Anti-reflective and luminescent GaAs/AlGaAs core–shell nanowires on Si wafer with 1 ns carrier lifetime up to 400 K

Abstract

We investigated the structural and optical properties of GaAs/Al0.8Ga0.2As core–shell nanowires (NWs) grown on a 2-in. Si wafer. The NWs exhibit low reflectance (<2%) across the visible to near-infrared range, attributed to their complex structure, intrinsic GaAs absorption, and a uniform NW density of approximately 3 × 108 cm−2 with an average length of 5 μm. Optical analyses based on Kubelka–Munk transformation and Tauc plot revealed minimal deviation between the estimated bandgap and the photoluminescence (PL) peak position. Temperature-dependent PL measurements between 300 and 400 K showed a weak intensity reduction and a characteristic temperature of 170 K, indicating stable emission properties within this range. Time-resolved-PL measurements demonstrated carrier lifetimes exceeding 1 ns up to 400 K, with a surface recombination velocity comparable to high-quality GaAs/AlGaAs NWs. These findings provide key insights into the optical performance and thermal stability of the NWs, highlighting their potential for optoelectronic devices operating at elevated temperatures.