Simulating Vapor-Liquid-Solid Growth of Au-Seeded InGaAs Nanowires.

Erik K Mårtensson,Jonas Johansson,Kimberly A Dick

doi:10.1021/acsnanoscienceau.1c00052

Erik K Mårtensson, Jonas Johansson + Show 1 more

Open Access

https://doi.org/10.1021/acsnanoscienceau.1c00052

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Journal: ACS nanoscience Au	Publication Date: Feb 7, 2022
Citations: 7	License type: CC BY 4.0

Affiliation: Lund University

Abstract

Ternary III-V nanowires are commonly grown using the Au-seeded vapor-liquid-solid method, wherein the solid nanowires are grown from nanoscale liquid seed particles, which are supplied with growth species from the surrounding vapor phase. A result of the small size of these seed particles is that their composition can vary significantly during the cyclical layer-by-layer growth, despite experiencing a constant pressure of growth species from the surrounding vapor phase. Variations in the seed particle composition can greatly affect the solid nanowire composition, and these cyclical dynamics are poorly understood for ternary nanowire growth. Here, we present a method for simulating nanowire growth which captures the complex cyclical dynamics using a kinetic Monte Carlo framework. In the framework, a nanowire grows through the attachment or detachment of one III-V pair at the time, with rates that are based on the momentary composition of the seed particle. The composition of the seed evolves through the attachment and detachment of III-V pairs to the solid nanowire and through the impingement or evaporation of single atoms to the surrounding vapor. Here, we implement this framework using the As-Au-Ga-In materials system and use it to simulate the growth of Au-seeded InGaAs nanowires with an average solid Ga/III ratio around 0.5. The results show that nucleation preferentially occurs via clusters of InAs and that the compositional hierarchy of the liquid seed (X As < X Ga < X In) determines much of the dynamics of the system. We see that imposing a constraint on the simulation, that only the most recently attached III-V pair can be detached, resulted in a significant narrowing of the compositional profile of the nanowire. In addition, our results suggest that, for ternary systems where the two binaries are heavily mismatched, the dynamics of the seed particle may result in an oscillating compositional profile.

Highlights

Multicomponent III−V materials in the form of nanowires offer some unique benefits: The nanowire shape enables the lateral relaxation of strain, meaning that nanowire heterostructures of highly mismatched III−V materials can be formed without the formation of defects along the interface which would occur for planar growth of the same heterostructure.[1]
It is well established that the nanowire growth typically occurs in a cyclical layer-by-layer fashion, with repeating periods of incubation, depletion, and layer propagation.[7,8]
We assume that the system can change via 1 of 12 possible events; there are 4 possible atoms which can condense onto the seed particle, 4 possible atoms which can evaporate from the particle, 2 possible III−V pairs which can be removed from the seed and attach to the solid nanowire, or 2 possible III−V pairs which can be added to the seed after detaching from the nanowire

Summary

Introduction

Multicomponent III−V materials in the form of nanowires offer some unique benefits: The nanowire shape enables the lateral relaxation of strain, meaning that nanowire heterostructures of highly mismatched III−V materials can be formed without the formation of defects along the interface which would occur for planar growth of the same heterostructure.[1]. Nanowires are commonly grown using the vapor−liquid−. There, the solid nanowire grows from a liquid seed particle. The diameter of the seed particle is typically in the order of tens of nanometers, and the most well used material for the seed particle is Au which alloys with the growth species. The seed particle is continuously supplied with growth species from a surrounding vapor phase. It is well established that the nanowire growth typically occurs in a cyclical layer-by-layer fashion, with repeating periods of incubation (where no solidification occurs, ending with a nucleation event), depletion (where the excess growth material in the seed particle is rapidly solidified after nucleation), and layer propagation (where the stable nuclei grow into complete layers).[7,8]

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