Photoconductivity of the Sulfide, Selenide, and Telluride of Zinc or Cadmium

The highlights of recent photoconductivity research on evaporated, powder, and sintered layers, and on single crystals of photoconductors in the group ZnS, CdS, ZnSe, CdSe, ZnTe, and CdTe are reviewed. The following aspects of photoconductivity are discussed: spectral response, impurity sensitization, electrode contact problems, conductivity, mobility, speed of response, photocurrent vs light intensity, photocurrent vs temperature, infrared quenching, thermally stimulated current and trapping, space-charge limited current, photoconductivity and luminescence, photovoltaic effect, photoemissive effect, and surface photoconductivity. The utility of the concepts of the Fermi-level and demarcationlevel in the description of many photoconductivity phenomena is briefly discussed.