Carrier localization mechanisms in InGaN/GaN quantum wells

TL;DR

This paper investigates how alloy composition fluctuations, well width variations, and internal fields in InGaN/GaN quantum wells influence carrier localization, supported by numerical calculations and photoluminescence simulations.

Contribution

It provides a comprehensive numerical analysis of carrier localization mechanisms considering alloy disorder, well width fluctuations, and internal fields in InGaN/GaN quantum wells.

Findings

Alloy fluctuations can localize electrons and holes.

Well width fluctuations contribute to electron localization.

Simulated photoluminescence spectra agree with experimental data.

Abstract

Localization lengths of the electrons and holes in InGaN/GaN quantum wells have been calculated using numerical solutions of the effective mass Schr\"odinger equation. We have treated the distribution of indium atoms as random and found that the resultant fluctuations in alloy concentration can localize the carriers. By using a locally varying indium concentration function we have calculated the contribution to the potential energy of the carriers from band gap fluctuations, the deformation potential and the spontaneous and piezoelectric fields. We have considered the effect of well width fluctuations and found that these contribute to electron localization, but not to hole localization. We also simulate low temperature photoluminescence spectra and find good agreement with experiment.