Hole impact ionization rates in InP and In_0.53Ga_0.47As

Threshold energies and rates for hole-initiated impact ionization are calculated as functions of energy and direction in k-space. The calculations are based on anisotropic band structure and wavefunctions derived from four-band k.p theory with remote bands taken into account by perturbation theory. It is found that in InP the transitions initiated by carriers in the split-off band are dominant, while for In0.53Ga0.47As transitions initiated by light and heavy holes are also important. Simple algebraic expressions depending on energy and one direction parameter have been developed to approximate proximate the computed transition rates so that these may be used in further calculations or simulations of transport involving hot carriers.