Wafer-scale correlated morphology and optoelectronic properties in GaAs/AlGaAs core-shell nanowires

TL;DR

This study characterizes wafer-scale GaAs/AlGaAs nanowires, revealing that uniform coverage is more critical than material quality variations for consistent optoelectronic performance, aiding scalable device integration.

Contribution

It provides a detailed model linking structural uniformity to optoelectronic properties across a wafer using advanced characterization techniques.

Findings

Emission intensity varies by up to 35%.

Carrier lifetime varies by only 9%.

Uniform nanowire coverage impacts device performance more than material quality.

Abstract

Achieving uniform nanowire size, density, and alignment across a wafer is challenging, as small variations in growth parameters can impact performance in energy harvesting devices like solar cells and photodetectors. This study demonstrates the in-depth characterization of uniformly grown GaAs/AlGaAs core-shell nanowires on a two-inch Si(111) substrate using Ga-induced self-catalyzed molecular beam epitaxy. By integrating Scanning Electron Microscopy and Time Correlated Single-Photon Counting, we establish a detailed model of structural and optoelectronic properties across wafer and micron scales. While emission intensity varies by up to 35%, carrier lifetime shows only 9% variation, indicating stable material quality despite structural inhomogeneities. These findings indicate that, for the two-inch GaAs/AlGaAs nanowire wafer, achieving uniform nanowire coverage had a greater impact on consistent optoelectronic properties than variations in material quality, highlighting its significance for scalable III-V semiconductor integration on silicon in advanced optoelectronic devices such as solar cells and photodetectors.