Radiative recombination, carrier capture at traps, and photocurrent relaxation in PbSnTe : In with a composition close to band inversion

Based on the notions that PbSnTe:In is a direct-gap semiconductor, the radiative-recombination lifetime is calculated, and the photocurrent relaxation and dependences of the instantaneous electron and hole lifetime are calculated under the assumption that PbSnTe:In is a disordered structure containing capture centers. These calculations explain such experimentally observed peculiarities of PbSnTe:In as a high photosensitivity in a wide wavelength range, pinning of the Fermi level, and long-term photocurrent relaxation. Calculations are also compared with experimental data and the possible parameters of photodetectors are evaluated.