Symposium Organizers
Heike Riel IBM Research GmbH
Ted Kamins Hewlett-Packard Laboratories
Hongjin Fan University of Cambridge
Saskia Fischer Ruhr-University of Bochum
Claes Thelander Lund University
O1: Growth of III-V Nanowires
Session Chairs
Tuesday PM, March 25, 2008
Room 3002 (Moscone West)
9:30 AM - **O1.1
Synergetic Nanowire Growth.
Erik Bakkers 1 , Magnus Borgstrom 1 2 , George Immink 1 , Bas Ketelaars 1 , Rienk Algra 1
1 , Philips Research Labs, Eindhoven Netherlands, 2 , Lund University, Lund Sweden
Show AbstractInterest in nanowires continues to grow as they hold the promise of monolithic integration of high-performance semiconductors with new functionality into existing silicon technology. Most nanowires are grown using Vapor-Liquid-Solid (VLS) growth, and despite many years of study this growth mechanism remains under lively debate. Especially the role of the metal particle is unclear. For instance, contradictory results have been reported on the effect of particle size on the nanowire growth rate. In these studies, randomly deposited catalyst particles have been used and both an increase, by the ‘mass conservation effect’, and a decrease of the growth rate, by the Gibbs-Thomson effect, have been reported for decreasing particle size. Additionally, nanowire growth from a patterned array of catalysts has shown that small wire-to-wire distances lead to materials competition reducing the growth rate. Here we report on a counterintuitive ‘synergetic’ effect resulting in an increase of the growth rate for decreasing wire-to-wire distance and increasing particle size. By using a refined catalyst pattern we identify three regimes with different mechanisms determining the nanowire growth rate: 1) Material competition between neighbouring wires for the smallest interdistance. 2) ’Diffusion’ limited growth for long interdistance. 3) The synergetic effect at intermediate distances, where the growth rate increases proportionally with the catalyst area fraction. The effect has its origin in the catalytic decomposition of precursors and is applicable to a variety of nanowire materials and growth techniques.
10:00 AM - O1.2
Thermoelectric Power Measurements of One-dimensional Wide Bandgap Semiconducting Nanostructures.
Chul-Ho Lee 1 , Yuri Zuev 2 , Jinkyoung Yoo 1 , Young Joon Hong 1 , Philip Kim 3 , Gyu-Chul Yi 1
1 National CRI Center for Semiconductor Nanorods and Department of Materials Science and Engineering, POSTECH, Pohang Korea (the Republic of), 2 Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York, United States, 3 Department of Physics, Columbia University, New York, New York, United States
Show AbstractTuesday, March 25Transferred Poster O7.4 to O1.2 @ 9:00 AMThermoelectric Power Measurements of One-dimensional Wide Bandgap Semiconducting Nanostructures. Chul-Ho Lee
10:15 AM - O1.3
Nucleation Mechanism of Ga-assisted MBE Growth of GaAs Nanowires.
Carlo Colombo 1 , Jordi Arbiol 2 3 , Joan Ramon Morante 3 , Gerhard Abstreiter 1 , Anna Fontcuberta i Morral 1
1 Walter Schottky Institut, Technical University of Munich, Garching Germany, 2 TEM-MAT, Serveis Cientificotècnics, University of Barcelona, Barcelona Spain, 3 EME/CeRMAE/IN2UB, Departament d’Electrònica, University of Barcelona, Barcelona Spain
Show Abstract10:30 AM - O1.4
On the Nucleation Stage of GaAs NWs and GaAs/AlGaAs Prismatic Quantum Heterostructures Grown by Ga-Assisted Molecular Beam Epitaxy.
Jordi Arbiol 1 2 , Anna Fontcuberta i Morral 3 , Carlo Colombo 3 , Dance Spirkoska 3 , Gerhard Abstreiter 3 , Joan Ramon Morante 2
1 TEM-MAT, Serveis Cientificotecnics, Universitat de Barcelona, Barcelona, CAT, Spain, 2 EME/CeRMAE/IN2UB, Departament d'Electronica, Universitat de Barcelona, Barcelona, CAT, Spain, 3 Walter Schottky Institut, Technische Universität München, Garching Germany
Show Abstract10:45 AM - O1.5
Influence of Si- and Mg-impurities on the Growth Mechanism of GaN Nanorods on Si (111).
Florian Furtmayr 1 , Martin Vielemeyer 1 , Martin Stutzmann 1 , Jordi Arbiol 2 3 , Sonia Estrade 3 , Francesca Peiro 3 , Morante Joan Ramon 3 , Martin Eickhoff 1
1 Walter Schottky Institut, Technische Universitaet Muenchen, Garching Germany, 2 EME/CeRMAE/IN2UB, Dept. d'Electronica, Universitat de Barcelona, Barcelona, CAT, Spain, 3 TEM-MAT, Serveis Cientificotecnics, Universitat de Barcelona, Barcelona, CAT, Spain
Show Abstract11:30 AM - O1.6
Understanding the Morphology of Compositionally Modulated Heterostructure Nanowires.
Frances Ross 1 3 , Kimberly Dick 2 , Mark Reuter 1 , Suneel Kodambaka 1 4 , Knut Deppert 2 , Lars Samuelson 2 , Werner Seifert 2 , Reine Wallenberg 3
1 , IBM TJ Watson Research Center, Yorktown Heights, New York, United States, 3 Polymer & Materials Chemistry/nCHREM, Lund University, Lund Sweden, 2 Solid State Physics, Lund University, Lund Sweden, 4 Materials Science and Engineering, UCLA, Los Angeles, California, United States
Show Abstract11:45 AM - O1.7
In situ Crystallographic Phase and Orientation Analysis of GaAs Nanowires by SEM/EBSD.
Scott Sitzman 1 , Sergey Prikhodko 2 , Vincent Gambin 3 , Suneel Kodambaka 2
1 , Oxford Instruments NanoAnalysis, Concord, Massachusetts, United States, 2 Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, California, United States, 3 , Northrop Grumman Space Technology, Redondo Beach, California, United States
Show Abstract12:00 PM - **O1.8
Growth and Optical Properties of InP/InAs Multi-core Shell Nanowires Grown by Selective Area MOVPE.
Takashi Fukui 1 , Shinjiro Hara 1 , Junichi Motohisa 1
1 Research Center for Integrated Quantum Electronics , Hokkaido University, Sapporo, Hokkaido, Japan
Show Abstract12:30 PM - O1.9
Si-doping Effect on GaN and InN MBE-grown Nanowires.
Raffaella Calarco 1 , Ralph Meijers 1 , Toma Stoica 1 , Thomas Richter 1 , Kulandiavel Jeganathan 3 , Ratan Debnath 1 , Michel Marso 1 , Eli Sutter 2 , Hans Lüth 1
1 Institute of Bio- and Nanosystems (IBN-1) and Center of Nanoelectronic Systems for Information Technology (cni), Research Centre Juelich GmbH, Juelich Germany, 3 Department of Physics, Bharathidasan University, Trichirappalli India, 2 Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York, United States
Show Abstract12:45 PM - O1.10
GaN and Ga2O3 Nanowire and Nanoribbon Growth from Ion-implanted Catalyst.
