Morphological, optical and electrical properties of CdZnO films prepared by sol-gel method

CdZnO films were deposited by the sol-gel spin coating method onto glass substrates. ZnO, Cd(0.25)Zn(0.75)O, Cd(0.50)Zn(0.50)O, Cd(0.75)Zn(0.25)O, CdO films were deposited using different rates of cadmium acetate dehydrate and zinc acetate dehydrate solutions. These values in parentheses refer to the ratio in solution. The dried and annealing temperatures were selected to be 300 deg. C and 500 deg. C in air, respectively. The XRD patterns show polycrystalline nature. It was observed that the crystal structure changes from wurtzite (ZnO) to cubic (CdO) depending on the Zn and Cd proportions in the CdZnO structure. The optical properties of these films have been investigated by means of the optical transmittance measurement. The absorption band edges of films shift from 3.26 to 2.31 eV. The morphological characterizations of the films have been performed by SEM and AFM. In particular, the clusters formed from the nanostructured particles were shown in the SEM image of the Cd(0.75)Zn(0.25)O film. The electrical measurements show that the CdZnO films have semiconducting behaviour and are very sensitive to light.