Understanding the True Shape of Au-Catalyzed GaAs Nanowires
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- 作者：Nian Jiang ; Jennifer Wong-Leung ; Hannah J. Joyce ; Qiang Gao ; Hark Hoe Tan ; Chennupati Jagadish
- 刊名：Nano Letters
- 出版年：2014
- 出版时间：October 8, 2014
- 年：2014
- 卷：14
- 期：10
- 页码：5865-5872
- 全文大小：379K
- ISSN：1530-6992
文摘
With increasing interest in nanowire-based devices, a thorough understanding of the nanowire shape is required to gain tight control of the quality of nanowire heterostructures and improve the performance of related devices. We present a systematic study of the sidewalls of Au-catalyzed GaAs nanowires by investigating the faceting process from the beginning with vapor鈥搇iquid鈥搒olid (VLS) nucleation, followed by the simultaneous radial growth on the sidewalls, and to the end with sidewall transformation during annealing. The VLS nucleation interface of our GaAs nanowires is revealed by examining cross sections of the nanowire, where the nanowire exhibits a Reuleaux triangular shape with three curved surfaces along {112}A. These curved surfaces are not thermodynamically stable and adopt {112}A facets during radial growth. We observe clear differences in radial growth rate between the 鉄?12鉄〢 and 鉄?12鉄〣 directions with {112}B facets forming due to the slower radial growth rate along 鉄?12鉄〣 directions. These sidewalls transform to {110} facets after high temperature (>500 掳C) annealing. A nucleation model is proposed to explain the origin of the Reuleaux triangular shape of the nanowires, and the sidewall evolution is explained by surface kinetic and thermodynamic limitations.