Yongho Choi 1 , Jason Johnson 1 , Ant Ural 1
1 Electrical and Computer Engineering, University of Florida, Gainesville, Florida, United States
Show AbstractControlled growth of semiconductor nanowires remains one of the biggest challenges in bottom-up assembly of nanowire-based devices. Chemical vapor deposition (CVD) is a very attractive method for growing semiconductor nanowires. An essential component of the CVD process is the metal catalyst nanoparticles placed on the substrate for nucleating the growth of semiconductor nanowires. These catalysts are typically prepared by depositing a metal layer of a few nanometers by evaporation, followed by annealing to form metal particles of nanoscale size. Alternatively, monodispersed metal nanoparticles dispersed in a liquid solution are deposited on the substrate to form the catalyst. In order to control the origin of nanowires during CVD growth, the catalyst is typically patterned by lithography into small “islands”. However, it is not possible to pattern the liquid solution-based catalyst into very small dimensions and the thin film catalyst into nonplanar three-dimensional (3D) device structures, such as high aspect ratio trenches. An alternative solution is to use ion implantation, a well-established technique in silicon microfabrication, and subsequent annealing to create catalyst nanoparticles. Ion-implanted catalyst is much easier to pattern into very small features and over high aspect ratio topography compared to other types of catalyst, and it offers extremely accurate control of the number of atoms introduced into the substrate (the dose). In this talk, we present experimental evidence that semiconductor nanowires and nanoribbons can indeed be produced by the process of ion implantation, subsequent annealing, and CVD growth. In particular, we implant iron ions at various doses and energies into thermally grown SiO2 layers on silicon substrates. We then use CVD to grow GaN and Ga2O3 nanowires and nanoribbons from these ion implanted substrates. Using atomic force microscopy (AFM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), selected area electron diffraction (SAED), energy dispersive x-ray spectroscopy (EDS), and X-ray diffraction (XRD), we systematically study the effect of ion implantation dose and energy, and anneal and growth time and temperature on the structural properties of the nanoscale clusters, as well as the nanowires and nanoribbons nucleated from these clusters.Since ion-implantation can be easily masked by lithography, this technique of nucleating nanowire growth opens up the possibility of controlling the origin of nanowires at the nanometer scale and of integrating nanowires into nonplanar 3D device structures. Ion implantation, which can easily be integrated with silicon processing and scaled to larger substrates, could offer significant technological advantages as a method to form catalyst nanoparticles for a wide range of nanoscale device applications.
O2: Growth of Si, Ge Nanowires
Session Chairs
Tuesday PM, March 25, 2008
Room 3002 (Moscone West)
2:30 PM - **O2.1
Ge Nanowire Growth Kinetics: New Insights Into The Vapor-Liquid-Solid Process.
Suneel Kodambaka 1
1 , UCLA, Los Angeles, California, United States
Show AbstractGrowth of nanowires is commonly attributed to the vapor-liquid-solid (VLS) process, where material from the vapor is incorporated as a solid via a liquid catalyst, commonly a low-melting binary eutectic alloy. Despite several years of research, some of the key and basic aspects of nanowire growth remain unresolved. For example, the state of the catalyst and the rate-limiting process are not clear even for relatively simple elemental materials such as Ge. Here, we present recent in situ transmission electron microscopy (TEM) studies of Au-catalyzed growth of Ge nanowires. All our experiments are carried out in an ultra-high vacuum TEM (UHV-TEM) equipped with in situ physical and chemical vapor deposition facilities. Ge nanowires are grown on clean Au-covered Si substrates using digermane gas. TEM images of the wires and the catalyst droplets are collected at video rate as a function of growth pressure, temperature and gas environment.Direct TEM observations have provided new insights into the Ge wire growth mechanisms. We find that Ge wires grow both in the presence of solid as well as liquid catalysts, although at different rates. The existence of liquid AuGe catalysts at temperatures below the bulk Au-Ge alloy eutectic temperature is favored at high Ge fluxes. Ge wire morphology and growth orientation can be controllably varied with Ge flux and temperature. We also observe larger diameter Ge wires to grow faster than the smaller diameter wires. We suggest that the Ge wire growth kinetics is governed by the Ge supersaturation in the catalyst.*Work done at the IBM T. J. Watson Research Center, Yorktown Heights, NY 10598 in collaboration with J. Tersoff, M. C. Reuter, and F. M. Ross.
3:00 PM - O2.2
Axial Si/Ge Nanowire Heterostructures: Synthesis, Structure and Properties.
S. Picraux 1 , S. Choi 1 , J. Huang 2 , J. Swadener 1
1 Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico, United States, 2 Center for Integrated Nanotechnologies (CINT), Sandia National Laboratories, Albuquerque, New Mexico, United States
Show Abstract3:15 PM - O2.3
Determination of Non-uniform P Atom Distribution in VLS-grown Ge Nanowires.
Daniel Perea 1 , Jessica Lensch-Falk 1 , Lincoln Lauhon 1
1 Materials Science & Engineering, Northwestern University, Evanston, Illinois, United States
Show Abstract3:30 PM - O2.4
Phase Equilibrium and Nanowire Growth
Edwin Schwalbach 1 , Peter Voorhees 1
1 Materials Science & Engineering, Northwestern University, Evanston, Illinois, United States
Show AbstractKnowledge of the equilibrium conditions between liquid catalysts and solid nanowires is necessary to fully understand the Vapor-Liquid-Solid (VLS) growth mechanism. A thermodynamic treatment of this system is carried out, and the geometry dependent equilibrium phase diagrams of both Au-Si and Au-Ge nanowires are calculated as a function of wire diameter. Factors influencing equilibrium between liquid and solid include, surface energies, surface stress, and geometric factors. Elastic stresses in the solid wire are a result of surface stress that exist at the solid-vapor interface as well as the elevated pressure in the liquid catalyst due to the curved liquid-vapor interface. Both of these effects scale with the inverse of the wire diameter, and thus become significant for small wires. We find that the solid-vapor and liquid-vapor interfacial energies also play a major role in determining the phase diagram. The eutectic temperature is estimated as a function of wire diameter, and sub-eutectic temperature growth is considered in light of several recent experimental findings. The Gibbs-Thompson depression of the eutectic temperature can be 80K or more for a 30nm diameter wire, a significant fraction of the reported undercooling with respect to the bulk eutectic temperature. Also, the equilibrium solubility of Au in Si, a parameter that is potentially important for electrical properties, is found to decrease as wire diameter decreases. Finally, we consider the homogeneous nucleation of Au or Si\Ge within the liquid catalyst below the wire-diameter-dependent eutectic temperature. An interesting consequence of the shape dependent nature of the phase diagram is that the driving force for nucleation of Au or Si\Ge in the liquid catalyst does not vanish at the equilibrium phase boundary between the liquid droplet and the solid wire. Consequences of this are explored.
3:45 PM - O2.5
Underlying Mechanisms of Gold Catalyzed Silicon Nanowire Growth: First Principles-based Atomistic Modeling.
Soohwan Lee 1 , Gyeong Hwang 1
1 chemical engineering, the university of texas, Austin, Texas, United States
Show Abstract4:30 PM - O2.6
Detection of Gold Atoms in VLS-Grown Silicon Nanowires.
