Symposium Organizers
David L. Adler DLA Instruments Corporation
Ernst Bauer Arizona State University
Gary L. Kellogg Sandia National Laboratories
Andreas Scholl Lawrence Berkeley National Laboratory
Symposium Support
Elmitec Elektronenmikroskopie GmbH
IBM T.J. Watson Research Center
Sandia National Laboratories
SPECS GmbH
W1: Organic Films / Biological Materials
Session Chairs
Robert Nemanich
Ruud Tromp
Monday PM, March 24, 2008
Room 3011 (Moscone West)
3:00 PM - **W1.1
Organic Films on Semiconductors Studied with LEEM/PEEM.
Rudolf Tromp 1
1 , IBM T.J. Watson Research Center, Yorktown Heights, New York, United States
Show AbstractOrganic thin films are notoriously difficult to study with electron microscopy techniques because of their extreme sensitivity to radiation induced damage by the incident electron beam. Low Energy Electron Microscopy (LEEM), utilizing electron energies of just a few eV, as well as Photo Electron Emission Microscopy (PEEM) operate in a regime where radiation damage is much less of a concern. We have applied these techniques to the growth of organic thin films on semiconductor surfaces in an effort to clarify and elucidate some of the key processes that determine the crystal structure and morphology of such films, on insulating, semiconducting, and metallic substrates, both amorphous and crystalline. In this talk I will give an overview of recent results, and discuss opportunities for future research.
3:30 PM - W1.2
Giant Grain Formation Induced by Molecular Anisotropy in Pentacene Film Growth.
Jerzy Sadowski 1 , Abdullah Al-Mahboob 1 , Yasunori Fujikawa 1 , Rudolf Tromp 2 , Toshio Sakurai 1
1 Institute for Materials Research, Tohoku University, Sendai Japan, 2 , IBM T.J. Watson Research Center, Yorktown Heights, New York, United States
Show Abstract Pentacene (Pn – C22H14) is attracting a great interest as it has been already successfully used in the organic field-effect transistors, having field-effect mobilities surpassing that of amorphous silicon devices. Pentacene films are a promising material for the practical realization of cheap and versatile organic-based devices. However, a major challenge remains – we need a better understanding of the growth of organic materials as thin films in order to utilize them in high-performance organic electronics. To do so we have to realize that organic materials are highly anisotropic, often in both, crystal and molecular structures, which complicates their growth mechanisms, often resulting in pronounced anisotropy in electronic properties of organic-based devices. Low-energy electron microscope (LEEM) is an excellent tool for the in-situ investigations of the organic films growth. It provides a real-time capability for the analysis of the growth processes, ensuring at the same time a minimum damage to the highly sensitive organic films. In our LEEM study of the pentacene growth on bismuth (Bi) surfaces we have observed a formation of the "standing-up", epitaxial Pn domains, with diameters in the order of ~0.2 mm. We propose that the molecular anisotropy and related to it, variant molecule-substrate interactions, can critically affect the nucleation process of the "standing-up" epitaxial Pn film, resulting in the low nucleation density and thus the huge domain size. Analyzing the delay between shutting off the Pn flux and the actual end of the growth (step progression in the Pn monolayer) we have found that at room temperature the Pn molecules are mobile on the surface before being incorporated into an ordered monolayer for as long as ~10 s. This very long relaxation time implies a relatively strong interaction between Bi surface and the Pn molecules in their diffusive state, leading to a large critical density of diffusing molecules required for the nucleation event to occur. The above observation can be explained by a simple, yet plausible assumption that the Pn molecules are diffusing in a "flat" configuration and they have to overcome a certain energy barrier to "stand-up", forming a critical nucleus that can evolve into the energetically stable film. Thus the film growth is governed by the balance between the interfacial energies (related to the molecular anisotropy) and the total energy of the crystallized film. The above described phenomenon is an important indication that the molecular anisotropy can play a significant, often underestimated role in the crystallization of organic thin films, and thus it can strongly influence the performance of the thin film-based devices.
3:45 PM - W1.3
Kinetics-Driven Polycrystallization in Anisotropic Growth of Pentacene Thin Film.
