirable to develop combinatorial methods for high-throughput characterization of hydrogenation process.We will report on efforts here at NIST to develop a well standardized optical techniques, such us IR emissivity imaging and Raman and FTIR spectroscopies, to be used as a bench-top high-throughput characterization technique for combinatorial studies of hydrogen storage materials. Calibration of the optical measurements is realized through the use of in-situ prompt gamma activation analysis (PGAA) and volumetric Sievert-type measurements, which measures quantitatively the amount of hydrogen that is contained within a sample. By calibrating IR emissivity, Raman and FTIR signals the relationship between the optical intensity and the absolute hydrogen content can be understood. This allows the optical measurements to be used as stand alone techniques for measuring hydrogen content, thermodynamics and kinetics in combinatorial samples.
3:00 PM - **G3.2
High Throughput Optical Screening of Metal Hydride Systems
Jonathan Melman 1 , Darshan Kundaliya 1 , Xiongfei Shen 1 , Hyung-Chul Lee 1 , Thomas Enck 1 , Guanghui Zhu 2
1 , Intematix Corporation, Fremont, California, United States, 2 , UOP, Des Plaines, Illinois, United States
Show AbstractRecently, systems with the ability to store and release hydrogen have attracted significant interest. Many materials are known which have the ability to either absorb or release hydrogen easily; however, few are reversible under moderate conditions. Many systems appear to have favorable thermodynamic properties, but in practice have unfavorable kinetic properties. Dopants which may act as catalysts or destabilizing agents can often be added to improve the overall hydrogen storage performance. Here, we outline a method for screening potential catalysts/dopants on metal hydride materials using combinatorial synthesis and high throughput optical screening methods. The methods have been applied to measure onset temperatures of hydrogen uptake and release on both covalent and complex metal hydride systems. The method has been validated using known materials, and applied to novel systems for generation of lead dopant compositions, which were further tested in the bulk system.
3:30 PM - G3.3
Hydrogenography: Identifying the Thermodynamic Properties of Metal Hydrides in a Combinatorial Thin Film Approach.
Bernard Dam 1 , Robin Gremaud 2 , Andrea Baldi 1 , Marta Gonzalez-Silveira 1 , Yevheniy Pivak 1 , Martin Slaman 1 , Ronald Griessen 1
1 Faculty of Science, VU University, Amsterdam, Noord-Holland, Netherlands, 2 Material Science and Technology, EMPA, Duebendorf Switzerland
Show AbstractFor a sustainable society, the development of a reliable and safe energy carrier is essential. The use of hydrogen as such a carrier has many advantages. However further developments are needed to develop improved hydrogen safety sensors, separation membranes and hydrogen storage systems. While metal hydrides are ideally suited for mobile hydrogen storage applications, the use of PEM fuel cells imposes specific conditions on the desorption pressure and temperature. Experimentally, the determination of the plateau pressures of bulk samples is a very time consuming procedure. We demonstrate that the change in optical properties on the hydrogenation of metal hydrides allows for a thin film combinatorial study of the thermodynamic properties of metal hydrides [1]. Using this so-called Hydrogenography, we measure simultaneously the enthalpy of hydride formation of thousands of materials on a single thin film wafer which enables us to select the optimal composition for hydrogen storage in e.g. a ternary sample. On the basis of a simple lattice gas model we are capable to reconstruct the hydrogenation isotherms and to derive a local chemical order in for example Mg-Ti-hydrides. As a result we identify a new way to stabilize the MgH2 fcc phase and thereby enhance the kinetics of hydrogenation [2]. Our optical screening method can also be used for metallic hydrides, which do not undergo a metal-to-semiconductor transition, such as Pd [3]. In fact, using Pd as a model system, we validated our method and find that the effect of the substrate can be largely neglected after appropriate hydrogenation cycling. The extension of the hydrogenography technique to metallic hydrides allows us to also optimize the properties of hydrogen separation membranes and optical fiber hydrogen sensors.
4:15 PM - G3.4
Evaluation of IR Measurements for High-throughput Detection of Hydrogen Storage Materials.
Jason Hattrick-Simpers 1 , Lei Cao 2 , Liyang Dai-Hattrick 4 , Hiroyuki Oguchi 1 4 , Rick Paul 2 , Edwin Heilweil 3 , Robert Downing 2 , Leonid Bendersky 1
1 Materials Science Lab, National Institute of Standards and Technology, Gaithersbug, Maryland, United States, 2 NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersbug, Maryland, United States, 4 Materials Science and Engineering, University of Maryland, College Park, Maryland, United States, 3 Physics Lab, National Institute of Standards and Technology, Gaithersbug, Maryland, United States
Show AbstractThe race to discover new more promising hydrogen storage materials has led to the adaptation of combinatorial methodologies by some research groups. IR emissivity, which measures the changes in electrical resistivity due to hydrogenation, was one of the first high-throughput characterization techniques put forward to screen combinatorial samples for their hydrogen storage properties. However, very little work has gone into establishing its limitations and understanding the relationship between formation of a hydride phase and the observed change in emissivity. Here we systematically study the relationship in the Y, Mg, and Mg-Tm (transition metal) films. Absolute hydrogen content of thin-film samples is measured ex-situ via prompt gamma activation analysis. It was found that the change in IR emissivity measured is predominantly affected by the formation of hydride in the first few hundred nanometers of the sample. Additionally, studies revealed that IR emissivity can be used to distinguish between metallic phases, such as Y and YH2, and is therefore capable of detecting materials with multiple phase transformations during hydrogenation. Finally, this approach was applied to the search for elemental additives to Mg to enhance kinetics of hydrogenation. Several candidate additives have been identified using discrete combinatorial libraries that significantly increase the kinetics and will be discussed.
4:30 PM - G3.5
High-Throughput Detection of Hydrogen Sorption on Carbon-based Materials using Raman Spectroscopy.