Eric Hemesath 1 , Jon Allen 1 , Daniel Perea 1 , Mhairi Gass 3 , Ziyou Li 2 , Jessica Lensch-Falk 1 , Peng Wang 3 , Feng Yin 2 , Richard Palmer 2 , Andrew Bleloch 3 , Lincoln Lauhon 1
1 Materials Science and Engineering, Northwestern University, Evanston, Illinois, United States, 3 SuperSTEM Facility, Daresbury Laboratory, Daresbury United Kingdom, 2 Nanoscale Physics Research Laboratory, University of Birmingham, Birmingham United Kingdom
Show AbstractSemiconductor nanowires are the focus of intense research and development due to their potential as building blocks of nanoscale devices. Although a number of synthesis routes exist, the vapor-liquid-solid (VLS) growth mechanism has been one of the most broadly exploited due to the ability to synthesize single component and heterostructured nanowires over a wide range of semiconductors and oxides. Unintentional contamination by the metal catalyst remains a concern, however, particularly for Au, which is very detrimental to the electronic properties of nanowire devices even in ppb concentrations. Traditional approaches to measure bulk concentrations of Au in the ppb range cannot be applied to nanowires. To address this important issue, we have imaged single Au atoms in Au-catalyzed silicon nanowires using high-angle annular dark-field (HAADF) imaging on an aberration-corrected scanning transmission electron microscope (STEM). In projection images of single crystal silicon nanowires, Au atoms were observed in atomic columns with higher intensity compared to neighboring columns. The excess intensity above the silicon nanowire background is consistent with scattering from single Au atoms. The reduced depth of field in the aberration-corrected instrument was exploited to determine the vertical position of Au atoms by focal series imaging. The concentration of Au atoms was determined to be greater than the equilibrium bulk solubility of Au in silicon. Additionally, Au atoms were observed to strongly segregate to defect sites in a number of twinned nanowires. Interestingly, Au atoms at the twin interface were found in pairs of atomic lines with a periodic spacing between the atoms, providing insights into the mechanism of twin growth in group IV nanowires. Electron beam induced current (EBIC) microscopy was used to measure the minority carrier diffusion length of n-type silicon nanowires as a function of diameter. We found that minority carrier diffusion is controlled by surface recombination, rather than bulk Au impurity recombination, consistent with observed concentration of Au and the expected surface recombination velocity of the native oxide. These findings provide important guidance to the further development and optimization of silicon nanowires for electronic applications.
4:45 PM - O2.7
Three-dimensional Mapping of Catalyst Concentration in VLS Grown Si Wires via NanoSIMS.
Morgan Putnam 1 , Brendan Kayes 1 , Michael Filler 1 , Michael Kelzenberg 1 , Yunbin Guan 1 , Nathan Lewis 1 , John Eiler 1 , Harry Atwater 1
1 , Caltech, Pasadena, California, United States
Show Abstract5:00 PM - O2.8
Phase Diagram of Nanoscale Alloy Particles Used for Vapor-Liquid-Solid Growth of Semiconductor Nanowires.
Eli Sutter 1 , Peter Sutter 1
1 Eli Sutter, Brookhaven National Laboratory, Upton, New York, United States
Show AbstractSemiconductor nanowires (NWs) – promising materials for a variety of quantum devices benefiting from the 1D confinement and from a large surface-to-volume ratio – have been realized successfully by metal catalyst assisted vapor-liquid-solid (VLS) growth. Despite of its widespread use for the synthesis of NWs from a variety of materials, key aspects of the VLS growth process remain poorly understood, primarily due to the fact that, in contrast to studies on conventional thin film deposition, measurements with nanometer spatial resolution are needed to analyze the mechanisms of NW growth. Central to the VLS process is a liquid metal-semiconductor binary alloy drop whose interface to the semiconductor wire represents the NW growth front. The properties of the alloy drop at or close to thermodynamic equilibrium with the adjacent NW, represented by the phase diagram of the binary alloy, govern important aspects of VLS NW growth. A key parameter is the equilibrium composition of the alloy, given by the liquidus line in the phase diagram, as it controls the drop size. The drop size, in turn, defines the diameter of the growing NW, a key characteristic that governs, via quantum confinement, the electronic structure of the wire. Given the small drop size, typically few tens of nanometers, the phase diagram of the corresponding bulk alloy cannot be expected to accurately reflect the behavior of the VLS seed drop.Here we present real-time transmission electron microscopy observations with high resolution of Au-Ge alloy drops at the tips of Ge nanowires during high-temperature annealing. The analysis of the temperature dependent exchange of Ge between a Ge nanowire and the Au-Ge drop allows us to directly determine the liquidus in the phase diagram of the nanoscale binary alloy drop. We find that the phase diagram deviates significantly from that of the bulk alloy, which explains discrepancies often observed between actual growth results and predictions on the basis of the bulk phase diagram. To illustrate the predictive power resulting from knowledge of the true phase diagram of the nanoscale VLS seed drop, we demonstrate control over the local position-dependent diameter of the growing nanowire.
5:15 PM - O2.9
An Environmental Stage for the Dynamic TEM: Controlled In Situ Nanowire Growth at Nanosecond Time Scales.
Mitra Taheri 1 2 , Bryan Reed 1 , Pushkarraj Deshmukh 5 , William Wong 4 , Paul Fischione 5 , Nigel Browning 1 3
1 Chemistry, Materials, Earth & Life Sciences, Lawrence Livermore National Laboratory, Livermore, California, United States, 2 Materials Science & Engineering, Drexel University, Philadelphia, Pennsylvania, United States, 5 , Fischione Instruments, Pittsburgh, Pennsylvania, United States, 4 , Xerox-PARC, Palo Alto, California, United States, 3 Chemical Engineering & Materials Science, University of California-Davis, Davis, California, United States
Show Abstract5:30 PM - O2.10
Solution-Liquid-Solid (SLS) Growth of Silicon Nanowires.
Andrew Heitsch 1 2 , Dayne Fanfair 1 2 , Hsing-Yu Tuan 1 2 , Brian Korgel 1 2
1 Chemical Engineering, University of Texas - Austin, Austin, Texas, United States, 2 Texas Materials Institute and Center for Nano- and Molecular Science and Technology, University of Texas - Austion, Austin, Texas, United States
Show AbstractSilicon (Si) nanowires were synthesized colloidally by solution-liquid-solid (SLS) growth in a conventional solvent under atmospheric pressure on a Schlenk line using 2 nm diameter gold nanocrystals as seeds. Milligrams of Si nanowires could be produced in a single reaction. Silicon nanowires up to 5 micrometers long with diameters ranging between 5 nm and 30 nm are typical for these reactions. X-ray diffraction confirmed that the nanowires are composed of diamond cubic silicon. High resolution transmission electron microscopy of the nanowires shows that they are single crystal with few defects and have relatively clean surfaces. The primary growth direction of the nanowires is <111>. Energy dispersive X-ray spectroscopy (EDS) revealed Au located only at the tips of the Si nanowires, further evidence of the SLS mechanism for nanowire growth. Although Si nanowires can be synthesized in solvents under pressure at high temperature by the supercritical fluid-liquid-solid (SFLS) process, this is the first example of Si nanowire synthesis in a solvent at ambient pressure that we are aware of. In this presentation, we will discuss the importance of various parameters on the yield and quality of the nanowires, including the role of temperature, the silicon reactant, the seed metal, the silicon to gold ratio, and the solvent.
5:45 PM - O2.11
Hetero-Branched Nanowires: General Synthesis and Functional Devices.
Xiaocheng Jiang 1 , Bozhi Tian 1 , Charles Lieber 1 2
1 Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States, 2 School of Engineering and Applied Science, Harvard University, Cambridge, Massachusetts, United States
Show AbstractBranched nanostructures represent important, three dimensional building blocks for nanoscale science and technology. Specifically, it is possible to create unique functionality at a branch point through the rational choice and controlled synthesis of backbone/branch materials. Here, we report a general multi-step growth of diverse hetero-branched nanowire structures with different backbone/branch options including semiconductor/semiconductor, semiconductor/metal, semiconductor/oxide/semiconductor and semiconductor/oxide/metal, via either vapor- or solution-phase synthetic routes. Scanning electron microscopy studies showed that the hetero-branched structures can be obtained in high-yield, while transmission electron microscopy and energy-dispersive X-ray spectroscopy analyses further demonstrated sharp interfaces between backbone and branches. Interestingly, epitaxial interfaces were observed for most semiconductor/semiconductor (IV/IV, IV/III-V, IV/II-VI) hetero-branched structures despite lattice mismatch up to 8.1 %. The epitaxial nature of these interfaces suggests effective relaxation of strain in the branch structure, and was further investigated with stress field modeling. In addition, electrical transport studies of hetero-branch devices based on p-Si/n-Ge (n-GaAs, n-CdSe, Au) and p-Si/SiO2/n-Ge (Au) nanostructures demonstrated well-defined and predictable diode and field effect transistor characteristics. The integration of these elements via multi-branch inputs further enabled the realization of more complex nanoscale devices, including logic gates, light-emitting diode arrays and biological sensors. The potential of hetero-branched nanowires as building blocks for complex integrated nanosystems will be discussed.
