|AVS 58th Annual International Symposium and Exhibition|
|Nanometer-scale Science and Technology Division||Tuesday Sessions|
|Session:||Nanowires and Nanoparticles II: Characterization and Synthesis|
|Presenter:||C. Ngo, University of California Los Angeles|
|Authors:||C. Ngo, University of California Los Angeles
M. Pozuelo, University of California Los Angeles
M. Mecklenburg, University of California Los Angeles
H. Zhou, University of California Los Angeles
B.C. Regan, University of California Los Angeles
R.F. Hicks, University of California Los Angeles
S. Kodambaka, University of California Los Angeles
|Correspondent:||Click to Email|
Group III–V semiconductors possess high carrier mobilities and small band gaps, making them applicable to nanoelectronics and optoelectronics. Properties of these materials can in principle be controllably tuned by the fabrication of low-dimensional structures, such as nanowires. Nanowires are most commonly grown via the vapor-liquid-solid (VLS) process using Au as the catalyst. A variant of this approach is the self-catalyzed VLS process, where one of the elements of the growing material promotes the one-dimensional growth can also yield nanowires. Recent studies show that InP and InP1-xSbx nanostructures can be grown via metalorganic chemical vapor deposition (MOCVD) using indium and indium-antimonide droplets as catalysts. In this talk, we present results from studies focused on understanding the influence of metalorganic precursor flow rates on the compositional and structural evolution of InP1-xSbx alloy nanowires.
All of our samples are grown via MOCVD using trimethylindium (TMIn), tertiarybutylphosphine (TBP), and trimethylantimonide (TMSb) as precursors, with liquid indium droplets as the catalysts and InP(111)B as substrates. The as-grown structures are characterized using scanning and transmission electron microscopies, selected area electron diffraction, energy dispersive x-ray spectroscopy, and scanning TEM to determine their morphology, crystallinity, and composition.
We demonstrate the successful growth of InP1-xSbx alloy nanostructures of desired Sb content that is tunable with substrate temperature and TMSb flow rate. Interestingly, doubling the precursor flow rates, at a given temperature, leads to crystallization of pure wurtzite-structured InSb at the catalyst-wire interface. We attribute this phenomenon to the precipitation of excess Sb present in the indium droplets during InP1-xSbx alloy growth. By taking advantage of the differences in growth kinetics of InP and InSb, we demonstrate the formation of compositionally-abrupt interfaces in InP/InSb axial nanowire heterostructures.
 M. Pozuelo, S.V. Prikhodko, R. Grantab, H. Zhou, L. Gao, S.D. Sitzman, V. Gambin, V.B. Shenoy, R.F. Hicks, and S. Kodambaka, “Zincblende to Wurtzite Transition During the Self-catalyzed Growth of InP Nanostructures” J. Crystal Growth 312, 2305 (2010).
 H. Zhou, M. Pozuelo, R.F. Hicks, and S.Kodambaka, “Self-catalyzed vapor-liquid-solid growth of InP1-xSbx nanostructures” J. Crystal Growth 319, 25 (2011).