John-David Rocha 1 , Daniel Zhao 2 , Kevin O'Neill 1 , Hong-Cai Zhou 2 , Michael Heben 3 1 , Jeffrey Blackburn 1
1 Materials and Computational Science Center, National Renewable Energy Laboratory, Golden, Colorado, United States, 2 Department of Chemistry, Texas A&M University, College Station, Texas, United States, 3 Department of Physics and Astronomy, University of Toledo, Toledo, Ohio, United States
Show AbstractA number of material systems for hydrogen storage are currently being investigated, including adsorption on carbonaceous materials and metal-organic frameworks (MOFs), metal hydrides, and chemical hydrides. In the area of hydrogen sorption, progress is often hampered by a lengthy optimization process for material systems synthesized without a priori knowledge of their potential storage capacity. In such optimization studies, the desire for combinatorial screening of large quantities of samples is often offset by the long measurement times associated with gravimetric or volumetric methods. This study addresses the issue of improved screening time for hydrogen sorption capacity via optical spectroscopy. Target samples are mounted inside a small, high-pressure cell capable of holding multiple samples at once (~ 3×3 mm2 each). The cell can be pressurized up to ~4 bar and temperature controlled between ~25 – 300 K. Samples are excited with either 488 or 532 nm laser excitation and the H2 Raman scattering modes, Q(1) and Q(0), are monitored for spectral shifts and/or broadening as a function of hydrogen pressure and sample temperature. Results of our optical screening technique for carbon-based samples such as doped single-walled carbon nanotubes or MOFs will be presented in the context of a combinatorial approach to finding starting structures or frameworks for future solid-state hydrogen storage materials.
4:45 PM - G3.6
Continuous Flow Microreactors: Rapid Process Development and Effortless Scale-up.
Martin Peacock 1
1 , AIC Technica, Alameda, California, United States
Show AbstractThe use of continuous flow microreactors is a fast serial approach to new materials’ development and is the anti-thesis of high-throughput parallel synthesis techniques. The authors have adopted lessons learnt from the failure of large high-throughput library synthesis in the pharmaceutical industry and instead adopted an approach of closed feedback serial optimization.The material scientist is able to rapidly scan the chemistry space using the microreactor technology and follow avenues that are interesting whilst avoiding experiments that are otherwise fruitless; the pharmaceutical industry discovered that most of its effort from parallel synthesis was of little interest.We demonstrate that continuous flow microreactors are an excellent platform for the rapid development of micro, nano and mesoporus materials. We use this new philosophy of fast serial to bring life to an old material in the synthesis of calcium carbonate; we demonstrate that calcium carbonate can be synthesised with an excellent control of the morphology and particle size. This control is made possible by the tight control of temperature, time, diffusional mixing and reagent/reactant stoichiometry within the microchannels. Additionally the reactors are continuous flow and therefore the conditions within the microchannel are always at steady state with the continuous removal of products and replenishment of starting materials; the problems in batch reactions with changes in concentration and the decreases in rates of reaction as a function of time are eliminated.Having developed the materials within the microreactor it is a simple matter to leave the reactors continuously running producing kilograms from 1 reactor in a 24 hour period; several systems are able to fit onto a table-top having the output equivalent to a pilot plant. These continuous flow reactors avoid the issues of scale-up associated with batch reactors as the same reactors used for lab development are then used for manufacturing. Going from the laboratory to commercialisation is accelerated as the heat and mass transport on the lab scale is identical to the large scale ensuring consistency of process and therefore product. Rather than building larger and larger reactors the philosophy is to run parallel reactor systems; scale-out rather than scale-up.
5:00 PM - G3.7
Rapid Identification of Structural Phases in Combinatorial Thin-Film Libraries using X-Ray Diffraction and Non-Negative Matrix Factorization.
Christian Long 1 , Ichiro Takeuchi 2 , David Bunker 3 , Xiang Li 3 , Vicky Karen 3
1 Physics, University of Maryland, College Park, Maryland, United States, 2 Materials Science and Engineering, University of Maryland, College Park, Maryland, United States, 3 , National Institute of Standards and Technology, Gaithersburg, Maryland, United States
Show AbstractOne of the challenges in combinatorial materials science is to find a way to quickly analyze the large quantity of data produced in a single experiment. X-Ray Diffraction (XRD) data poses a particularly difficult problem because of the detailed analysis required for every spectrum. In experiments where hundreds of compositions are fabricated in a single run, this analysis can be very time consuming. In order to speed this analysis process, we are developing techniques which can be used to analyze many spectra at once instead of the traditional one at a time approach. In this work we apply a technique called non-negative matrix factorization (NMF) to the problem of analyzing hundreds of XRD spectra from a combinatorial materials library. In comparison to k-means clustering, which sorts spectra into discrete groups, NMF has the advantage of being able to handle spectra which result from mixtures of different crystal structures. In comparison to principle component analysis, NMF has the advantage of producing basis diffraction patterns which are physically realizable. We have applied NMF for the first time to identify the unique XRD patterns present in a system and to quantify the amount of each pattern contributing to each experimental diffraction pattern. The patterns identified using NMF are then compared to reference patterns from a database of known structural patterns in order to identify known structures. By combining this structural information with composition information, it is possible to map out structural phases in composition space very rapidly and with minimal input from the materials scientist. As an example system, we look at a region of the FeGaPd ternary system.
5:15 PM - G3.8
Tools for Aggregating, Analyzing and Mining Combinatorial Data.
