The internal photoelectric effect in InSb with L-band participation

A theoretical calculation of the quantum efficiency of the internal photoelectric effect in InSb is made. In addition to electron and light-hole impact ionisation and intraband thermalising processes (deformation potential, optical polar mode phonons and particle-particle collisions) there are also included the near-horizontal transitions between the Gamma and L conduction bands and between the light-hole and heavy-hole bands. There is good agreement with experiment, with the suggestion that either the L band is lower in energy than previously thought or that there is also the participation of a localised level associated with the L band.