Yasunori Fujikawa 1 , J. Sadowski 1 , G. Sazaki 1 , S. Nishikata 1 , A. Al-Mahboob 1 , K. Nakajima 1 , R. Tromp 2 , T. Sakurai 1
1 Institute for Materials Research, Tohoku University, Sendai Japan, 2 , IBM, T.J. Watson Research Center, Yorktown Heights, New York, United States
Show AbstractUnderstanding thin film growth of organic materials towards its quality control has been a challenging issue because of additional degrees of freedom originating from the anisotropy in their molecular and crystal structures. We used low energy electron microscopy, with a wide dynamic range in field of view covering sub-mm to nm as well as micro-diffraction capability, to investigate the crystal axis alignment in the growth of pentacene (Pn) films, revealing that textured structure can evolve from a single nucleus following a general rule coming from anisotropic growth speed of Pn with kinetic growth condition. Pn island growth exhibits a three-fold symmetry on hydrogen-terminated Si(111), having preferential growth orientations. Applying tilted-beam imaging mode, three distinctively different contrasts are observed within the individual dendritic branches of the fractal Pn islands. The distribution of these different contrasts follows a general rule to form each individual branch with three differently contrasted stripes along the branch direction, where the new branching occurs from the side stripe of the existing branch to make it as the center stripe of the new branch. Each individual contrast observed in the LEEM image can be assigned to the specific type of the three micro-beam low-energy electron diffraction (µ-LEED) patterns, corresponding to the Pn epitaxial domains where their b-axes (longer in-plane unit vectors) closely align along each of three {1-10} directions of the Si(111) substrate. These observations suggest that the Pn grains are polycrystalline even though they develop from the single nucleus, which is induced by a regular driving force rather than possible randomness on the substrate. Such polycrystallization is observed also on different Si(111) surfaces terminated by Bi thin film as well as Bi-root 3 reconstructed surface, which strongly implies that it is independent from specific interfacial energetics.Growth speed anisotropy of Pn single crystal domain observed as its preferential growth towards the b-axis gives a reasonable explanation for this self-polycrystallization with the kinetic growth mechanism in the DLA-type growth. In this kind of growth, a positive feedback is applied to the growth speed by the step advance towards the density gradient of diffusing molecules, which determines branching direction. The growth of rotated domains at the side of the branch with preferential growth directions (b-axes) pointing towards the branching direction also becomes more dominant after the nucleation due to this positive feedback, despite their energy disadvantage at their nucleation stage. The polycrystallization mechanism revealed in our study implies the possibility of orientation control of Pn domain by the control of the diffusion direction, which is realized on self-1D-patterned Bi film on Si(111) surface.
4:30 PM - **W1.4
Variable Wavelength UV-PEEM Imaging of Biomolecules and Cell Organelles.
Xianhua Kong 1 , Jacob Garguilo 1 , Glenn Edwards 2 , John Simon 3 , Robert Nemanich 4
1 Physics, NC State University, Raleigh, North Carolina, United States, 2 Physics, Duke University, Durham, North Carolina, United States, 3 Chemistry, Duke University, Durham, North Carolina, United States, 4 Physics, Arizona State University, Tempe, Arizona, United States
Show AbstractThe measurement of the photothreshold or photoionization of adsorbed biomolecules and cell organelles can significantly contribute to understanding of the molecular bonding mechanisms and to understanding the development of oxidative stress in photosensitive organelles. In this research variable wavelength photo electron emission microscopy (PEEM) with tunable UV light from the Duke University free electron laser is applied to image single DNA and fibrinogen molecules adsorbed onto silicon surfaces and to image melanin containing organelles (melanosomes). High resolution images (~10nm) were obtained with FEL photon energies from 4 to 6 eV. Wavelength dependent image sequences were analyzed to determine the photothreshold of individual molecules or melonosomes. The relationship between the photoionization threshold and the electrochemical potential referenced to the normal hydrogen electrode is used to quantify the surface oxidation potential of the melanosomes. The results indicate different photothresholds depending on the relative eumelanin and pheomelanin content and microstructure. In the single molecule measurements, DNA or human plasma fibrinogen were adsorbed onto cleaned and passivated silicon surfaces. Depending on the surface preparation, the PEEM images displayed different relative contrast between the biomolecules and the substrates, which was explained in terms of charge transfer and the relative photothreshold of the substrate and adsorbed molecule.
5:00 PM - W1.5
LEEM Investigation of Chiral Growth of 6,13-pentacenequinone Films.
