On the theory of the photoelectric effect in surface-graded-gap semiconductors

A correct mathematical model of interband carrier photogeneration by low-intensity optical radiation in surface-graded-gap semiconductors is constructed and analytically considered for the case of strong, including step-like, variations in the graded-gap field in the transition region adjacent to the homogeneous layer. The dependence of the degree of the blocking of surface-photocarrier recombination on the parameters of the graded-gap surface layer is analyzed. The conditions for achieving the limiting efficiency of the photoelectric response of semiconductors to low-intensity optical radiation due to the graded-gap surface layer are determined.