Wesley Jones 1 , Changwon Suh 1 , Peter Graf 1 , Korytina Daniel 2 , Craig Swank 1 , Christopher Perkins 1
1 , NREL, Golden, Colorado, United States, 2 , University of Colorado at Boulder, Boulder, Colorado, United States
Show AbstractWith the increasing volume and complexity of data produced by combinatorial experiments, and replicated characterization pipelines, understanding results is often hampered by the lack of comprehensive data management solutions, which range from initial data acquisition to final analysis and mining. Aggregating data from multiple sources as data is taken and integrating it into a framework for scientists to query is non-trivial. Analyzing data and placing that data into an integrated data set advances the capabilities of the system. Automated mining data as part of the system with the application of standard techniques such as principal component analysis enables the identification of anomalies or scientifically interesting libraries. We will discuss our system, strategy and challenges, for aggregating, analyzing and mining combinatorial data.
5:30 PM - G3.9
Advanced Segmentation Algorithms for Automatically Converting Image Data to Feature Data
Jeff Simmons 1 , Peter Chuang 2 , Landis Huffman 2 , Mary Comer 2 , Ilya Pollak 2 , Marc De Graef 3
1 Materials and Manufacturing Directorate, Air Force Research Labs, Dayton, Ohio, United States, 2 Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana, United States, 3 Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
Show AbstractBecause of the integration of scripting capabilities with microscopes, rapid generation of microstructural information in the form of images is now routinely possible with techniques such as Electron Backscatter Diffraction (EBSD), Focused Ion Beam (FIB), or automated polishing optical systems (e.g. Robo.Met-3D). In order for this information to be used in information systems, the image data must be converted to feature data, describing microstructural features such as particle sizes and morphologies, plate thicknesses, grain sizes, or other common metrics. As the image production rate of scriptable microscopes has increased, production has outstripped conventional image processing as a means of segmenting (extracting) these features from the acquired images. To this end, our group has turned to reduced human-interaction segmentation methods developed for computer vision for interpretation of arbitrary scenes, with the ultimate goal to fully automate the segmentation process. Apparently, unique to materials science, is the need to, not only segment regions accurately, but also to accurately locate the boundaries between them. This presentation gives results of two segmentation algorithms that are designed for segmenting textured regions with pixel-accuracy at the boundaries at a significantly reduced level of human interaction. The hallmark of both methods is that they can easily segment textured regions in an image without becoming confused by the intensity variations inherent in textures. The Maximization of Posterior Marginals (MPM) method is a Bayesian technique that uses a model of the image intensity, combined with a physics-based "prior" model of the material, to automatically classify pixels as belonging to a particular region. The model of the image intensity is optimized with an Expectation Maximization (EM) algorithm. Using a Simulated Annealing (SA) algorithm, the physics-based model can be adjusted to give pixel-accuracy at the boundaries. The Stabilized Inverse Diffusion Equation (SIDE) method uses a modified form of the diffusion equation that "freezes" boundaries in place, thereby achieving pixel-accuracy at the boundary from the outset, but creates many small regions because of intensity variations. The regions that differ only slightly in contrast are merged because of the "flux of intensity" across their boundaries. The EM/MPM/SA method requires a single input parameter that describes the coarseness of the textures to be segmented. The SIDE method requires a stopping condition to describe when sufficient numbers of regions have been merged. Both methods represent significant decreases in the level of human interaction to produce segmentations. Examples of segmentation of microstructures with these two techniques will be given.
G4: Poster Session
Session Chairs
Friday AM, April 17, 2009
Salon Level (Marriott)
9:00 PM - G4.10
High Throughput Search of High K and Low loss Dielectric Thin Films by Continuous Composition Spread
Ji-Won Choi 1 , Keun Jung 1 , Won-Kook Choi 2 , Nam Ki Kang 3 , Jae-Hong Choi 4 , Seok-Jin Yoon 1
1 Thin Film Materials Research Center, Korea Institute of Science and Technology, Seoul Korea (the Republic of), 2 Materials Science and Technology Research Division, Korea Institute of Science and Technology, Seoul Korea (the Republic of), 3 Electronic Materials & Packaging Research Center, KETI, Seoul Korea (the Republic of), 4 Department of Materials Science & Engineering, Korea University, Seoul Korea (the Republic of)
Show AbstractRecently, embedded passive components technology incorporates passive components into an inner layer within multilayer substrates to reduce the size of system level packaging. Capacitor materials to embed require a high dielectric constant and capacitance tolerance. Furthermore dielectric loss of thin films decides stability and performance of devices due to its leakage current. Therefore high dielectric constant and low dielectric loss thin films have to be developed.To develop dielectric compositions to meet these requirements, continuous composition spread (CCS) method was used to search optimum dielectric properties in this study. Dielectric constant of binary MgO-Ta2O5 and Ta2O5-SnO2, and MgO-SnO2 compositions were deposited by off-axis reactive co-sputtering using 2 inch target planar magnetron sputter guns arranged at 90o intervals around a three inch-diameter Pt coated substrate (Pt (130 nm)/SiO2 (300 nm)/Si wafer). MgO have low K and very low dielectric loss, and Ta2O5 and SnO2 have relatively high K and relatively low loss. Therefore, it is expected that compositions which have high K(≥20) and very low dielectric loss can be achieved from continuous composition spread of these materials. Platinum counter electrodes, which have 130 nm thickness and 3.14x10-4 cm2 area, were deposited on dielectric thin films by e-beam evaporation to form MIM capacitors for electrical characterization. The dielectric properties were measured using an automated probe station. The capacitance and loss tangent of capacitors were measured at a frequency of 100 kHz and a signal level of 500 mVrms. The composition was inferred as a function of position using Rutherford backscattering spectroscopy along with independent calibration runs.
9:00 PM - G4.11
CNT-supported PtNi Bimetallic Catalysts for Hydrogenation of Chloronitrobenzene.