Abdullah Al-Mahboob 1 , Jerzy Sadowski 1 , Yasunori Fujikawa 1 , Toshio Sakurai 1
1 , Institute for Materials Research, Tohoku University, Sendai, Miyagi, Japan
Show AbstractDespite a recent interest in application of organics to electronic industry several aspects regarding organic film growth are still needed to be solved before full materialization of organic-based devices. An anisotropy in molecular and crystal structures often complicates the growth processes. This is especially important in thin film fabrication where crystalline symmetry of the film is further lowered by the presence of the interface. Pentacene (C22H14, Pn) and its derivatives are important ingredients for the organic electronic devices. 6,13-pentaceneqauinone (C22H12O2, PnQ) is an oxidation product of Pn and commonly present as impurity in Pn. PnQ has a bilayer crystal structure with molecules having relatively large tilt at surface plane and herringbone arrangements at alternate layers. A p-type electronic transport and a yellow luminescence in PnQ thin-film has been demonstrated recently [1]. In this work, we studied PnQ to understand the effect of molecular packing anisotropy on film growth.Thin film growth of PnQ was studied by low energy electron microscopy (LEEM) and complementary ab-initio density functional theory (DFT) calculations [2]. At the initial stage of PnQ growth on Si(111), non-crystalline, compact islands or clusters (type-I) were observed to nucleate on a disordered wetting layer. Elongated, crystalline islands (type-II) nucleated subsequently at the type-I islands. A subsequent chiral shape evolution of these crystalline islands, supported by a mass transport from the type-I to type-II islands has been observed. It has been found that this shape anisotropy and two-dimensional chirality in the growth of PnQ type-II islands are related to asymmetric mass incorporation, associated with molecular tilt in surface plane. The real-time LEEM observations supported by the DFT calculations strongly suggest that the long edges of anisotropic islands align along the directions of easier molecule incorporation or lowest kink formation energy at the bottom layer of bilayer PnQ crystal structure, rather than along the steps with the lowest energy. The observed left-handed or right-handed chirality are associated with the particular (upward or downward) orientation of the c-axis of the triclinic PnQ unit cell and they are induced by the selective mass incorporation of the molecules at the opposite long edges of type-II islands. The resulting ring-like island shape evolution originates from the gradual rotation of crystallites at a growth tip. This is most likely associated with an asymmetric arrangement of dislocations at one side of the island, with the opposite edge being locally parallel to a kinetically favored growth direction related to in-plane molecular packing. [1] D.K. Hwang et al., Appl. Surf. Sci. 244 (2005) 615.[2] A. Al-Mahboob et al., Surf. Sci. 601 (2007) 1311.
5:15 PM - W1.6
Organic Supramolecular Nano Architectures: A LEEM Study.
Fawad Khokhar 1 , Raoul van Gastel 1 , Bene Poelsema 1
1 Solid State Physics , University of Twente, Enschede Netherlands
Show AbstractSupramolecular chemistry is a powerful methodology that provides controlled generation of two-dimensional nanostructures with tailor made properties based on bottom-up growth principles [1]. In this methodology, organic molecular building blocks self-assemble into nanostructures via non-covalent directional interactions, e.g., hydrogen bonding [2]. Intermolecular and surface-molecule interactions play a vital role in the final morphology of the resulting organic nanostructures. These nanostructures are attracting attention since they can be exploited in applications such as nanopatterning, surface templating, heterogeneous catalysis, and sensing or molecular recognition, etc, [1]. The nature of intermolecular interactions is well understood, however, the influence of the substrate requires more thorough investigations as they have a fundamental role in determining the growth mechanism of such nanostructures. We used Low Energy Electron Microscope (LEEM) to study the growth of organic nanostructures. LEEM is a powerful tool to gain insights into a variety of dynamical processes on surfaces [3]. Its ability of real time imaging and high resolution makes it a unique tool to study growth processes of nanometer-sized structures. We deposited 4, 4’-biphenyldicarboxylic acid (BDA) on Cu (001) at room temperature. Benzene rings in this organic molecule are responsible for its flat adsorption on surfaces and the carboxylic acid end groups facilitate its intermolecular bonding [4]. We observed distinctive primary and secondary nucleation, growth of nucleated islands and finally coalescence during deposition. Post-deposition behavior of islands and nucleation was studied by annealing at different temperatures and subsequent cooling of the surface. We found that post deposition nucleation and growth of islands occur as a function of the surface temperature. We also observed that nuclei were smaller in number; however subsequent islands were bigger in size. These results have paved the way for more detailed experiments in near future. These will help us to understand the influence of the substrate on nucleation and nucleated islands during and after deposition. [1] S. Stepanow, N. Lin, F. Vidal, A. Landa, M. Ruben, J.V. Barth, and K. Kern, Nano Lett., 5, 5,901-904, 2005.[2] J.V. Barth, G. Costantini and K. Kern, Nature, 437, 671-679,2005. [3] R. J. Phaneuf and A. K. Schmid, Physics Today, 56,50-55, 2003.[4] J.V. Barth, J. Weckesser, N. Lin, A. Dmitriev and K. Kern, Appl. Phys. A 76, 645– 652 , 2003.
