Alloy disorder effects on the room temperature optical properties of GaInNAs quantum wells

TL;DR

This study investigates how alloy disorder affects the optical properties of GaInNAs quantum wells at room temperature, revealing a correlation between nitrogen content, spectral shifts, and carrier trapping phenomena.

Contribution

It provides new insights into the impact of alloy disorder on optical density of states and carrier dynamics in GaInNAs quantum wells.

Findings

Red shift increases with nitrogen content

Carrier transition from quasi-thermal to trapped states

Electron temperature aligns with carrier trapping model

Abstract

The effect of alloy disorder on the optical density of states and the average room temperature carrier statistics in GaInNAs quantum wells is discussed. A red shift between the peak of the room temperature photoluminescence and the surface photovoltage spectra, that systematically increases with the nitrogen content within the quantum wells is observed. The relationship between this Stokes' shift and the absorption linewidth in different samples suggests that the photoexcited carriers undergo a continuous transition, from being in quasi-thermal equilibrium with the lattice to being completely trapped by the quantum dot-like potential fluctuations, as the nitrogen fraction in the alloy is increased. The values of the 'electron temperature' inferred from the photoluminescence spectra are found to be consistent with this interpretation.