Symposium Organizers
Heike Riel IBM Research GmbH
Ted Kamins Hewlett-Packard Laboratories
Hongjin Fan University of Cambridge
Saskia Fischer Ruhr-University of Bochum
Claes Thelander Lund University
O7: Poster Session: III-V Nanowires: Devices and Applications
Session Chairs
Wednesday PM, March 26, 2008
Exhibit Hall (Moscone West)
1:00 AM - O7.1
The Effect of Nanoscale Protrusions on Field-EmissionProperties for GaN Nanowires.
Kuo Hao Lee 1 2 , Cheng Da Shin 1 2 , In Gann Chen 1 2 , Bean Jon Li 3
1 Department of Material Science and Engineering, National Cheng Kung University, Tainan Taiwan, 2 Frontier Material and Micro/NanoScience and, National Cheng Kung University, Tainan Taiwan, 3 Material and Chemical Research Laboratories, Industrial Technology Research Institute, Hsin Chu Taiwan
Show Abstract1:00 AM - O7.10
Raman Spectroscopic Analysis of p-doped Bridged InP Nanowire.
Ataur Sarkar 1 , Sungsoo Yi 2 , M. Saif Islam 1 , Albert Talin 3
1 Electrical and Computer Engineering, University of California, Davis, California, United States, 2 Advanced Laboratories, Philips Lumileds Lighting Company, San Jose, California, United States, 3 , Sandia National Laboratories, Livermore, California, United States
Show AbstractMagnesium (Mg) doped InP nanowires were synthesized in a low pressure MOCVD reactor using gold catalyst and bridged between prefabricated single crystal vertical silicon electrodes. Raman spectroscopic study using a green laser (λ~ 532 nm) was performed to investigate nanowire surface morphology, carrier concentrations and mobilities and post-growth electrical isolation between the electrodes. First order TO-phonon and LO-phonon-plasmon peaks are observed at 305 cm-1 and 345 cm-1, respectively, and are consistent with those for bulk single crystal InP. LO coupling is observed weaker than TO coupling with a nominal TO/LO peak ratio of 1.1. TO peak intensity is believed to be influenced by carrier concentration and misorientation of the nanowires. Long nanowires (length ~2 µm) showed a bottom broadening up to ~20 cm-1 of the TO coupling mode due to the energy dispersion in the shifted Stokes spectrum originating from surface depletion (or insulating layer) and misorientation of the nanowires. Raman scattering measurements indicate a trace of uncatalyzed InP on the insulating SiO2 substrate and exactly conform to the electrical measurements of leakage currents of few pA before the growth and hundreds of nA after the growth. We observed geometry dependent TO-phonon interaction in some samples with tapered nanowires having lowest diameter (~10 nm) at the tip with Au catalyst. Tapered nanowire tip demonstrated strongest response because of more pronounced TO- phonon interaction due to smaller tip geometry. The residual Au catalyst at the tip may also enhance the interaction process. From the primary results generated, we find Raman spectroscopy as a powerful analytical tool for the characterization of InP nanowires. More work is under way for detailed analysis of the surface morphology, carrier density and mobility of the fabricated devices.
1:00 AM - O7.11
Controlled Assembly and Characterization of Single GaN Nanorod p-n Junction Diodes.
Hon-Way Lin 1 , Yu-Chen Yang 1 , Shangjr Gwo 1
1 Department of Physics, National Tsing-Hua University, Hsinchu Taiwan
Show AbstractRecently, there is intense research interest in one-dimensional III-nitride semiconductors nanostructures due to their superior material properties and promising potential for device applications. The fundamental requirement for semiconductor nanowire and nanorod diode applications is the formation of well characterized p-n junction. Although it is known that GaN can be doped as n- and p-type semiconductors, the characteristics of single GaN nanorod p-n junctions are relatively unexplored because of difficulties in synthesizing and assembling such type of nanorod devices. In this work, the catalyst-free GaN nanorod array samples were grown on Si(111) substrates using plasma-assisted molecular beam epitaxy (PAMBE). By adding Si and Mg in the nanorod arrays as n- and p-type dopants during the PAMBE growth process, vertically aligned GaN nanorod p-n junction can be formed. The average length and width of GaN nanorods used here is 2 μm and ~60 nm, respectively. We will present recent results of manipulation, assembly, and characterization of single GaN nanorods by using a four-probe nanomanipulation system installed in a field-emission scanning electron microscope (FE-SEM). In this electrostatic manipulation/assembly process, the p-n junction interfaces in nanorods can be directly observed by FE-SEM with the assistance of a conducting probe. An imaging mechanism has been proposed by us and will be presented here. To further confirm the p-n junction behavior, the current-voltage characterization was also conducted. The measured nanorods were first placed across two Ti pads deposited on 1-μm-thick thermally oxidized Si substrates by means of the nanomanipulator in FE-SEM. Subsequently, Ti/Au and Ni/Au Ohmic contacts were deposited on the contact pads using standard electron-beam lithography and lift-off techniques. Both electrical and optical properties of the single GaN nanorod p-n junctions have been obtained and will be compared here.
1:00 AM - O7.12
Vacancy Ordering in III2VI3 Nanowires.
Hailin Peng 1 , Chong Xie 1 , David Schoen 1 , Yi Cui 1
1 , Stanford University, Stanford, California, United States
Show Abstract1:00 AM - O7.13
III-V Semiconductor Nanowire Heterostructures on Si.
Parsian Katal Mohseni 1 , Ray LaPierre 1
1 Centre for Emerging Device Technologies, Department of Engineering Physics, McMaster University, Hamilton , Ontario, Canada
Show AbstractThe need to understand and grow nanowire heterostructures for optoelectronic device applications, through highly controlled and reproducible regimes, is becoming persistently more pressing. To this end, the gas-source molecular beam epitaxy (GS-MBE) growth of GaP/GaAsP/GaP nanowire heterostructures on Si surfaces, according to the vapor-liquid-solid (VLS) mechanism from Au nanoparticles, was studied. Scanning electron microscopy analysis of the as-grown structures showed them to have aspect ratios of approximately 100. Characterization by way of energy dispersive X-ray spectrometry (EDXS) confirmed the core-multishell heterostructure – namely, that a GaAsP layer is radially and axially confined between GaP core and shell layers. Ultra-high resolution transmission electron microscopy indicated that the wires have a wurtzite crystal structure, while atomic layers constituting intermittently appearing stacking faults were observed to be arranged in a zinc-blende structure. Potential for the growth of defect-free nanowires through GS-MBE is proposed, based on the disappearance of stacking faults at growth interruptions. The optical response of single nanowire specimens was investigated through micro-photoluminescence spectroscopy. Emission, attributed to the central GaAsP layer, was observed at roughly 700 nm while sharp spectral features with narrow linewidth, indicative of carrier confinement, were also present. From temperature-dependent photoluminescence and EDXS studies, the phosphorus atomic composition, within the GaAsP segment, was established. Furthermore, it was observed that the luminescence spectrum of a given specimen is dependent upon the structure of the nanowire itself and the position of the excitation spot along the wire length. The foreseeable applications of these nanowires range from macro-electronic light-emitting diodes and photocells to single-photon sources for quantum information technology.
1:00 AM - O7.14
Donor Binding Energies in Rectangular Wurtzite Gallium Nitride / Indium Gallium Nitride Quantum Wires with Spontaneous and Piezoelectric Polarization.
Choudhury Praharaj 1
1 , SanDisk Corporation, Santa Clara, California, United States
Show Abstract1:00 AM - O7.16
Time Evolution of Surface Morphology of GaN Nanorods Grown by HVPE.