5:30 PM - W1.7
Real-Time Observation of PTCDA Growth on Ag(111) - a SMART Investigation.
Pierre Levesque 1 , Helder Marchetto 2 , Ullrich Groh 3 , Florian Maier 3 , Thomas Schmidt 3 , Rainer Fink 4 , Helmut Kuhlenbeck 5 , Eberhard Umbach 3 , Hans-Joachim Freund 5
1 Chimie, Université de Montréal, Montréal, Quebec, Canada, 2 , Diamond Light Source Ltd. , Didcot, Oxfordshire, United Kingdom, 3 Experimentelle Physik II, Universität Würzburg, Würzburg Germany, 4 Physikalische Chemie II, Universität Erlangen-Nürnberg, Erlangen Germany, 5 Chemische Physik, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin Germany
Show AbstractOrganic thin film morphologies and organic-metal interfaces play an important role in the emerging field of organic electronics and optoelectronics. The electronic properties of these systems are largely influenced by film properties like film thickness, roughness, dislocation density, molecular orientation or crystal structure. Due to the polymorphism and variety of structures observed in molecular crystals, the detailed understanding of growth and interface properties requires combined microscopic and spectroscopic investigations like implemented in the SMART spectromicroscope. Especially the (X)PEEM/LEEM methods are particularly well suited to study organic growth. Real-time laterally resolved experiment allows observing growth dynamics including metastable structures. Although the basic contrast mechanisms of PEEM and LEEM imaging have been often discussed for metal and semiconductor surfaces, no detailed analysis of the organic-metal interfaces is presently available.As an example system, the growth of PTCDA on a Ag(111) surface has been studied in situ and in real-time by the SMART at selected sample temperatures ranging from -50 to 120 °C. Whereas in the low temperature range mound like structure are formed, the film grows in a Stranski-Krastanov mode above room temperature, ie. two completed layers followed by three dimensional islands. Using proper contrast mechanism in LEEM, nucleation sites can be directly correlated to the surface morphology and defects. Further on, we report surprising observations like reduced sticking coefficient, metastable layers, internal crystal structures, and dynamic changes within the layers. Differences in the growth and the temperature dependence are discussed. Contrast mechanisms leading to the presented results are also addressed.Project funded by BMBF under contract no. 05 KS4WWB/4.
5:45 PM - W1.8
Competitive Adsorption of Protein and Peptide to Polystyrene-poly(methyl methacrylate): A Quantitative X-ray Spectromicroscopy Study.
Bonnie Leung 1 , Adam Hitchcock 1 , John Brash 2 , Andreas Scholl 3 , Andrew Doran 3 , Peter Henklein 4 , Joerg Overhage 4 , Kai Hilpert 4 , John Hale 4 , Robert Hancock 4
1 BIMR, McMaster University, Hamilton, Ontario, Canada, 2 School of Biomedical Engineering, McMaster University, Hamilton, Ontario, Canada, 3 Advanced Light Source, Berkeley Lab, Berkeley, California, United States, 4 Microbiology, University of British Columbia, Vancouver, Ontario, Canada
Show AbstractNear-edge X-ray absorption fine structure (NEXAFS) spectra obtained at high spatial resolution (~80 nm) with an X-ray photoemission electron microscope (X-PEEM) is an excellent tool to quantitatively probe sub-monolayer proteins adsorbed on a phase segregated polymer system [1,2]. The adsorption of human serum albumin (HSA) to a polystyrene (PS) - poly(methyl methacrylate) (PMMA) model biomaterial thin film has been well characterized, showing selective adsorption of HSA to the interface between PS and PMMA [2]. The C 1s NEXAFS spectrum of proteins is easily differentiated from those of polysaccharides, lipids and nucleic acids [3]. However, it is much more difficult to differentiate among different proteins due to the large extent of spectral averaging over relatively similar sequences. In order to use NEXAFS microscopy to differentiate proteins or peptides there must be sufficiently different spectra, arising from large differences in their amino acid sequences. We have recently demonstrated that it is possible to chemically map an arginine-rich peptide (Sub-6 RWWKIWVIRWWR-NH2) against a background of human serum albumin (HSA) protein using distinctive aspects of the C 1s spectra [4]. We are using spectromicroscopy to investigate the competitive adsorption of proteins and peptides on biomaterial surfaces. A PS-PMMA