Characteristics of spray-deposited CdSe thin films

Cadmium selenide thin films were prepared for the first time by the chemical spray-deposition technique using non-toxic selenosulfate as the selenium source. Cleaned grass, conducting glass and metallic substrates were used. The substrate temperature was varied in the range from 300 to 500 degrees C. The films were characterized by X-ray diffraction (XRD), optical absorption and photoconductivity measurements. XRD patterns indicated the presence of single-phase hexagonal CdSe. The resistivity of the as-deposited films was found to vary in the range 10-120 M Omega depending on the substrate temperature. A direct bandgap of 1.65 eV was obtained from optical absorption and spectral response measurements. A photosensitivity value of 3500 was obtained for the films deposited at a substrate temperature of 450 degrees C. (C) 2000 Elsevier Science S.A. All rights reserved.