Unveiling the influence of thermal treatment on physical properties of Cu doped CdSe films for photovoltaic applications

In view of cost effectiveness, the CdSe material could be urged as promising absorber to thin film based photovoltaic devices. The properties of CdSe films could be effectively modulated with transition metal doping (e.g., Copper) and thermal treatment (TT) for absorber layer photovoltaic applications. Herein, 5% Cu doped CdSe films are developed using thermal evaporation followed by thermal treatment at 150 °C, 250 °C and 350 °C for one hour. Structural studies divulge crystallization of films in mixture of cubic and hexagonal phases where intensity and crystallite size corresponding to (111) predominant peak is boosted from 46 nm to 52 nm with thermal treatment. Ohmic characteristics of films are validated by electrical analysis whereas surface topographical analysis designates cylindrical and hillock features. Variation in optical absorbance and blue shift in bandgap from 1.61 eV to 1.71 eV has been observed. Morphological micrographs indicate formation of nano-spherical grains having average diameter of 75 nm, 77 nm, 78 nm and 122 nm for pristine, TT1, TT2 and TT3 samples, respectively. Present concise investigation signifies that properties of CdSe:Cu films could be meticulously engineered with thermal treatment for absorber layer applications.