Auger recombination in bulk InGaN and quantum wells: a numerical simulation study

摘要

The theory of pure-collision and phonon-assisted Auger recombination mechanisms in bulk InGaN alloys is reviewed. The model is based on a Green function formalism and uses realistic electronic structures obtained by nonlocal empirical pseudopotential calculations and phonon spectral density functions determined from first-principles lattice dynamical calculations. The effect of phonons is formally included to the infinite order of perturbation theory by means of the spectral density function which contains summation over all possible phonon momenta. Auger transitions in quantum wells may significantly differ from their bulk counterpart since momentum conservations is lifted along the confining direction. A preliminary analysis indicate that direct Auger transitions in confined structures exhibit an enhancement with respect to the bulk case. The analysis is based on a full-zone description of the electronic structure in which confined and unbound states are represented as a superposition of bulk states of the underlying lattice, thus allowing a fair comparison between Auger coefficients in bulk and quantum wells.