Effect of sputtering power on the properties of Cd 1 − x Zn xTe films deposited by radio frequency magnetron sputtering

Abstract

Cd 1 − x Zn xTe films were prepared by radio frequency (r.f.) magnetron sputtering from Cd 0.9Zn 0.1Te slices target with different sputtering power (60–120 W). The effects of sputtering power on the properties of Cd 1 − x Zn xTe films were studied using X-ray diffraction (XRD), energy dispersive X-ray (EDX), atomic force microscopy (AFM), ultraviolet spectrophotometer and Hall effect measurements. The composition of the deposited films was determined by EDX. The Cd content was found always to be higher than the Te content, regardless of sputtering power. This behavior may be explained by the preferential sputtering of cadmium atoms in the target. XRD studies suggest that ZnTe secondary phases were coexisted in Cd 1 − x Zn xTe films. The origin of the secondary phase is ascribed to the lowest sticking coefficient of Zn atom. AFM micrographs show that the grain size increases with the sputtering power. The optical transmission data indicate that shallow absorption edge occurs in the range of 750–850 nm, and the sputtering power does not have a clear effect on the optical absorption coefficient. In Hall Effect measurements, the sheet resistivities of the deposited films are 1.988 × 10 8, 8.134 × 10 7, 8.088 × 10 7 and 3.069 × 10 7 Ω/sq, respectively, which increase with the increasing of sputtering power.