thin film was exposed to an aqueous mixture of HSA and Sub-6 at pH ~ 7 under various concentrations and exposure conditions. Our preliminary PEEM results reveal that the Sub-6 peptide (which has a net positive charge of +5 at physiological pH) preferentially adsorbs on the polar PMMA region and the interface between PS and PMMA. At high concentrations of protein (0.05 mg/mL) and peptide (0.01 mg/mL), the highly negatively charged HSA (~ -20) forms an adduct with Sub-6, resulting in an enhanced adsorption of peptide across the entire surface, while at low concentrations (10-5 mg/mL peptide, with an HSA concentration of 0.05 mg/mL) the amount of protein increases significantly on the PS region as the peptide preferentially adsorbs to the PMMA and interface region. Acknowledgements: This research is funded by the Natural Science and Engineering Research Council (NSERC, Canada.) All X-ray spectromicroscopy studies were performed using PEEM2 at the Advanced Light Source (ALS), which is supported by Basic Energy Sciences, DoE (US). References1. Morin, et al. J. Electron. Spec. 2004, 137-140, 785.2. Li, et al. J. Phys. Chem B 2006, 110, 167633. Lawrence, et al. Appl. Env. Microbiology 2003, 69, 5543. 4. Stewart-Ornstein, et al. J. Phys. Chem. B. 2007, 111 7691-7699.
Symposium Organizers
David L. Adler DLA Instruments Corporation
Ernst Bauer Arizona State University
Gary L. Kellogg Sandia National Laboratories
Andreas Scholl Lawrence Berkeley National Laboratory
W3: Semiconductor and Device Physics
Session Chairs
David Adler
Marian Mankos
Tuesday PM, March 25, 2008
Room 3011 (Moscone West)
2:30 PM - **W3.1
Low Energy Electron Microscopy for Semiconductor Applications.
Marian Mankos 1 , Vassil Spasov 1 , Liqun Han 1 , Shinichi Kojima 1 , Ximan Jiang 1 , Salam Harb 1 , Luca Grella 1 , Cory Czarnik 1
1 , KLA-Tencor, San Jose, California, United States
Show AbstractA novel low energy electron microscope (LEEM) aimed at improving the throughput and extending the applications for semiconductor devices has been developed. A dual beam approach, where two beams with different landing energies illuminate the field of view, is used to mitigate the charging effects when the LEEM is used to image semiconductor substrates with insulating or composite (insulator, semiconductor, metal) surfaces. We have experimentally demonstrated this phenomenon by imaging a variety of semiconductor device wafers without deleterious charging effects. Results from several important semiconductor device layers will be illustrated in detail.
3:00 PM - W3.2
Low-Energy Electron Microscopy Imaging of Biased Semiconductor Test Structures.
M. Anderson 1 , G. Kellogg 1 , C. Nakakura 1
1 , Sandia National Laboratories, Albuquerque, New Mexico, United States
Show AbstractLow-energy electron microscopy (LEEM) has proven to be a powerful tool for imaging surfaces with high resolution (~8nm) and high throughput. The sensitivity of LEEM to surface morphology, differences in work function, and surface charge variations make this an ideal instrument for the inspection and characterization of semiconductor devices. In particular, source, drain, and channel profiles are key design elements for transistors that can be probed with the LEEM. In this talk, we will expand upon previous work on grounded Si diode test structures, to imaging these structures under forward and reverse-biasing conditions. Diode test structures were fabricated by implanting As and/or B into Si(100) p-type substrates to construct n+/p junctions. Voltages from -5 V to +5 V were applied directly to the diode structures so the redistribution of charge during device operation could be measured with LEEM. This applied bias should not be confused with the sample bias applied during LEEM imaging (which governs whether the incoming electrons are reflected or penetrating the sample). Changes in the real-time LEEM image due to changes in applied bias are immediate. Observed contract effects induced by the applied bias include changes in width and intensity of the structures. These measurements were compared to scanning capacitance microscopy measurements of the test structures under the same biasing conditions. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company for the United States Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.
3:15 PM - W3.3
The Investigation of Dislocations in Strained Si Thin-films and Nano-Membranes by Low-Energy Electron Microscopy.