Hyeokmin Choe 1 , Sanghwa Lee 1 , Yuri Sohn 1 , Chinkyo Kim 1
1 Physics, Kyunghee University, Seoul Korea (the Republic of)
Show Abstract1:00 AM - O7.17
Scanning X-ray Excited Optical Luminescence Microscopy in Quantum Semiconductor Heterostructures.
Gema Martinez-Criado 1 , Benito Alen 2 , Alejandro Homs 1 , David Fuster 2 , Jose Maria Ripalda 2 , Ana Labrador 1 , Isabelle Letard 1 , Jean Susini 1 , Luisa Gonzalez 2 , Yolanda Gonzalez 2 , Jorge Manuel Garcia 2
1 , ESRF, Grenoble France, 2 , Microelectronics Institute, Madrid Spain
Show Abstract1:00 AM - O7.2
Surface Depletion Effects in Gallium Nitride Nanowires.
Blake Simpkins 1 , Michael Mastro 1 , Charles Eddy 1 , Pehr Pehrsson 1
1 , Naval Research Lab, Washington, District of Columbia, United States
Show AbstractSemiconducting nanowires (NWs) with aspect ratios as high as 1000 are often promoted for use in technologies such as chemical and biological sensors which benefit from high surface to volume ratios. It is well-established that surface-mediated phenomena in these nanoscale elements can dramatically alter their optical,[1] electrical,[2] and mechanical[3] properties. However, effects such as surface-state induced depletion of mobile carriers or enhanced surface recombination can degrade the performance of electrical or optical device elements. These effects increase with decreasing NW radius and can limit the nanowire’s sensitivity to surface charge. Because of the technological relevance of these issues, analytical calculations of surface depletion in cylindrical NWs are carried out by solving Poisson’s equation in cylindrical coordinates. Radial band profiles and carrier distributions are calculated as a function of NW radius and carrier density. It is found that the free carrier population, as measured in a typical gate I-V configuration, resides in a narrow conducting core surrounded by a depleted shell. When carrier concentration values are extracted by dividing this charge over the volume of the NW, carrier concentration is underestimated. This discrepancy reflects the assumption that the experimentally measured carrier population is distributed throughout the entire NW volume when it actually occupies only a narrow conducting core. The size of the conducting core, its relation to NW radius, and the resulting error introduced to carrier density measurements are evaluated, discussed, and compared to experimental results. Gated I-V measurements are used to extract carrier density and mobility for NWs with radii ranging from 15-70 nm. It is found that the measured carrier density decreases with decreasing NW radius and compares very well to an analytical fit accounting for diameter-dependent surface depletion. This measurement artifact is due to the increased depletion depth in smaller wires. The implications of this phenomenon on sensitivity to surface charges will be discussed.[1] A. Shabaev and A.L. Efros, Nano Lett., 4, 1821 (2004).[2] J. Hahm and C.M. Lieber, Nano Lett., 4, 51 (2004).[3] C.-Y. Nam, P. Jaroenapibal, D. Tham, D.E. Luzzi, S. Evoy, and J.E. Fischer, Nano Lett., 6, 153 (2006).
1:00 AM - O7.3
On the Epitaxial Growth of Gallium Nitride Nanorods on Si (111) Surfaces after Controlled Nitridation Procedure by Plasma Assisted Molecular Beam Epitaxy.
Jordi Arbiol 1 2 , Sonia Estrade 2 , Francesca Peiro 2 , Florian Furtmayr 3 , Martin Vielemeyer 3 , Martin Stutzmann 3 , Martin Eickhoff 3 , Joan Ramon Morante 2
1 TEM-MAT, Serveis Cientificotecnics, Universitat de Barcelona, Barcelona, CAT, Spain, 2 EME/CeRMAE/IN2UB, Departament d’Electronica, Universitat de Barcelona, Barcelona, CAT, Spain, 3 Walter Schottky Institut, Technische Universität München, Garching Germany
Show Abstract1:00 AM - O7.5
Optical Antenna Effect in Semiconducting Nanowires.
Jian Wu 1 , Gugang Chen 1 , Qiujie Lu 1 , Humberto Gutierrez 1 , Qihua Xiong 1 , Michael Pellen 3 , Josh Petko 3 , Doug Werner 3 , Peter Eklund 1 2 3
1 Department of Physics, Pennsylvania State University, University Park, Pennsylvania, United States, 3 Department of Electrical Engineering, Pennsylvania State University, University Park, Pennsylvania, United States, 2 Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania, United States
Show Abstract1:00 AM - O7.7
High Spatial Resolution Cathodoluminescence Studies of Single InN and InGaN Nanorods.
D. Khanal 1 2 , D. Ogletree 2 3 , Y. Cui 2 , W. Walukiewicz 2 , E. Calleja 4 , J. Wu 1 2
1 Materials Science and Engineering, University of California Berkeley, Berkeley, California, United States, 2 Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States, 3 Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California, United States, 4 Department of Ingeniería Electrónica-ISOM, Universidad Politécnica, Ciudad Universitaria, Madrid Spain
Show AbstractInN and InGaN are the focus of intense research attention due to their interesting surface properties and widely tunable bandgaps. In particular, InGaN nanowire/nanorod hetero-structures have potentially important applications in solar energy conversion. Vertical arrays of InN and InGaN nanorods were grown on Si(111) substrates using Molecular Beam Epitaxy. We have compared the optical properties of these nanorods and their thin-film counterparts to help understand the role of surface states and their implications for photovoltaic and electrochemical applications. We have performed broad-band and spectroscopic cathodoluminescence (CL) studies of individual InN and InGaN nanorods and ensembles of nanorods using a field-emission Scanning Electron Microscope. The focused electron beam provides a local excitation source with high spatial resolution which helps resolve the origin and annihilation of the luminescence in single nanorods. By varying the incident electron energy, surface and core contributions can be explored. A spatially non-uniform CL signal was detected from individual nanorods and correlated to their composition and geometry. We also observed a strong decay of the CL signal with time, and ascribe this effect to the accumulation of surface charge on the nanorods or population of trap states by the incident electron beam and resultant secondary electrons. This is in contrast to the behavior of thin films which show no decay of luminescence intensity. These results suggest that CL is a powerful, spatially and spectrally resolved tool in probing the material properties of semiconductor nanostructures and heterostructures.
1:00 AM - O7.8
Persistent Photocurrent in InP Nanowires Heteroepitaxially Bridged Between Single Crystal Si Surfaces.
Ataur Sarkar 1 , Sungsoo Yi 2 , M. Saif Islam 1 , Albert Talin 3
1 Electrical and Computer Engineering, University of California, Davis, California, United States, 2 Advanced Laboratories, Philips Lumileds Lighting Company, San Jose, California, United States, 3 , Sandia National Laboratories, Livermore, California, United States
Show AbstractLaterally oriented p-type InP nanowires were grown in a low pressure MOCVD reactor using gold catalyst and bridged between vertically oriented heavily p-doped single crystal silicon electrodes. Photoresponse of a large number of devices with DC bias was characterized with 630 nm He-Ne laser as well as an incoherent white light source. Experimental results demonstrate persistent photoconductivity through a slow decay of excess photocurrent from a maximum measured value of ~1µA with 630 nm He-Ne laser excitation and 2.5 V/µm applied external field. After the light source is shut off, the photogenerated excess carriers recombine very slowly and the excess photocurrent persists for minutes before it decays to the dark current level in the range of ~200 nA. It is observed that persistent photocurrent magnitude varies with bias voltage and wavelength and intensity of the optical illumination. Excess photocurrent decay follows an exponential profile and bias dependent decay rate is observed immediately after the light source is turned off. After a significant interval of time (~10 min) subsequent to the deactivation of the light source, the decay rate is found to be almost bias independent for the external field (2.5 V/µm) used in our experiment. Persistent photocurrent originates from the long recombination time due to several factors, such as carrier trapping in vacancies, defect centers, surface states and built-in potential at the InP/Si interface. All these factors can collectively contribute to trapping of the photogenerated carriers for extended duration and thus exhibit long lasting photocurrent. More work is under way to develop an in-depth understanding of the observed persistent photocurrent in InP nanowires on single crystal Si.
