Relationship between planar GaAs nanowire growth direction and substrate orientation

Dowdy, Ryan; Walko, Donald A.; Li, Xiuling

doi:10.1088/0957-4484/24/3/035304

Cited by 35 publications

(46 citation statements)

References 20 publications

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“…Thus, ± is the bi-direction we assign to our nanotracks. This directional assignment agrees well with other reports of self-aligned planar growths63646566. Figure 5(c) shows how lateral motion in the ± directions is achieved by this process; the formation of a flexible liquid surface at the liquid-solid interface facilitates preferential growth away from the c -axis, with the droplet motion restricted in-plane.…”

Section: Resultssupporting

confidence: 90%

Surface effects of vapour-liquid-solid driven Bi surface droplets formed during molecular-beam-epitaxy of GaAsBi

Steele

Lewis

Horvat

et al. 2016

Sci Rep

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Herein we investigate a (001)-oriented GaAs1−xBix/GaAs structure possessing Bi surface droplets capable of catalysing the formation of nanostructures during Bi-rich growth, through the vapour-liquid-solid mechanism. Specifically, self-aligned “nanotracks” are found to exist trailing the Bi droplets on the sample surface. Through cross-sectional high-resolution transmission electron microscopy the nanotracks are revealed to in fact be elevated above surface by the formation of a subsurface planar nanowire, a structure initiated mid-way through the molecular-beam-epitaxy growth and embedded into the epilayer, via epitaxial overgrowth. Electron microscopy studies also yield the morphological, structural, and chemical properties of the nanostructures. Through a combination of Bi determination methods the compositional profile of the film is shown to be graded and inhomogeneous. Furthermore, the coherent and pure zincblende phase property of the film is detailed. Optical characterisation of features on the sample surface is carried out using polarised micro-Raman and micro-photoluminescence spectroscopies. The important light producing properties of the surface nanostructures are investigated through pump intensity-dependent micro-PL measurements, whereby relatively large local inhomogeneities are revealed to exist on the epitaxial surface for important optical parameters. We conclude that such surface effects must be considered when designing and fabricating optical devices based on GaAsBi alloys.

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Section: Resultssupporting

confidence: 90%

Surface effects of vapour-liquid-solid driven Bi surface droplets formed during molecular-beam-epitaxy of GaAsBi

Steele

Lewis

Horvat

et al. 2016

Sci Rep

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“…This bi-directional growth facet agrees well with the literature. 25,30,31,36 That we see equal movement in opposite directions eliminates thermal gradient or electric field effects underpinning this preference. The typical details of the nanotrack morphology are contained in the AFM data shown in Fig.…”

Section: Morphological Characterization Of In-plane Gaasbi Nanotracksmentioning

confidence: 63%

Mechanism of periodic height variations along self-aligned VLS-grown planar nanostructures

et al. 2015

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In this study we report in-plane nanotracks produced by molecular-beam-epitaxy (MBE) exhibiting lateral self-assembly and unusual periodic and out-of-phase height variations across their growth axes. The nanotracks are synthesized using bismuth segregation on the GaAsBi epitaxial surface, which results in metallic liquid droplets capable of catalyzing GaAsBi nanotrack growth via the vapor-liquid-solid (VLS) mechanism. A detailed examination of the nanotrack morphologies is carried out employing a combination of scanning electron and atomic force microscopy and, based on the findings, a geometric model of nanotrack growth during MBE is developed. Our results indicate diffusion and shadowing effects play significant roles in defining the interesting nanotrack shape. The unique periodicity of our lateral nanotracks originates from a rotating nucleation "hot spot" at the edge of the liquid-solid interface, a feature caused by the relative periodic circling of the non-normal ion beam flux incident on the sample surface, inside the MBE chamber. We point out that such a concept is divergent from current models of crawling mode growth kinetics and conclude that these effects may be utilized in the design and assembly of planar nanostructures with controlled nonmonotonous structure In this study we report in-plane nanotracks produced by molecular-beam-epitaxy (MBE) exhibiting lateral self-assembly and unusual periodic and out-of-phase height variations across their growth axes. The nanotracks are synthesized using bismuth segregation on the GaAsBi epitaxial surface, which results in metallic liquid droplets capable of catalyzing GaAsBi nanotrack growth via the vapor-liquid-solid (VLS) mechanism. A detailed examination of the nanotrack morphologies is carried out employing a combination of scanning electron and atomic force microscopy and, based on the findings, a geometric model of nanotrack growth during MBE is developed. Our results indicate diffusion and shadowing effects play significant roles in defining the interesting nanotrack shape. The unique periodicity of our lateral nanotracks originates from a rotating nucleation "hot spot" at the edge of the liquid-solid interface, a feature caused by the relative periodic circling of the non-normal ion beam flux incident on the sample surface, inside the MBE chamber. We point out that such a concept is divergent from current models of crawling mode growth kinetics and conclude that these effects may be utilized in the design and assembly of planar nanostructures with controlled non-monotonous structure.

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“…Reproduced with permission from Refs[128,129]. The GaAs planar nanowires grow exactly along the two nonparallel surface projections (blue and red labels) of the two equivalent <111> B directions.…”

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confidence: 99%

Vapor-Liquid-Solid Growth of Semiconductor Nanowires

Redwing

Miao

2015

Handbook of Crystal Growth

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Relationship between planar GaAs nanowire growth direction and substrate orientation

Cited by 35 publications

References 20 publications

Surface effects of vapour-liquid-solid driven Bi surface droplets formed during molecular-beam-epitaxy of GaAsBi

Surface effects of vapour-liquid-solid driven Bi surface droplets formed during molecular-beam-epitaxy of GaAsBi

Mechanism of periodic height variations along self-aligned VLS-grown planar nanostructures

Vapor-Liquid-Solid Growth of Semiconductor Nanowires

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