3D Atomic‐Scale Insights into Anisotropic Core–Shell‐Structured InGaAs Nanowires Grown by Metal–Organic Chemical Vapor Deposition. Issue 31 (19th June 2017)

• Record Type: Journal Article
• Authors: Qu, Jiangtao; Du, Sichao; Burgess, Tim; Wang, Changhong; Cui, Xiangyuan; Gao, Qiang; Wang, Weichao; Tan, Hark Hoe; Liu, Hui; Jagadish, Chennupati; Zhang, Yingjie; Chen, Hansheng; Khan, Mansoor; Ringer, Simon; Zheng, Rongkun
• Is Part Of: Advanced materials. Volume 29:Issue 31(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-06-19
• Subjects: atom probe tomography -- core–shell structures -- epitaxy growth -- gold catalysts -- InGaAs nanowires; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.201701888
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract : III–V ternary InGaAs nanowires have great potential for electronic and optoelectronic device applications; however, the 3D structure and chemistry at the atomic‐scale inside the nanowires remain unclear, which hinders tailoring the nanowires for specific applications. Here, atom probe tomography is used in conjunction with a first‐principles simulation to investigate the 3D structure and chemistry of InGaAs nanowires, and reveals i) the nanowires form a spontaneous core–shell structure with a Ga‐enriched core and an In‐enriched shell, due to different growth mechanisms in the axial and lateral directions; ii) the shape of the core evolves from hexagon into Reuleaux triangle and grows larger, which results from In outward and Ga inward interdiffusion occurring at the core–shell interface; and iii) the irregular hexagonal shell manifests an anisotropic growth rate on {112}A and {112}B facets. Accordingly, a model in terms of the core–shell shape and chemistry evolution is proposed, which provides fresh insights into the growth of these nanowires. Abstract : Spontaneous core–shell InGaAs nanowires are grown by metal–organic chemical vapor deposition and investigated with atom probe tomography, transmission electron microscopy, and density functional theory. The results reveal that a Ga‐rich core coarsens from hexagonal to triangular due to species uphill interdiffusion, and an In‐rich shell is owing to a surface catalyst effect, interdiffusion, and low formation energy. A hexagonal‐shaped shell results from anisotropic growth on a {112}A and B facet.