1:00 AM - O7.9
AFM, STM and SPRM Investigations of Multiphase GaN Nanowires and Nanocircuits.
Kaylee McElroy 1 , Benjamin Jacobs 1 , Virginia Ayres 1 , Martin Crimp 1 , Joshua Halpern 2 , MaoQi He 2 , Qian Chen 1 , Yuan Fan 1
1 , Michigan State University, East Lansing, Michigan, United States, 2 , Howard University, Washington D. C., District of Columbia, United States
Show AbstractMultiphase GaN nanowires are novel structures and their physical and electronic properties are still under investigation. The multiphase GaN nanowires in the present experiments were grown using a catalyst free vapor-solid growth mechanism and have both zinc-blende and wurtzite phases throughout the length of the longitudinal axis. Results of atomic force microscopy (AFM), scanning tunneling microscopy (STM) and scanning probe recognition microscopy (SPRM) investigations of dispersed nanowires, nanowire cross-sections fabricated by focused ion beam (FIB) techniques, and nanowire nanoFET circuits are presented. Nanowire nucleation sites are found on hexagonal crystalline wurtzite platelets that form as a matrix prior to nanowire growth. The nucleation sites that resulted in zinc-blende/wurtzite multiphase nanowire growth were identified as nanoscale ledges that form along the sides of the hexagonal platelets. The nanoscale ledges were in the same orientation and coherent with the hexagonal platelets. Using AFM images, each nanoscale ledge was found to be 10-20 atomic layers thick. AFM and STM investigations of single nanowires indicated that the nanowires have triangular cross sections, confirming previously reported high resolution transmission electron microscopy (HRTEM) results. It was further observed from scanning electron microscopy (SEM) investigations that nanowire sides could have active nucleation sites that are microns distant from the initial nucleation site. Thin wurtzite half platelets oriented with three exposed {1010} sides and the (0001) face perpendicular to the growth axis were observed. AFM and STM investigations also indicated possible nucleation sites along the sides of the nanowire.GaN nanowire nanoFET circuits were fabricated by dispersing nanowires from a solution of isopropyl alcohol onto a SiO2 substrate and using conventional electron-beam lithography techniques to pattern Ti-Au contact pads over a nanowire. Scanning probe recognition microscopy (SPRM) was used to investigate electronic properties directly along the nanocircuit. SPRM is a special scanning probe microscope modification developed by our research group in partnership with Veeco Instruments. The scanning probe microscope system itself is given the ability to auto-focus on regions of interest through incorporation of recognition-based tip control. The recognition capability is realized using algorithms and techniques from computer vision, pattern recognition and signal processing fields. Adaptive learning and prediction are also implemented to make detection and recognition procedures quicker and more reliable. The integration of recognition makes the SPRM system more powerful and flexible in investigating specific properties of samples. In the present experiments, scanning probe recognition microscopy (SPRM) was used to investigate variations in the electronic states in the contact region.
Symposium Organizers
Heike Riel IBM Research GmbH
Ted Kamins Hewlett-Packard Laboratories
Hongjin Fan University of Cambridge
Saskia Fischer Ruhr-University of Bochum
Claes Thelander Lund University
O15: Poster Session: II-VI Nanowires and related Materials: Devices and Applications
Session Chairs
Thursday PM, March 27, 2008
Salon Level (Marriott)
9:00 PM - O15.1
Electrical Characterisation of a Low-Density Layer of SnO2-Nanowires Deposited on a Set of Parallel Pt Electrodes.
Ilia Kiselev 1 , Joachim Goschnick *Deceased 1 , Victor Sysoev 2
1 Institut für Mikrostrukturtechnik, Forschungszentrum Karlsruhe, Karlsruhe Germany, 2 , Saratov State Technical University, Saratov Russian Federation
Show Abstract9:00 PM - O15.10
Segmented Chemical Sensor Fabrication Through Templated Electrodeposition.
A. Murray 1 2 , S. Evoy 1 2
1 Devices and Sensors, National Institute for Nanotechnology, Edmonton, Alberta, Canada, 2 Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada
Show Abstract9:00 PM - O15.11
CuInSe2-CdS Core-Shell Nanowires.
Hailin Peng 1 , Chong Xie 1 , David Schoen 1 , Yi Cui 1
1 Department of Materials Science and Engineering, Stanford University, Stanford, California, United States
Show Abstract9:00 PM - O15.12
Probing Exciton Diffusion in Semiconductor Nanorods.
Jinkyoung Yoo 1 , Gyu-Chul Yi 1 , Le Si Dang 2
1 Materials Science and Engineering, POSTECH, Pohang, Gyeongbuk, Korea (the Republic of), 2 Institut Néel, CNRS and Université Joseph Fourier, Grenoble France
Show Abstract9:00 PM - O15.13
Electrical and Luminescent Properties of Doped ZnO Nanowires.
Gennady Panin 1 2 , Andrey Baranov 3 , Oleg Kononenko 2 , Tae Won Kang 1 , Alexander Ilin 2
1 Department of Physics, Dongguk University, QSRC, Seoul Korea (the Republic of), 2 , Institute of Microelectronics Technology, Chernogolovka, Moscow Russian Federation, 3 Department of Chemistry, Moscow State University, Moscow Russian Federation
Show Abstract9:00 PM - O15.14
Polarization Sensitive Devices Based on Randomly Oriented Nanowire Networks.
Yanghai Yu 1 2 , Vladimir Protasenko 2 , Debdeep Jena 3 , Huili Xing 3 , Masaru Kuno 2
1 Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana, United States, 2 Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, United States, 3 Electrical Engineering, University of Notre Dame, Notre Dame, Indiana, United States
Show Abstract9:00 PM - O15.15
Manufacturable In2O3 Nanowire Biosensors on Whole Wafer and Integration with Microfluics System for Selective Functionalization.
Fumiaki Ishikawa 1 , Marco Curreli 1 , Po-Chiang Chen 1 , Mark Thompson 1 , Chongwu Zhou 1
1 , USC, Los Angeles, California, United States
Show Abstract9:00 PM - O15.16
Fabrication and Characterization of CdS/CIS Nanowire Heterojunctions.
Sovannary Phok 1 , Piao Liu 1 , Suresh Rajaputra 1 , Vijay Singh 1
1 electrical & Computer Engineering, University of Kentucky, Lexington, Kentucky, United States
Show Abstract9:00 PM - O15.17
Assembling and Electrical Properties of CdSe Nanowires Devices.
Wei Xu 1 , Hongbin Yu 1 , Nickolaus Smith 2 , Alfred Wooten 2 , Jennifer Hollingsworth 2
1 , Arizona State University, Tempe, Arizona, United States, 2 , Los Alamos National Laboratory, Los Alamos , New Mexico, United States
Show Abstract9:00 PM - O15.18
WO3-x Nanorod Arrays Based Sensors with High Sensitivity and Quick Response for Detecting Pollutants.