Yue Liu 1 , Chuang Wang 1 , Jieshan Qiu 1
1 , Dalian University of Technology, Dalian China
Show Abstract Pt-Ni/CNTs bimetallic catalysts with different Pt/Ni atomic ratio were prepared using the wetness impregnation method, and their catalytic properties were evaluated with the selective hydrogenation of o-chloronitrobenzene (o-CNB) as a probe reaction. It has been found that the catalytic activity of Pt-Ni/CNTs decreased with the increasing of Ni loading. The Pt-Ni/CNTs catalysts with Pt/Ni atomic ratio of 3:1 exhibited the best catalytic properties with 99% selectivity of o-CAN while the conversion of o-CNB remained at 99%. The effects of reduction temperature on the performance of Pt-Ni/CNTs catalysts with Pt/Ni atomic ratio of 3:1 were studied. The results show that the catalysts reduced in hydrogen at 600 oC exhibited excellent catalytic property for the selective hydrogenation of o-CNB.
9:00 PM - G4.12
High Throughput Search of Al and Ga doped ZnO Thin Films
Ji-Won Choi 1 , Keun Jung 1 , Won-Kook Choi 2 , Jong-Han Song 3 , Wan-Keun Bang 4 , Seok-Jin Yoon 1
1 Thin Film Materials Research Center, Korea Institute of Science and Technology, Seoul Korea (the Republic of), 2 Materials Science and Technology Research Division, Korea Institute of Science and Technology, Seoul Korea (the Republic of), 3 Advanced Analysis Center, Korea Institute of Science and Technology, Seoul Korea (the Republic of), 4 Research Center, Samwon Vacuum Co., Ltd., Gyeonggi-do Korea (the Republic of)
Show AbstractTransparent conducting oxides (TCO) are widely used in a large field such as flat panel displays, touch panel displays, thin film transistors, solar cells, heaters, defrosters, and optical coatings. Transmittance and electrical conductivity are typically trade-off in metal, however transparent conducting oxides can have both visual transparency and electrical conductivity. Tin doped indium oxide (ITO) has been used as a TCO material due to it’s low available resistivity (1-2×10-4 Ω cm) and high transparency in the visible range. However, 45 % of indium in the world market is consuming as a TCO materials of flat panel display and rapid emerge of InP as semiconductors and opto-electronic materials is steeply raising the indium price. Above all things, indium deposits will be exhausted in the near future. Therefore indium free TCO materials, which have low resistivity and high transmittance have to be developed. ZnO based materials are good candidates as TCOs because ZnO has good transmittance (≥80 %) in the visible range and low resistivity (~ 10-4 Ω cm) depending on deposition conditions.To develop TCO compositions to meet these requirements, continuous composition spread (CCS) method was used to search new compositions, which have optimum electrical and optical properties. Ternary Al2O3-Ga2O3-ZnO compositions were deposited by off-axis reactive co-sputtering using 4 inch target planar magnetron sputter guns arranged at 90o intervals around a six inch-diameter alkali free glass substrate. The electrical properties of 6 inch wafer scale specimens were measured using an automated probe station interfaced with four point probe and the optical properties were measured using an UV-visible spectrophotometer. The composition was inferred as a function of position using Rutherford backscattering spectroscopy along with independent calibration runs.
9:00 PM - G4.13
Evaluation of the Effect of Inhibitors on Conventional and Controlled Free Radical Polymerizations using a High throughput Approach.
Mohammed Nasrullah 1 , Dean Webster 2 , Vishal Sonalkar 1 , Thanusha Koralage 1
1 Center for Nanoscale Science and Engineering, NORTH DAKOTA STATE UNIVERSITY, Fargo, North Dakota, United States, 2 Department of Coatings and Polymeric Materials, North Dakota State University, Fargo, North Dakota, United States
Show AbstractThe evaluation of the effect of inhibitors for conventional free radical polymerization and atom transfer radical polymerization (ATRP) using a high throughput approach is discussed. Synthetic polymers are obtained largely by two different well established methods namely step- and chain-growth polymerization. In free radical chain-growth polymerization, the double bonds of vinylic monomer are polymerized in a chain reaction using a suitable free radical initiator. Vinylic monomers are very prone to polymerization; hence parts per million (PPM) amounts of inhibitors are added to increase the shelf life of the monomers. Commercial manufacturers of styrenic/acrylate polymers usually do not remove the inhibitors before conducting free radical polymerizations. Hence this proposes additional experiments to explore the effect of inhibitors on molecular weight of polymers. The main focus of this work is 1) to examine the effects of inhibitors viz. MEHQ and TBC for the free-radical polymerization of n-butyl methacrylate and n-butyl acrylate both with and without inhibitor and 2) to determine the effect on ATRP of styrene, t-butyl acrylate, n-butyl acrylate and n-butyl methacrylate when polymerized with and without the removal of the inhibitor. All the polymerizations were carried out using a combinatorial/high throughput approach where design of experiments (DOE) was used to create libraries of polymerization reactions to efficiently explore the effects of the inhibitor. All of the polymers synthesized were characterized using high throughput rapid gel permeation chromatography. Excellent conversion and PDI were obtained within the given reaction conditions for both monomer as-received and purified monomer using ATRP. The presentation will discuss how the study was done and the effect of inhibitor on the monomers studied using free radical and atom transfer radical polymerizations by high throughput approaches.
9:00 PM - G4.14
Gold Nanoparticle Liquids as Surface Lubricants in MEMS Switch Contacts.
