Theory of intrinsic recombination at zero temperature in small gap semiconductors

A theory of intrinsic recombination at zero temperature is developed. Numerical results in a wide range of excitation and doping concentrations are given for a model adapted to PbS 0.1 Se 0.9 . In order that first‐order Auger recombination is possible a minimum value of majority carrier concentration has to be reached. Consequently, a finite small signal lifetime only exists if doping concentration N D > N D min , where for PbS 0.1 Se 0.9 N D min ≈ 4.5 × 10 18 cm −3 in case of parabolic model and N Dmin ≈ 9 × 10 19 cm −3 in case of Kane model of band structure. Radiative recombination rate only depends on minority carrier concentration p . At strong excitation the radiative lifetime behaves like p −213 in parabolic and like p −113 in Kane band approximation. Quantum efficiency η of radiative processes in dependence on N D decreases steplike near N D ≈ N D min .