Chanan Euaruksakul 1 , Donald Savage 2 , Max Lagally 2
1 Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin, United States, 2 Material Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin, United States
Show AbstractThe formation of misfit dislocations in strained epitaxial films grown on Si (001) substrates generates local uniaxial strain fields in the films near misfit segments. When segments are confined to an interface not too far below the surface, significant strain reaches the surface. For Si(001) such uniaxial strain influences strongly the clean surface reconstruction favoring domains whose surface dimers are compressed. Dark field imaging in low-energy electron microscopy (LEEM) allows the direct determination of relative changes of the population of (1x2) and (2x1) domains, thus inferring local uniaxial strain dynamically in-situ. This allows dislocations to be observed without the need to thin down samples as conventionally done in dislocation imaging using transmission electron microscopy. The ability of LEEM to observe buried dislocations (albeit indirectly) makes it an ideal method to observe initial dislocation formation when films near critical thickness. In addition, when combined with the ability to heat samples to near their melting points it allows us to examine the thermodynamic stability of strained films. We present the use of LEEM to study thermal stability and dislocations in strained Si-on-insulator, SiGe films grown on Si-on-insulator substrates, and strain-sharing Si nano-membranes, a new type of substrates in which strain is applied to Si without introducing dislocations.
3:30 PM - W3.4
XPEEM at Energy Converting Interfaces.
Christian Pettenkofer 1
1 SE6, Hahn-Meitner-Institut, D-14109 Berlin Germany
Show Abstract3:45 PM - W3.5
Chemical Characterization of Scanning Probe Fabricated Nanostructures Using Photoemission Electron Microscopy.
Marco Rolandi 1 2 , Andreas Scholl 3 , Jean Frechet 1 2
1 College of Chemistry, University of California, Berkeley, Berkeley, California, United States, 2 Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States, 3 Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California, United States
Show AbstractDuring the ongoing quest for device miniaturization, the atomic force microscope (AFM) has risen as a promising tool for patterning nanostrucutres with progressively higher resolution. Several techniques have been developed that involve physical or chemical surface modification of a variety of substrates. In general, the tip is used to define a localized environment in proximity of the surface where chemistry can occur on a few thousand molecules at the time. A fundamental understanding of the reactions in such a unique environment requires a careful characterization of the products. We will present spectroscopic analysis of carbon based nanostructures fabricated via the high electric field modification of organic precursors by a biased AFM probe. Near edge x-ray absorption fine structure spectra with high spatial resolution were acquired with the PEEM-2 at the Advanced Light Source, Lawrence Berkeley National Laboratory. The effects of solvent composition and surface properties on nanostructure chemistry will be discussed.
4:30 PM - **W3.6
Time-Resolved Photoemission Microscopy as Sensor for Plasmonic Excitations in Silver Nanostructures.
Frank Meyer zu Heringdorf 1 2 , Liviu Chelaru 1 3 , Simone Moellenbeck 1 , Niemma Buckanie 1 , Dagmar Thien 1 , Michael Horn-von Hoegen 1 2
1 Department of Physics, University of Duisburg-Essen, Duisburg Germany, 2 , Center for Nano-Integration Duisburg-Essen (CeNIDE), Duisburg Germany, 3 , present adress: Institut für Festkörperforschung, Forschungszentrum Jülich, Jülich Germany
Show Abstract5:00 PM - W3.7
Morphology of Graphene Thin Film on SiC(0001).
Taisuke Ohta 1 2 , Farid El Gabaly 3 , Aaron Bostwick 1 , Jessica McChesney 1 2 , Konstantin Emtsev 4 , Andreas Schmid 3 , Thomas Seyller 4 , Karsten Horn 2 , Eli Rotenberg 1
1 Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, California, United States, 2 , Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin Germany, 3 National Center for Electron Microscopy, E. O. Lawrence Berkeley National Laboratory, Berkeley, California, United States, 4 Lehrstuhl für Technische Physik, Universität Erlangen-Nürnberg, Erlangen Germany
Show Abstract5:15 PM - W3.8
Using Photoelectron Emission Microscopy to Probe Field Effects in Carbon Nanotube Field Effect Transistors.
Vinod Sangwan 1 , Vincent Ballarotto 2 , Michael Fuhrer 1 , Ellen Williams 1 2
1 , University of Maryland, College Park, Maryland, United States, 2 , Laboratory for Physical Sciences, College Park, Maryland, United States
Show Abstract5:30 PM - W3.9
Photoelectron- and Thermionic- Emission Microscopy of Barium/Scandium Thin Films on Tungsten.
Martin Kordesch 1 , Joel Vaughn 1
1 Physics and Asronomy, Ohio University, Athens, Ohio, United States
Show Abstract