Spectral Distribution, Optical and Thermal Quenching of Longitudinal Photoconductivity in CdSe<i>/</i>SnO₂ Films

A method has been developed for producing a photosensitive film made of CdSe, including thermal vacuum deposition of CdSe on a substrate with a transparent layer of SnO2 and thermal treatment of the freshly prepared film in a quasi-closed chamber in air in the presence of CdCl2 or CuCl2 vapors, ensuring uniform diffusion of the sensitizing substances. From the analysis of the longitudinal photoconductivity spectrum it is shown that freshly prepared cadmium selenide films have local levels with the activation energy: EV + 0.63; EV + 0.8; EV + 0.925; EC − 0.55 and EC − 0.41 eV. After heat treatment in air in the presence of CuCl2 new photosensitive centers are formed: complexes of the chlorine atom with a cadmium vacancy with the activation energy of (EV + 0.42 ± 0.05) eV, cadmium vacancies −EV + (0.6 ± 0.05), as well as a fast recombination center EV − (0.95 ± 0.05) eV.