Auger recombination in narrow band quantum well CdxHg1-xTe/CdyHg1-yTe heterostructures

TL;DR

This study combines theoretical modeling and experimental validation to analyze Auger recombination in narrow-gap HgCdTe quantum wells, optimizing conditions for far-infrared lasing and revealing dominant recombination channels at high carrier densities.

Contribution

It provides a comprehensive model of Auger recombination in HgCdTe QWs, validated by experiments, and identifies optimal compositions for infrared laser applications.

Findings

Good agreement between theory and experiment using a single fitting parameter.

Optimal QW composition for 31 μm lasing is 6.5% cadmium.

At high carrier densities, plasmon emission dominates over Auger recombination.

Abstract

We present detailed theoretical and experimental studies of Auger recombination in narrow-gap mercury cadmium telluride quantum wells (HgCdTe QWs). We calculate the Auger recombination probabilities as functions of non-equilibrium carrier density, temperature and composition of quantum wells taking into account the complex band dispersions and wave functions of the structures. Our theory is validated by comparison with measured kinetics of photoconductivity relaxation in QW with band gap of 76 meV at a temperature of 77 K. We find good agreement of theory and experiment using a single fitting parameter: the initial density of non-equilibrium carriers. The model is further used to optimize the composition of QWs and find the most suitable conditions for far-infrared lasing. Particularly, for band gap of 40 meV (lasing wavelength {\lambda}=31 \mu m) the lasing is favored in QWs with 6.5% cadmium fraction. We also find that at very large non-equilibrium carrier densities, the main recombination channel is associated with emission of two-dimensional plasmons and not with Auger process