Facile Producing Single Phase CdO Films Prepared Using Thermal Evaporation via Optimizing Annealing Temperature: Their Application in Photodiodes

CdO powder is used to prepare films using high vacuum thermal deposition technique. The produced films are annealed at different temperatures in air atmosphere. Crystal structure identification reveals that the as–deposited films and annealed at 200 °C are composed of a mixture Cd and CdO phases. By annealing at 300 °C, CdO single phase is obtained. The surface morphology of the as-deposited and annealed films is investigated by field emission scanning electron microscope. Besides, the transmittance and reflectance spectra are measured and the optical band gap of different films is evaluated. The current–voltage characteristics of Al/CdO/InP/AuZn diodes based on CdO films are measured as a function of annealing temperature. Under illumination, the diodes show response to the light. The diode based on single phase CdO is exposed to different light intensity in which the mechanism of operation is found to be bimolecular recombination mechanism.