Michael Jespersen 1 2 , Steven Patton 3 , Peter Mirau 1 , Robert MacCuspie 1 2 , Andrea Elsen 1 , John Kelley 1 , Richard Vaia 1 , Andrey Voevodin 4
1 Nanostructured and Biological Materials Branch, Air Force Research Laboratories, Wright-Patterson AFB, Ohio, United States, 2 Research Associateship Programs, National Research Council, Washington, District of Columbia, United States, 3 University of Dayton Research Institute, University of Dayton, Dayton, Ohio, United States, 4 Thermal Materials Branch, Air Force Research Laboratories, Wright-Patterson AFB, Ohio, United States
Show AbstractMicroelectromechanical systems (MEMS) switches have a broad range of applications in a number of important industries, including the aerospace, communications, and electronics sectors. However, contact failure, especially during hot switching, is one of the primary obstacles to widespread commercialization of next generation MEMS devices. Even though reliability remains a critical issue, few studies have investigated the use of surface lubricants to address the fundamental failure mechanisms in MEMS contact switches. One published study used self-assembled monolayers (SAMs) as a switch lubricant, but these SAMs thermally decompose in the contact, resulting in premature failure.[1] We also have investigated bimetallic nanoparticles deposited onto MEMS contacts as nanomaterial-based lubricants, which improved the performance and durability of MEMS switches by orders of magnitude in terms of number of contact cycles until failure.[2] In recent studies, we have studied gold nanoparticle liquids as conductive surface coatings in MEMS switch contacts.[3] Nanoparticle liquids (NPLs) are monolithic hybrid materials consisting of an inorganic core stabilized by a covalently-bound ionic liquid corona, which imparts liquid-like properties to the overall nanostructure. Performance of NPL-lubricated contact surfaces were investigated, using a micro/nanoadhesion apparatus as a MEMS switch simulator with in-situ monitoring of contact resistance and adhesion force. Ex-situ analyses of the chemical and physical processes at the contact interfaces were carried out using SEM, TEM, XPS, and scanning Auger spectroscopy. When applied to MEMS switch contacts, gold NPLs form a large number of conductive nanoscale contact asperities that result in size-restricted melting regions. Gold NPL surface coatings have been shown to significantly increase the durability and reliability of MEMS switch contacts in hot-switching cyclic contact experiments by limiting nanowire growth that leads to shorting failure. We have also studied the molecular dynamics of the ionic liquid corona in these materials by NMR spectroscopy in order to understand their liquid-like behavior. The liquid properties of NPLs impart self-healing properties to these reconfigurable surface coatings. [1] Patton, S. T.; Eapen, K. C.; Zabinski, J. S.; Sanders, J. H.; Voevodin, A. A. “Lubrication of MEMS RF switch contacts using self-assembled monolayers.” J. Appl. Phys. 2007, 102, 024903.[2] S. T. Patton, et al. “Bimetallic Nanoparticles for Surface Modification andLubrication of MEMS Switch Contacts.” Nanotechnology 2008, 19, 405705.[3] A. A. Voevodin, et al."Nanoparticle-Wetted Surfaces for Relays and Energy Transmission Contacts." Small 2007, 3, 1957-1963.
9:00 PM - G4.15
Synthesis and Characterization of ZnCdSe Powders for Phosphor Application
Vello Valdna 1 , Maarja Grossberg 2 , Jaan Hiie 3 , Yacouba Diawara 4 , Roger Durst 5 , Hisham Menkara 6
1 Dept. of Materials Science, Tallinn Univ. of Technology, Tallinn Estonia, 2 , Tallinn Univ. of Technology, Tallinn Estonia, 3 , Tallinn Univ. of Technology, Tallinn Estonia, 4 , Bruker AXS, Inc., Madison, Wisconsin, United States, 5 , Bruker AXS, Inc., Madison, Wisconsin, United States, 6 , PhosphorTech Corporation, Lithia Springs, Georgia, United States
Show AbstractCopper and chlorine doped group II-VI compound ZnSe and ZnSe-based solid solutions are known as efficient luminescence materials for displays, scintillator screens, lasers and detectors. (ZnCd)Se alloy allows to shift a photoluminescence peak from orange to near infrared, depending on the alloy composition. (ZnCd)Se alloy exhibits the lowest afterglow of any commercial X-ray phosphor and has the highest known theoretical conversion efficiency of 32%. II-VI alloys can be readily recrystallized and doped at temperatures below 1000 C if a halogen flux is used whereas wide bandgap oxides, nitrides and carbides need a much higher fabrication temperature. In this study we present the properties of the different (ZnCd)Se alloys. Synthesized in 2-zone tube furnace phosphor powders have a particle size of 5-10 microns, best suitable for the X-ray conversion screens of CCD cameras. Fabricated crystals have high quality and brightness, and exhibit a good stability under UV or X-ray radiation. Compared to oxide-based phosphors, (ZnCd)Se-based phosphors have about order of magnitude lower afterglow that allows the shorter readout time of cameras. ZnSe has a spectral peak at 1.92 eV (647 nm). 5 mol% of CdSe in (ZnCd)Se alloy shifts peak to 1.84 eV (675 nm), and 50 mol% CdSe to 1.34 eV (927 nm).
9:00 PM - G4.16
PLD Combinatorial Growth of Doped (Ba,Sr)TiO3 Thin Films Libraries : Structural, Dielectric and Raman Spectroscopy Investigations.
Jerome Wolfman 1 , Houssny Bouyanfif 2 , Antoine Ruyter 1 , Kesava Yellareddy 1 , Guozhen Liu 1 , Jie Qiu 1 , Joe Sakai 1 , Cecile Autret 1 , Monique Gervais 1 , M. El Marssi 2 , Y. Yuzyuk 3
1 Laboratoire LEMA UMR CNRS CEA 6157, Université François Rabelais, Tours France, 2 Laboratoire LPMC, Université de Picardie Jules Verne, Amiens France, 3 Institute of Physics, Rostov State University, Rostov-on-Don Russian Federation
Show AbstractBulk compounds from the BaxSr1-xTi1-yAyO3 (BST doped with A = Mg, Zr…) solid solution are promising candidates for microwave applications relying on their voltage tunable high dielectric permittivity. However BST films show lower performances than their bulk counterpart. The decrease of the dielectric and tunability properties is usually ascribed to the film microstructure and growth induced defects. A clear understanding of the defects impact and the structure-properties relationship is needed to optimize dielectric performances. In this work we grew BST and BST-doped composition spread thin films libraries by combinatorial pulsed laser deposition. The thin films were characterized by RHEED, X-ray diffraction, TEM, EDX, near field microscopy and Raman spectroscopy. Finally electrical properties of capacitors were studied. We probed and optimized the composition gradient over a 10*10 mm2 area using X-ray micro-diffraction, EDX and TEM. The X-rays and dielectric measurements show a clear trend from a STO-like to BTO-like response across the un-doped libraries. Correlations between composition, microstructure, dielectric and ferroelectric properties are evidenced. In particular a critical Ba concentration inducing elastic relaxations is shown to reduce the dielectric performances. Similar correlations will be shown with Zr-doped libraries. In parallel observation of underdamped soft mode suggests stress-induced artificially ordering of Ti ions for high content of Ba. Such a result opens the way to use stress engineering for controlling order-disorder interplay in the (Ba,Sr)TiO3 system.
