Manipulated Growth of GaAs Nanowires: Controllable Crystal Quality and Growth Orientations via a Supersaturation-Controlled Engineering Process

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• 作者：Ning Han ; Fengyun Wang ; Jared J. Hou ; SenPo Yip ; Hao Lin ; Ming Fang ; Fei Xiu ; Xiaoling Shi ; TakFu Hung ; Johnny C. Ho
• 刊名：Crystal Growth & Design
• 出版年：2012
• 出版时间：December 5, 2012
• 年：2012
• 卷：12
• 期：12
• 页码：6243-6249
• 全文大小：489K
• 年卷期：v.12,no.12(December 5, 2012)
• ISSN：1528-7505

文摘

Controlling the crystal quality and growth orientation of high performance III鈥揤 compound semiconductor nanowires (NWs) in a large-scale synthesis is still challenging, which could restrict the implementation of nanowires for practical applications. Here we present a facile approach to control the crystal structure, defects, orientation, growth rate and density of GaAs NWs via a supersaturation-controlled engineering process by tailoring the chemical composition and dimension of starting Au_xGa_y catalysts. For the high Ga supersaturation (catalyst diameter < 40 nm), NWs can be manipulated to grow unidirectionally along 111 with the pure zinc blende phase with a high growth rate, density and minimal amount of defect concentration utilizing the low-melting-point catalytic alloys (AuGa, Au₂Ga, and Au₇Ga₃ with Ga atomic concentration > 30%), whereas for the low Ga supersaturation (catalyst diameter > 40 nm), NWs are grown inevitably with a mixed crystal orientation and high concentration of defects from high-melting-point alloys (Au₇Ga₂ with Ga atomic concentration < 30%). In addition to the complicated control of processing parameters, the ability to tune the composition of catalytic alloys by tailoring the starting Au film thickness demonstrates a versatile approach to control the crystal quality and orientation for the uniform NW growth.