A comparative study of properties of ZnO and CdO thin films

Abstract:ZnO and CdO thin films were prepared on pre-cleaned glass substrates by the chemical bath deposition (CBD) method at 300 K. The thin films were annealed in the air for 1 hr at annealing temperature 400˚C were subjected for structural properties investigations using X-ray diffraction (XRD); formorphological study by means of scanning electron microscopy (SEM);and for optical properties investigations using ultraviolet-visible–near-infrared (UV–VISNIR) spectroscopy. XRD results showed thatboth ZnO and CdO films exhibit crystalline nature. SEM studies revealed the formation of nanosheets like structure forZnO and sunflower like structure for CdO thin film. Electrical resistivity measurement at 300 K showed that the electrical resistivity of both oxides thin films were of the order of 1012Ω.cm was found to decrease with a temperature rise, indicating the normal semiconductor behavior. Furthermore, the optical investigationsincludingband gap energy, extinction coefficient, refractive index and optical conductivity etc, have been investigated and compared with each other. The direct band gap energy values were observed 3.7 eV and 2.7 eV for ZnO and CdO thin film, respectively.