9:00 PM - G4.2
Use of the Source of ``Soluble” Magnesium Mg(anthracene).3THF and Rieke Zinc, Magnesium, Nickel, and Copper for Preparation of New ``inorganic” Grignard Reagents and Metal Phthalocyanines.
Rubi Hernandez Carrillo 1 , Betsabee Olvera Perez 1 , Boris Kharisov 1 , Oxana Kharissova 1 , Ubaldo Ortiz Mendez 1 , Juan Jacobo Ruiz Valdez 1
1 Facultad de Ciencias Quimicas, CIIDIT-Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon, Mexico
Show Abstract“Inorganic” Grignard reagents are known starting from the middle of 90th and currently this is not a well-developed research area. In this work, activated Rieke metals (Zn, Mg, Ni, Cu) and a classic source of a “soluble” magnesium Mg(anthracene).3THF were applied as precursors for reduction of a series of anhydrous metal salts in THF medium to produce new “inorganic” Grignard reagents in mild conditions. These syntheses were carried out by the following main routes: 1) interaction of recently prepared Rieke metals with anhydrous magnesium halides, 2) interaction of Rieke magnesium with anhydrous metal (Zn, Mg, Ni, Cu, etc.) halides, and 3) interaction of Mg(anthracene).3THF with anhydrous metal halides. The used Rieke metals have shown good reactivity in these processes. A series of obtained products are currently being studied as precursors for obtaining new nanoalloys and intermetallic compounds. Additionally, the unstable complex Mg(anthracene).3THF showed good properties as precursor for obtaining magnesium phthalocyanine at low temperature (5-23oC) from phthalonitrile in a series of non-aqueous solvents with moderated yields.
9:00 PM - G4.3
Structural characteristics of carbon nano-dots fabricated by the Thermo-electrical Pulse Induced Evaporation.
Hye Yun Park 1 , Hyun Wook Kim 1 , Krishna Kumar 1 , Si Kyung Choi 1
1 Material science and engineering, Korea Advanced Institute of Science and Technology, Deajeon Korea (the Republic of)
Show AbstractCarbon based materials, carbon nano-dot, tube and graphene have been attracted tremendous attention from both the experimental and theoretical scientific communities in recent years. One of them, carbon quantum dots are zero dimensional structures having a size of about 100 Å and a nano-scale semiconductor structure. Notably, carbon nano-dots are non-toxic and has photoluminescence effect which can be applicable to biology. Carbon nano-dots have been fabricated from laser ablations(1) and CVD method(2), but it is very diffcult to control the dots size by these methods. It is a challenge to establish a new processing method or fabrication method for a well-controlled size distribution of nanodots. Recently, we have developed a novel method, i.e.,Thermo-electrical Pulse Induced Evaporation (TPIE) of synthesizing a various kind of nanostructures. The thermal energy and electrical pulse are simultaneously introduced into a source material at a high vacuum condition and then source materials are evaporated. The escaping atoms from a source material transfer to a substrate and grow into the nanostructure of a source material. The growth mode (dot, rod/wire, and tube) of nanostructures can be easily controlled by varying the applied temperature and electrical pulse strength. Notably, the thermal energy and electrical energy applied to evaporate carbon atoms in the TPIE method are required less than the respective evaporating energies applied individually. In this presentation, we will report the structural cheracteristics of carbon nano-dots fabricated by TPIE methodCarbon nano-dots were directly fabricated on the doped Si (111) crystal surface for measuring electrical properties of the dots. For fabricating carbon nano-dots, 500 degrees and 10 voltage pulse were typically introduced into the graphite source material. The formation of the dots was confirmed using atomic force microscope (AFM) and scanning electron microscope (SEM). The electrical properties and shape of dots were evaluated from scanning tunneling microscope (STM) observations. After sonicating Si substrate in alcohol solution, the dots were dispersed on the amorphous carbon coated Cu grid for high resolution transmission electron microscope (HRTEM). The dots after sonicating were treated in the Polyethylene Glycol solvent for observing photoluminescence effect. Our results clearly showed that the defect free carbon nono-dots with several nm dimeters and several unit cell heights could be fabricated by TPIE methods, and also have the photoluminescence effect. It is expected that the size distribution of carbon nano-dot can be contolled as functions of TPIE parameters.Reference1. Ya-Ping Sun et al., J. Am. Chem. Soc. 128, 7756-7757(2006)2. A. C. Ferrari et al., Phys. Rev. Lett. 97, 187401, (2006)
9:00 PM - G4.4
A Simple Combinatorial Method Accelerating R&D of Synthesis and Application of Single-walled Carbon Nanotubes.
