Auger Recombination in Semiconductor Quantum Wells

TL;DR

This paper classifies and analyzes different Auger recombination mechanisms in semiconductor quantum wells, revealing their dependence on well width, temperature, and phonon interactions, and identifying conditions where each dominates.

Contribution

It introduces three fundamentally different Auger recombination mechanisms in quantum wells and explores their dependence on physical parameters, providing new insights into recombination processes.

Findings

Three types of Auger mechanisms identified: thresholdless, quasi-threshold, and threshold.

Thresholdless and quasi-threshold processes dominate in narrow wells.

Resonant phonon-assisted Auger recombination occurs in narrow quantum wells.

Abstract

The principal mechanisms of Auger recombination of nonequilibrium carriers in semiconductor heterostructures with quantum wells are investigated. It is shown for the first time that there exist three fundamentally different Auger recombination mechanisms of (i) thresholdless, (ii) quasi-threshold, and (iii) threshold types. The rate of the thresholdless Auger process depends on temperature only slightly. The rate of the quasi-threshold Auger process depends on temperature exponentially. However, its threshold energy essentially varies with quantum well width and is close to zero for narrow quantum wells. It is shown that the thresholdless and the quasi-threshold Auger processes dominate in narrow quantum wells, while the threshold and the quasi-threshold processes prevail in wide quantum wells. The limiting case of a three-dimensional (3D)Auger process is reached for infinitely wide quantum wells. The critical quantum well width is found at which the quasi-threshold and threshold Auger processes merge into a single 3D Auger process. Also studied is phonon-assisted Auger recombination in quantum wells. It is shown that for narrow quantum wells the act of phonon emission becomes resonant, which in turn increases substantially the coefficient of phonon-assisted Auger recombination. Conditions are found under which the direct Auger process dominates over the phonon-assisted Auger recombination at various temperatures and quantum well widths.