Xinpeng Wang 1 , Zhenbo Wang 2 , Xianping Feng 1
1 Physics, University of Puerto Rico, San Juan, Puerto Rico, United States, 2 Applied Chemistry, Harbin Institute of Technology, Harbin, Heilongjiang, China
Show AbstractWe present the new results on the design and the development of sensing materials used for gas sensing application. Tungsten oxide nanorod arrays deposited on the ceramic cylinder have been used for fabrication of a miniaturized two-dimensional sensor. Different size and density of tungsten oxide nanorod arrays were synthesized using chemical vapor deposition techniques. Scanning electron microscope, x-ray diffraction and x-ray photon spectroscopy were used to examine the samples, which indicated that parallel, single crystalline, nonstoichiometric tungsten oxide nanorod arrays were already fabricated. The sensibility and capacity towards methane and acetone at different temperatures were tested. The results revealed that the new sensor was highly sensitive to methane down to 10 ppm but poorly sensitive to acetone up to 1600 ppm, which showed the promising selectivity of mixture of organic pollutant gases based on different their sensitivities. Further studies exhibited that the saturated concentration of methane linearly increased with decreasing the temperature; the sensitivity enhanced by decreasing operating temperature as well. Moreover, different responding and recovering behaviors of the sensor towards pollutant gas input durations were measured at room temperature (20 oC). With 4 ms input, comparable response time (3 ms), responding duration (6ms) and recovery time (4 ms) were obtained, which demonstrated the possibility of sensing application of the WO3-x nanorod arrays based sensor under pollutant gas exposure of ultrashort duration or trace quantity.
9:00 PM - O15.19
Novel Fabrication of SnO2 Nanowire Gas Sensor with a High Sensitivity.
Kyoung Jin Choi 1 , Young-Jin Choi 1 , In-Sung Hwang 1 , Dong-Wan Kim 1 , Jae-Gwan Park 1 , Jae-Hwan Park 2 , Jong-Heun Lee 3
1 Nano-Materials Research Center, Korea Institute of Science and Technology (KIST), Seoul Korea (the Republic of), 2 Department of Electronic Engineering, Chungju National University, Chungju Korea (the Republic of), 3 Department of Materials Science and Engineering, Korea University, Seoul Korea (the Republic of)
Show Abstract9:00 PM - O15.20
Single ZnO Nanowire Logic Gates on Flexible Plastic Substrate.
Jeongmin Kang 1 , Dong-Young Jeong 1 , Changjun Yun 1 , Donghyuk Yeom 1 , Jamin Koo 1 , Sangsig Kim 1
1 Electrical Engineering , Korea University, Seoul Korea (the Republic of)
Show AbstractIn this study, an inverter (NOT logic gate) was built with two top-gate field effect transistors (FETs) fabricated on a single ZnO nanowire dispersed on a polyether sulfone (PES) flexible plastic substrates and its electrical characteristics were investigated. Two top-gate ZnO nanowire-based FETs used in the inverter exhibit peak transconductances of 211 and 201 nS, field effect mobilities of 18.7 and 17.7cm2/V-1s-1, and Ion/Ioff ratios of about 104. When the PES substrate was bent under a strain of 0.8 %, the voltage gain of inverter was slightly changed from 0.85 to 0.82. Furthermore, a NAND logic gate device was built with three top-gate FETs fabricated on a single ZnO nanowire, and its operation characteristics corresponded to the truthtables
9:00 PM - O15.21
Effects of Post-plasma Treatment on Electrical Properties of ZnO Nanowires.
Kwang Sung Choi 1 , Hyun-Wook Ra 1 , Yeon Ho Im 1
1 , Chonbuk National University, Jeonju, Jeonbuk, Korea (the Republic of)
Show Abstract9:00 PM - O15.22
Gas Sensing with ZnO Nnanowires Fabricated by Bottom-up and Top-down Approaches.
Hyun-Wook Ra 1 , Kwang Sung Choi 1 , Yeon Ho Im 1
1 , Chonbuk National University, Jeonju, Jeonbuk, Korea (the Republic of)
Show Abstract9:00 PM - O15.23
Nanowire Solar Cell Sensitized with II-VI Quantum Dots.
Athavan Nadarajah 1 , Robert Word 1 , Rolf Koenenkamp 1
1 Physics, Portland State University, Portland, Oregon, United States
Show Abstract9:00 PM - O15.24
Semiconductor Nanowires and Branched Nanowires as Solar Cell Materials
Jia Zhu 1 , Lifeng Cui 1 , Hailin Peng 1 , Stephen Connor 1 , Yi Cui 1
1 , Stanford University, Stanford, California, United States
Show AbstractNanowires and their branched structures offer new types of materials for solar energy conversion due to their large surface area and efficient electron transport. Here we report PbSe hyperbranched nanowire network through vapor-liquid-solid growth. The branches within a hyperbranched network show unprecedented regular order compared to previous studies. The hyperbranched networks can be grown epitaxially on NaCl substrates, a low cost substrate for device array fabrication. Electrical measurements across branched NWs reveal the evolution of charge carrier transport with distance and degree of branching. In addition, we will also discuss our recent core-shell semiconductor nanowire structures for solar cell application.
9:00 PM - O15.25
Multisegment Nanowires Sensors for Biomolecules Detection.
Xu Wang 1 , Joshua Knapp 2 , Peter Atkinson 2 , Cengiz Ozkan 3
1 Chemical Engineering, University of California, Riverside, Riverside, California, United States, 2 Biochemistry, University of California, Riverside, Riverside, California, United States, 3 Mechanical Engineering, University of California, Riverside, Riverside, California, United States
Show Abstract9:00 PM - O15.3
Electrical and Mechanical Characterization of Au-CdSe-Au Heterostructured Nanowires.
Kwan Skinner 1 , Chris Dwyer 4 , Russell Taylor 2 , Sean Washburn 1 2 3
1 Curriculum in Applied and Materials Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States, 4 Department of Electrical & Computer Engineering, Duke University, Durham, North Carolina, United States, 2 Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States, 3 Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
Show AbstractIn recent years, much attention has been devoted to the electrical characterization of quasi-1d semiconductor nanostructures including nanowires and CNTs. Template derived heterostructured nanowires fabricated through electrochemistry are of particular interest due the ability to define the metal-semiconductor contacts of these structures in situ. We present our findings of the electrical characteristics of heterostructured Au-CdSe-Au nanowires. In addition, we also report on the mechanical properties of the junctions of these heterostructured nanowires, which we extract from force-strain curves obtained on suspended structures with an atomic force microscope through lateral force manipulations, as the electrical properties of these structures are largely defined by the junction itself.
9:00 PM - O15.4
Room Temperature UV Laser Emission from Ferromagnetic Zn1-xFexO Nanoneedles.
Huiying Yang 1 , Shu Ping Lau 1 , Tun Seng Herng 1 , Siu Fung Yu 1 , Tanemura Masaki 2
1 Electrical & Electronics Engineering, Nanyang Technological University, Singapore Singapore, 2 Department of Environmental Technology, Nagoya Institute of Technology, Nagoya Japan
Show AbstractZn1-xFexO nanoneedles were fabricated from their thin film counterparts on silicon substrates by an Ar+ ion sputtering technique. To achieve metal doping, Fe2+ was deposited during Ar+ ion irradiation using the arc plasma gun operated in pulse modes from 0.2 to 1.0 Hz. The saturated magnetization moment was measured from 0.307 emu/cm3 to 0.659 emu/cm3 at the field of 10 kOe with various Fe concentrations. Significantly, Zn1-xFexO nanoneedles also exhibit ultraviolet (UV) random lasing emission at room temperature, which indicates that they may have important potential applications in magneto-optic and magneto-electronic nanodevices.
9:00 PM - O15.5
Quantifying Oxygen Diffusion in ZnO Nanodevice.
