Palladium Catalyzed Defect-free <110> Zinc-Blende Structured InAs Nanowires
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Palladium Catalyzed Defect-free Zinc-Blende Structured InAs Nanowires
Hongyi Xu1, Qiang Gao2, H. Hoe Tan2, Chennupati Jagadish2 and Jin Zou1,3 1
Materials Engineering, The University of Queensland, QLD 4072, Australia
2
Department of Electronic Materials Engineering, Research School of Physics and Engineering,
The Australian National University, Canberra, ACT 0200, Australia 3
Centre for Microscopy and Microanalysis, The University of Queensland, QLD 4072, Australia
ABSTRACT In this study, Pd thin film is used as catalyst to grow epitaxial InAs nanowires on GaAs(111)B substrate in a metal-organic chemical vapor deposition reactor to explore the growth mechanism and the effects of non-gold catalysts in the growth of III-V epitaxial nanowires. Through detailed morphological, structural and chemical characterization using scanning and transmission electron microscopy, it is found that defect-free zinc-blende structured epitaxial InAs nanowires are grown along the directions with four {111} sidewall facets forming a diamond shaped cross-section. Furthermore, the interface between the nanowire/catalyst is found to be the uncommon {113} planes. It is anticipated that these zinc-blende structured InAs nanowires are grown via the vapor-liquid-solid mechanism. The defect-free nature of these nanowires arises from the non- growth direction and non-{111} nanowire/catalyst interface. INTRODUCTION III-V semiconductor nanowires have shown superior electrical, electronic and optoelectronic properties, which turned them into popular candidates of advanced building blocks for future nanodevices [1]. As a consequence, theoretical and experimental research on epitaxial III-V semiconductor nanowires has been expanded rapidly over the recent years. Tremendous efforts have been devoted to improving the control of the morphological and structural properties of III-V nanowires by tuning the key growth parameters, namely the growth temperature and V/III ratio [2,3]. In the growth of these epitaxial nanowires, Au catalysts [4,5] have been widely used in both molecular beam epitaxy and metal-organic chemical vapor deposition (MOCVD) systems, benefited from its chemical inertness and ability to form lowtemperature eutectic alloys with various group III elements. In contrast, less attention has been paid to controlling the growth of epitaxial III-V nanowires by using non-Au catalysts [6]. In this study, using a thin palladium film as catalyst, we demonstrate the epitaxial growth of InAs nanowires on GaAs{111}B substrates using MOCVD. Detailed electron microscopy investigations indicate that the defect-free zinc-blende structured InAs nanowires are grown directions with four low-energy {111} faceted sidewalls and along the
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nanowire/catalyst interfaces, while the post-growth catalysts are body-centered-cubic structured InPd single crystal. This study suggests that, by altering the nanowire growth to non- directions and the nanowire/catalyst interface to non-{111} planes, defect-free zinc-blende structured nanowires may be realized. E
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