Suguru Noda 1 , Kei Hasegawa 1 , Hisashi Sugime 1 , Yosuke Shiratori 1
1 Department of Chemical System Engineering, The University of Tokyo, Tokyo Japan
Show AbstractCarbon nanotubes (CNTs), especially single-walled CNTs (SWCNTs), have been attracting much attention owing to their unique one-dimensional structure and excellent properties. Many applications have been proposed and extensively studied, however, the difficulties in their synthesis and implementation are limiting their practical applications. Catalytic growth of SWCNTs on substrates by chemical vapor deposition (CVD) is promising for direct fabrication of SWCNT devices. Catalyst nanoparticles have crucial roles in controlling their diameter, density, and length. We have developed a "combinatorial masked deposition (CMD)" method [1] enabling simple fabrication of catalyst libraries. Gradient thickness profiles of catalyst metals are formed on substrates by sputtering through a physical filter, annealed at CVD temperatures, and then transformed into catalyst particles of a series of sizes and compositions. By using this CMD method, we have been studying SWCNT growth process and developing SWCNT devices. An example is the reproduction of the water-assisted CVD method [2] realizing millimeter-thick SWCNT forests in a reaction time of several minutes from an ethylene feedstock and an Fe/Al2O3 catalyst. CMD libraries enabled us to reproduce such SWCNT growth and clearly showed that the window of CVD condition is quite narrow and that the Al2O3 underlayer catalytically enhanced the SWCNT growth rate [3]. Real-time monitoring of growing SWCNTs on a CMD library now enable us to determine activity and lifetime of a series of catalyst in a single CVD run. By using this CMD method, binary catalyst can also be studied systematically on a single substrate. Co-Mo catalyst is known effective to grow SWCNTs from an ethanol feedstock [4]. A CMD library clearly showed the existence of "multiple optimums" in catalyst composition and thickness for such growth [5]. 200 catalyst conditions can now be evaluated in one day from library preparation, SWCNT growth, to evaluation of SWCNT diameters by automated mapping of Raman scattering spectra. A CMD library yields a large variety of CNTs on a single substrate, from SWCNTs to multi-walled CNTs in morphologies from individuals, grasses, spikes to forests. This substrate becomes a library of electron field emitters. A single luminescence test clearly shows suitable conditions for CNT structures/morphologies as well as catalyst conditions [6]. Rapid SWCNT growth in a self-organized morphology now enables instant mounting of SWCNT device elements. Our simple combinatorial method, CMD, surely accelerates R&D of SWCNTs in both basics and applications. [1] S. Noda, et al., Appl. Surf. Sci. 255, 372 (2004).[2] K. Hata, et al., Science 306, 1362 (2004).[3] S. Noda, et al., Jpn. J. Appl. Phys. 46, L399 (2007).[4] Y. Murakami, et al., Chem. Phys. Lett. 385, 298 (2004).[5] H. Sugime, et al., Carbon, in press. [6] Y. Shiratori, et al., J. Phys. Chem. C, in press.
9:00 PM - G4.5
In situ Multi-beam Optical Stress Sensor (MOSS) Measurement for Low Stress Deposition.
Anahita Afshin Navid 1 , Andrew Detor 2 , Eric Chason 3 , Andrea Hodge 1
1 Aerospace and Mechanical engineering, University of Southern California, Los Angeles, California, United States, 2 Nanoscale Synthesis and Characterization Laboratory, Lawrence Livermore National Laboratory, Livermore, California, United States, 3 Division of Engineering, Brown University, Providence, Rhode Island, United States
Show AbstractPhysical vapor deposition techniques provide a wide range of materials processing. However, residual stresses typically limit the applications or coating thickness. The purpose of this study is evaluating the instantaneous stress during deposition using an in-situ Multi-beam Optical Stress Sensor method. This allows us to change coating parameters to reduce residual stress during deposition. An analysis between low and high residual stress materials (copper and tantalum) is presented as a function of coating time. The significant changes in the in-situ stress states as a function of time as well as a large deviation from the ex-situ stress measurement is observed. The MOSS technique provides important information regarding the stress evolution as a function of deposition condition and the overall coating thickness, thus providing a novel method to produce low stress coatings.
9:00 PM - G4.6
An Automated Instrument for High-throughput Screening of Polymer Toughness.
Chavanin Siripirom 1 2 , James Bahr 2 , Dean Webster 1 2
1 Department of Coatings and Polymeric Materials, North Dakota State University, Fargo, North Dakota, United States, 2 Center for Nanoscale Science and Engineering, North Dakota State University, Fargo, North Dakota, United States
Show AbstractAn automated, high-throughput instrument for high-throughput screening of polymer toughness was developed. The test is in the form of circular free-film indentation that deforms the film until rupture. One main focus of our combinatorial research laboratory is in the development of organic coating for airplanes and ships. Toughness and elastic modulus are important parameters in their design. The current methods are conventional tensile and tearing tests. These tests require a significant amount of time in specimen preparation (die cutting) and testing time, including significant manual handling of test specimens. Thus, this high-throughput instrument is being implemented in the workflow in order to allow us to rank toughness and elasticity. Toughness of a material can be defined with various methods such as fracture toughness with known crack size and energy-to-break in a dumbbell shaped specimen. Circular free-film puncturing can be easily automated. A specially designed 8 × 4 in. template is used to obtain free films. Finite element analysis and numerical analysis of the shell problem are used to aid in understanding the test parameters and also in estimating the elastic modulus. Experiments are carried out to validate the use of the instrument with silicone elastomer and polyurethane libraries. Tear and tensile experiments are used for correlations. The high-throughput system shows good ranking capability to that of the conventional tests.
9:00 PM - G4.7
Synthesis by Prato Reaction and in situ UV-characterization of Several Fulleropyrrolidine Derivatives.
