Crystallographic point defects (PDs) can dramatically decrease the efficiency of optoelectronic semiconductor devices, many of which are based on quantum well (QW) heterostructures. However, spatially resolving individual non-radiative PDs buried in such QWs has so far not been demonstrated. Here, using high-resolution cathodoluminescence (CL) and a specific sample design, we spatially resolve, image, and analyse non-radiative PDs in InGaN/GaN QWs. We identify two different types of PD by their contrasting behaviour with temperature, and measure their densities from 1014 cm−3 to as high as 1016 cm−3. Our CL images clearly illustrate the interplay between PDs and carrier dynamics in the well: increasing PD concentration severely limits carrier diffusion lengths, while a higher carrier density suppresses the non-radiative behaviour of PDs. The results in this study are readily interpreted directly from CL images, and represent a significant advancement in nanoscale PD analysis.
@article{arxiv.2103.09702,
title = {Imaging non-radiative point defects buried in quantum wells using cathodoluminescence},
author = {Thomas Weatherley and Wei Liu and Vitaly Osokin and Duncan Alexander and Robert Taylor and Jean-François Carlin and Raphaël Butté and Nicolas Grandjean},
journal= {arXiv preprint arXiv:2103.09702},
year = {2021}
}