Disorder-enhanced Auger recombination in III-V alloys

Auger-recombination lifetimes of the excess carriers in p-type III-V alloys are calculated as functions of the chemical composition. The Auger transition involving the conduction band, the heavy-hole band, and the spin split-off band is analyzed. The mixing of an s-like state into the valence band, which is induced by disorder in alloys, is taken into account on the basis of the tight-binding picture. It is shown that the disorder effect is especially significant in alloys whose band-gap energy is small, as in InAs1−xSbx. A plot of the lifetime against the chemical composition of GaSb1−xAsx shows a prominent valley at the composition, where the band-gap energy is nearly equal to but a little larger than the spin-orbit splitting.