Marco Aurelio Jimenez Gomez 1 , Mauricio Garza Castanon 2 , Oxana Kharissova 1 , Ubaldo Ortiz Mendez 1
1 , CIIDIT-Autonomous University of Nuevo Leon, Monterrey Mexico, 2 , Corporación Mexicana de Investigación en Materiales S.A. de C.V., Saltillo, Coahuila, Mexico
Show Abstract1-methyl-2-phenylfulleropyrrolidine (1), 1-methyl-2-(4-(1-piperidyl)-phenyl)-fulleropyrrolidine (2), 1-methyl-2-(4-fluorophenyl)-fulleropyrrolidine (3) and 1-methyl-2-(3-hydroxy-2-naphtyl)-3,4-fulleropyrrolidine (4) were synthesized by Prato reaction and characterized in situ in the reaction mixture by UV-vis spectroscopy, high performance liquid chromatography (HPLC) and matrix assisted laser desorption ionization (MALDI). Compounds 1 and 2 were isolated as individual substances, in a difference of the compounds 3 and 4, so the eluents used for separation of 3 and 4 were not sufficiently powerful for complete separation of product and unreacted C60. Compounds 1, 2, and 3 were synthesized in good yields. A comparison of theoretical and experimental UV spectra was carried out. Computational results for compounds 1 and 4 are almost identical that experimental respect the wavelength of absorption in UV spectra, this means that kinetic interactions between ions in these compounds are not very important. Computational results for compounds 2 and 3 show a little shift in wavelength respect the experimental results, that means that kinetic interactions between ions in these compounds are more relevant that for compounds 1 and 4, however kinetic interactions of ions are still weak because the shifts in wavelength are around 1.45%.
9:00 PM - G4.8
Fouling-release Performance of Siloxane-polyurethane Coatings Using Combinatorial High-throughput Methods.
Rajan Bodkhe 1 , Dean Webster 1 , Maureen Callow 2 , Stephanie Thompson 2
1 Department of coatings and Polymeric Materials and Center for Nanoscience Scale Science and Engineering, North Dakota State University, Fargo, North Dakota, United States, 2 School of Biosciences, University of Birmingham, Birmingham United Kingdom
Show AbstractIn this study, the effect of PDMS molecular weight and content on the fouling-release performance of siloxane-polyurethane coatings was explored. Biological fouling of ships by marine organisms results in reduction of ship speed and maneuverability and has serious consequences on mission performance and fuel consumption. Fouling-release coatings permit easy removal of marine organisms on the ship’s hull via the application of a shear force to the surface. Polydimethylsiloxane (PDMS) surfaces are quite efficient in deterring the adhesion of most marine organisms due to its low surface energy and low modulus. Combinatorial High Throughput Experimentation (CHTE) was used to synthesize and formulate libraries of siloxane-acrylic-polyurethane coatings. The resulting coatings were tested for their physical, mechanical and performance properties. The coating formulations included 3-aminopropyl-terminated polydimethylsiloxane (APT-PDMS), a polyisocyanate crosslinker, acrylic polyol and non-toxic curing catalyst. Siloxane-polyurethane coatings were made having a range of siloxane content and a molecular weight range of 2500-30000 g/mole. Two different isocyanate crosslinkers were also studied. The resulting coatings were studied for water stability by comparing their surface energy and pseudo-barnacle adhesion both before and after ageing the coatings in water for 30 days. The coatings were found to be stable upon water immersion. It was observed that even at very low percent loading of PDMS, the coatings were hydrophobic.The fouling release performance of the coatings was tested towards Ulva sporelings and Navicula incerta. The performance of most of the coatings was found to be better compared to the silicone standard. No Ulva removal was observed from coatings containing 0% siloxane which confirms that siloxane on the surface is necessary for the removal of Ulva sporelings. The Ulva release increased with an increase in the molecular weight and percent siloxane for coatings crosslinked with HDT 90. On the other hand the diatom release decreased with an increase in the molecular weight of the PDMS.
9:00 PM - G4.9
Synthesis and Luminescence of Deep Blue-emitting Phosphorescent Iridium (III) Complex in Ultrasound Reaction
Hong Jeong Yu 1 , Kwanhwi Park 1 , Wonkeun Chung 1 , Sung Hyun Kim 1
1 Dept. of Chemical and Biological Engineering, Korea University, Seoul Korea (the Republic of)
Show AbstractIr(pmb)3 (Iridium (III) Tri(1-phenyl-3-methylbenzimidazolin-2-ylidene-C,C2’) was synthesized for the deep blue-emitting phosphorescent Iridium (III) complex. The first reaction step is the synthesis of Ir-dimer ([(pmb)2IrCl]2) with IrCl3 3H2O and [pmb]I-, and the second reaction step is the synthesis of Ir(pmb)3 with Ir-dimer and [pmb]I-. The reaction yield of Ir-dimer is known as very poor (12.7%). In this work the yield of Ir-dimer was increased with higher intensity of ultrasound. The maximum yield of Ir-dimer was 52.8 % at 450 W/m2 of ultrasound intensity. Ir(pmb)3 could be synthesized only in one step at over 180 C in 20 bar. The reaction yield was increased 20% by injecting ultrasound during the reaction and two-step-reaction was shorten to one-step-reaction by high reaction temperature in high pressure.Organic light emitting devices were fabricated with the synthesized Ir(pmb)3. The devices consisted of a 30-nm-thick 4-4-bis N-1-naphthyl-N-phenyl-aminobiphenyl (NPD) as hole transport layer and a 10-nm-thick 4,4,4-tris carbazol-9-yl-triphenylamine (TCTA) as electron blocking layer. The 25-nm-thick EML consists of either fac or mer- Ir(pmb)3, co-deposited with UGH2 or CBP or mCP. Finally, a 35-nm-thick electron transporting 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) was deposited. Cathodes consisting of a 0.8-nm-thick layer of LiF and a 120-nm-thick layer of Al were patterned. The devices which were prepared with the meridianal isomer of Ir(pmb)3 give higher EP efficiencies than those with the facial isomer. Host materials of large bandgap were tested for deep blue emitting device. UGH2 was used but the device performance is very poor. CBP and mCP were also used to obtain deep blue emitting devices. We obtained sky blue emitting device because the bandgap of CBP is smaller than that of Ir(pmb)3. mCDP which has similar bandgap to Ir(pmb)3 showed both deep blue emitting and reasonable device performance among those host materials.