Quantum efficiency of [111] oriented p-doped quantum well infrared photodetectors

Orientation dependence of the bound-to-continuum absorption (quantum efficiency) in p-doped semiconductor quantum wells is calculated. As in the [100] direction, the main contribution arises from the transitions between the ground subband and continuum. Due to the larger transition matrix element absorption is 20% higher in the [111] oriented than in the [100] oriented quantum wells, and the peak is slightly shifted towards longer wavelengths.