期刊
NANO LETTERS
卷 14, 期 7, 页码 3938-3944出版社
AMER CHEMICAL SOC
DOI: 10.1021/nl501239h
关键词
Nanowire; GaAs; HVPE; VLS; crystal structure; chemical potential
类别
资金
- FP7 project NANOEMBRACE [316751]
- FP7 project FUNPROB [269169]
- Russian Foundation for Basic Research
- Region Auvergne
- European FEDER
We report the Au catalyst-assisted synthesis of 20 mu m long GaAs nanowires by the vapor-liquid-solid hydride vapor phase epitaxy (HYPE) exhibiting a polytypism-free zincblende phase for record radii lower than 15 nm down to 5 nm. HVPE makes use of GaCl gaseous growth precursors at high mass input of which fast dechlorination at the usual process temperature of 715 degrees C results in high planar growth rate (standard 30-40 mu m/h). When it comes to the vapor-liquid-solid growth of nanowires, fast solidification at a rate higher than 100 mu m/h is observed. Nanowire growth by HYPE only proceeds by introduction of precursors in the catalyst droplets from the vapor phase. This promotes almost pure axial growth leading to nanowires with a constant cylinder shape over unusual length. The question of the cubic zincblende structure observed in HYPE-grown GaAs nanowires regardless of their radius is at the heart of the paper. We demonstrate that the vapor-liquid-solid growth in our conditions takes place at high liquid chemical potential that originates from very high influxes of both As and Ga. This yields a Ga concentration systematically higher than 0.62 in the Au-Ga-As droplets. The high Ga concentration decreases the surface energy of the droplets, which disables nucleation at the triple phase line thus preventing the formation of wurtzite structure whatever the nanowire radius is.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据