Formation of Transparent and Photo Conducting Films by High Temperature Chemical Conversion of Solution Grown Precursor Films

Abstract

Abstract The formation of photoconducting ZnO and transparent conducting CdO films by high temperature oxidation and thermal decomposition of chemically deposited ZnS and Cd(OH)2 precursor films respectively is reported. The ZnS to ZnO and Cd(OH)2 to CdO conversions were confirmed by x-ray diffraction (XRD)2 electrical and optoelectronic studies. As deposited ZnS and Cd(OH)2 films exhibited very low dark conductivity and no photoconductivity. Air oxidation of ZnS films at about 400°C for at least 15 minutes converted them to ZnO films with higher dark and photoconductivity. Cd(OH)2 to CdO conversion occurred at about 300°C. CdO films exhibited a dark conductivity of the order of 103 (Ωcm)-1 and an optical transmittance in the range of 90%. These characteristics of ZnO and CdO films make them suitable candidates for the development of low cost photoconductors and solar cell structures.