Auger recombination in direct-gap semiconductors: band-structure effects

Abstract

Auger recombination in direct-gap semiconductors is reinvestigated taking into account a realistic band structure instead of using the usual parabolic approximation. It is found that the direct conduction band process is negligible in large-gap semiconductors (Eg>or=0.6 eV), contrary to what has been found using the parabolic approximation. The new values for the probabilities of the valence band process and of the phonon-assisted Auger processes are also found to be smaller, but not by so much. Altogether, smaller values for the total Auger recombination are obtained and these are in agreement with experimental results. In addition, the effect of carrier degeneracy is shown to be weak, apart from where carrier concentrations are extremely high (n>or=1020 cm-3). Finally, the uncertainties involved in the quantitative values of the Auger coefficients are discussed.