Aerotaxy: gas-phase epitaxy of quasi 1D nanostructures

Sudhakar Sivakumar,Martin H Magnusson,Reine Wallenberg,Lars Samuelson,Wondwosen Metaferia,Magnus Heurlin,Jonas Johansson,Knut Deppert,Axel R Persson

doi:10.1088/1361-6528/abbc23

Sudhakar Sivakumar, Martin H Magnusson + Show 7 more

Open Access

https://doi.org/10.1088/1361-6528/abbc23

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Abstract

Cost- and resource-efficient growth is necessary for many applications of semiconductor nanowires. We here present the design, operational details and theory behind Aerotaxy, a scalable alternative technology for producing quality crystalline nanowires at a remarkably high growth rate and throughput. Using size-controlled Au seed particles and organometallic precursors, Aerotaxy can produce nanowires with perfect crystallinity and controllable dimensions, and the method is suitable to meet industrial production requirements. In this report, we explain why Aerotaxy is an efficient method for fabricating semiconductor nanowires and explain the technical aspects of our custom-built Aerotaxy system. Investigations using SEM (scanning electron microscope), TEM (transmission electron microscope) and other characterization methods are used to support the claim that Aerotaxy is indeed a scalable method capable of producing nanowires with reproducible properties. We have investigated both binary and ternary III–V semiconductor material systems like GaAs and GaAsP. In addition, common aspects of Aerotaxy nanowires deduced from experimental observations are used to validate the Aerotaxy growth model, based on a computational flow dynamics (CFD) approach. We compare the experimental results with the model behaviour to better understand Aerotaxy growth.

Highlights

Over the past three decades, 1D nanostructures have attracted substantial interest due to their outstanding opto-electronic properties [1, 2]
Depending on the capability of the growth technology used, nanowires with precise dimensions, crystallinity and materials composition [11] can be manufactured. metal organic vapor phase epitaxy (MOVPE) is a bottom-up approach that has been used for manufacturing semiconductor nanowires since the early 1990s [12] and can fabricate nanoscale structures with surface quality on par with molecular beam epitaxy (MBE)
Our experiments in Aerotaxy were performed at temperatures above this eutectic point for both binary and ternary semiconductor systems, and the maximum growth rate we observed is much higher than that predicted by VSS, we adopt the VLS framework to understand nanowire growth

Summary

Introduction

Over the past three decades, 1D nanostructures have attracted substantial interest due to their outstanding opto-electronic properties [1, 2]. Metal organic vapor phase epitaxy (MOVPE) is a bottom-up approach that has been used for manufacturing semiconductor nanowires since the early 1990s [12] and can fabricate nanoscale structures with surface quality on par with molecular beam epitaxy (MBE) Both methods suffer in throughput from batch processing and demand expensive crystalline substrates, increasing the overall production cost [13]. Bell laboratories [17] proposed the vapor–liquid–solid (VLS) growth model in 1964 to explain sub-mm Si wire growth They proposed that the liquid Au droplet on the substrate acts as a sink or enhances cracking of the precursors in the vapor phase that subsequently precipitates into the solid crystal phase. Our experiments in Aerotaxy were performed at temperatures above this eutectic point for both binary and ternary semiconductor systems, and the maximum growth rate we observed is much higher than that predicted by VSS, we adopt the VLS framework to understand nanowire growth

Aerotaxy technology

Growth results and discussion

Wire growth and process modelling

Conclusions