Imaging non-radiative point defects buried in quantum wells using cathodoluminescence

Abstract

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 $10^{14}$ cm${}^{-3}$ to as high as $10^{16}$ 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.

arXiv commentMain text: 8 pages, 6 figures. Supplementary: 11 pages, 8 figures

References in corpus (5)

• Hundredfold Enhancement of Light Emission via Defect Control in Monolayer Transition-Metal Dichalcogenides
• Imaging of optically active defects with nanometer resolution
• On thresholdless lasing features in high-$\beta$ nitride nanobeam cavities: a quantum optical study
• Field-assisted Shockley-Read-Hall recombinations in III-Nitride quantum wells
• Carrier diffusion in GaN -- a cathodoluminescence study. III: Nature of nonradiative recombination at threading dislocations

Cited by in corpus (3)

• Optical and thermal characterization of a group-III nitride semiconductor membrane by microphotoluminescence spectroscopy and Raman thermometry
• Thermal analysis of GaN-based photonic membranes for optoelectronics
• A Photonic Atom Probe Analysis of the Effect of Extended and Point Defects on the Luminescence of InGaN/GaN Quantum Dots