Jin Liu 1 , Puxian Gao 2 , Wenjie Mai 1 , Changshi Lao 1 , Rao Tummala 1 , Zhong Wang 1
1 , Georgia Institute of Technology, Atlanta, Georgia, United States, 2 Chemical, Materials and Biomolecular Engineering, University of Connecticut, Storrs, Connecticut, United States
Show AbstractZnO is an important material as resonators for Micro-Electro-Mechanical Systems (MEMS), optical material for fabricating blue Light Emitting Diodes (LEDs), piezoelectric and semiconducting material for actuators. Field Effect Transistor (FET), gas sensor and PH meter using ZnO nanowire/nanobelts have been reported, the performance of which strongly relies on the oxygen deficiency and distribution in ZnO nanostructures. The conductivity of ZnO can be tuned by changing the oxygen deficiency or vacancies. Controlling oxygen diffusion and distribution in ZnO is important for understanding its electronic and optical properties. In this paper, a new method is presented for quantifying oxygen diffusion behavior in a nanodevice fabricated using individual ZnO nanowire/nanobelt.[1] A nanodevice was first built using a single nanobelt. Defects are introduced into nanobelt during specific nanofabrication procedure. Then, after the device being exposed to atomosphere for several days, oxygen in air diffused into the nanobelt and significantly changed the conductivity of the device. By comprising the experimentally measured conductivity and that of simulated result, the diffusion coefficient of oxygen in ZnO nanowires/nanobelts has been derived. This study will be helpful for predicting the stability of the devices made using ZnO nanowire/nanobelt.1. Liu, J., P. Gao, W. Mai, et al., Quantifying Oxygen Diffusion in Zno Nanobelt. Applied Physics Letters, 2006. 89(6): p. 063125-3.
9:00 PM - O15.7
Ab Initio Study of the Electronic Structure of Core-Shell Nanorods.
Thomas Sadowski 1 , Rampi Ramprasad 1
1 , University of Connecticut, Seymour, Connecticut, United States
Show Abstract9:00 PM - O15.8
Electrical Characteristics of the Passivated ZnO and SnO2 Field Effect Transistors.
Dong Wook Kim 1 , Hyun Jin Ji 1 , Soo Han Choi 1 2 , Young Seung Cho 1 2 , Gyu Tae Kim 1
1 Electrical Engineering, Korea University, Seoul Korea (the Republic of), 2 Semiconductor R&D center, Samsung Electronics, Hwasung-City Korea (the Republic of)
Show Abstract9:00 PM - O15:2-6Devices
O15.9 Transferred to O17.7
Show Abstract
Symposium Organizers
Heike Riel IBM Research GmbH
Ted Kamins Hewlett-Packard Laboratories
Hongjin Fan University of Cambridge
Saskia Fischer Ruhr-University of Bochum
Claes Thelander Lund University
O17: ZnO and Related Materials
Session Chairs
Friday AM, March 28, 2008
Room 2004 (Moscone West)
9:45 AM - **O17.1
From Ordered Arrays of Nanowires to Controlled Solid State Reactions.
Margit Zacharias 1 2
1 IMTEK, University of Feiburg, Freiburg Germany, 2 , MPI of Microstructure Physics, Halle Germany
Show Abstract10:15 AM - O17.2
Extraction of the Electrical Parameters of Individual Metal Oxide Nanowires using Two-point Probing to FIB-fabricated Platinum Electrodes.
Juan Daniel Prades 1 , Roman Jimenez-Diaz 1 , Francisco Hernandez-Ramirez 2 1 , Sven Barth 3 4 , Olga Casals 1 , Alberto Tarancon 1 , Teresa Andreu 1 , Miguel Angel Juli 2 1 , Albert Cirera 1 , Albert Cornet 1 , Alejandro Perez-Rodriguez 2 , Sanjay Mathur 3 4 , Albert Romano-Rodriguez 1 , Juan Ramon Morante 1
1 EME and IN2UB, Department of Electronics, University of Barcelona, Barcelona Spain, 2 , NTEC106, S.L., L'Hospitalet de Llobregat Spain, 3 Department of Chemistry, Wuerzburg University, Wuerzburg Germany, 4 Department of Nanocrystalline Materials and Thin Film Systems, Leibniz Institute of New Materials, Saarbruecken Germany
Show Abstract10:30 AM - O17.3
Inorganic Nanowires for Flexible Electrical and Optical Devices.
Athavan Nadarajah 1 , Jan Meiss 1 , Robert Word 1 , Rolf Koenenkamp 1
1 Physics, Portland State University, Portland, Oregon, United States
Show Abstract10:45 AM - O17.4
Gallium Oxide Waveguiding Nanowires Doped with Luminescent Ions.
Emilio Nogales 1 , Bianchi Mendez 1 , Javier Piqueras 1 , Jose Angel Garcia 2 , Katharina Lorenz 3 , Eduardo Alves 3
1 Dpto. de Física de Materiales, Universidad Complutense de Madrid, Madrid Spain, 2 Dpt. de Física Aplicada II, Universidad del País Vasco, Bilbao Spain, 3 , Instituto Tecnológico e Nuclear, Sacavém Portugal
Show Abstract11:30 AM - O17.5
Nanomanipulation Techniques of Semiconductor Nanowires for Material Property Characterisation and Device Prototyping.
Samuel Hoffmann 1 , Christophe Ballif 2 , Johann Michler 1 , Silke Christiansen 1
1 Materials- and Nanomechanics Laboratory, EMPA, Swiss Federal Laboratories for Materials Testing and Research, Thun Switzerland, 2 Institute of Microtechnology, University of Neuchâtel, Neuchâtel Switzerland
Show Abstract11:45 AM - O17.6
Megahertz Frequency Operation of Nanowire-Based Transparent TFT Devices.
Eric Dattoli 1 , Wei Lu 1
1 Electrical Engineering & Computer Science, University of Michigan, Ann Arbor, Michigan, United States
Show Abstract12:00 PM - O17.7
Controlling the Alignment of V2O5 Nanowires in Printing-based Patterning and the Effect of Alignment on the Electrical Stability of Nano-devices.
Yong-Kwan Kim 1 , Dae Il Kim 1 , Gunchul Shin 1 , Jaehyun Park 1 , Jeong Sook Ha 1 , Pil-Soo Kang 2 , Hye Yeon Ryoo 2 , Gyu Tae Kim 2
1 Department of Chemical and Biological Engineering, Korea University , Seoul Korea (the Republic of), 2 School of Electrical Engineering, Korea University, Seoul Korea (the Republic of)
Show AbstractFriday, March 28Transferred Poster O15.9 to O17.7 @ 11:00 AMControlling the Alignment of V2O5 Nanowires in Printing-based Patterning and the Effect of Alignment on the Electrical Stability of Nano-devices. Yong-Kwan Kim
12:15 PM - O17.8
Low Frequency Noise of ZnO Nanowire with Contact Resistance and Different Channel Width.
Choi Soo Han 1 2 , Kim Gyu Tae 1
1 Electrical Engineering , Korea University, Seuol Korea (the Republic of), 2 Semiconductor R&D Center, Samsung Electronics, HwaSung-City Korea (the Republic of)
Show Abstract12:30 PM - O17.9
Tunable Electrical and Optical characteristics of Surface Architecture-Controlled ZnO Nanowires.
Woong-Ki Hong 1 , Jung Inn Sohn 2 , Dae-Kue Hwang 1 , Soon-Shin Kwon 1 , Gunho Jo 1 , Sunghoon Song 1 , Seong-Ju Park 1 , Mark Welland 2 , Takhee Lee 1
1 , Gwangju Institute of Science and Technology, Gwangju Korea (the Republic of), 2 , Nanoscience centre, University of Cambridge, Cambridge United Kingdom
Show Abstract12:45 PM - O17.10
High Frequency Impedance Measurements of ZnO Nanorod Arrays.
David Scrymgeour 1 , Clark Highstrete 1 , Yun-Ju Lee 1 , Erik Spoerke 1 , Mark Lee 1 , Julia Hsu 1
1 , Sandia National Laboratories, Albuquerque, New Mexico, United States
Show Abstract