Optical Visualization of Radiative Recombination at Partial Dislocations in GaAs

TL;DR

This study uses spatially and spectrally resolved photoluminescence imaging at low temperature to analyze the radiative and non-radiative recombination behaviors of dislocations in ultra-pure GaAs, revealing their roles as luminescence centers.

Contribution

It demonstrates that low-temperature, spatially-resolved photoluminescence imaging can effectively identify and characterize extended defects like dislocations and stacking faults in GaAs.

Findings

Some dislocations are strong non-radiative centers

Other dislocations act as efficient radiative centers

Luminescence bands associated with defects are characterized

Abstract

Individual dislocations in an ultra-pure GaAs epilayer are investigated with spatially and spectrally resolved photoluminescence imaging at 5~K. We find that some dislocations act as strong non-radiative recombination centers, while others are efficient radiative recombination centers. We characterize luminescence bands in GaAs due to dislocations, stacking faults, and pairs of stacking faults. These results indicate that low-temperature, spatially-resolved photoluminescence imaging can be a powerful tool for identifying luminescence bands of extended defects. This mapping could then be used to identify extended defects in other GaAs samples solely based on low-temperature photoluminescence spectra.