Structural, optical, and electrical properties of Zn-doped CdO thin films fabricated by a simplified spray pyrolysis technique

Abstract

Thin films of zinc-doped cadmium oxide with different Zn-doping levels (0, 2, 4, 6, and 8 at%) were deposited on glass substrates by employing an inexpensive, simplified spray technique using perfume atomizer at relatively low substrate temperature (375 °C) compared with the conventional spray method. The effect of Zn doping on the structural, morphological, optical, and electrical properties of the films was investigated. XRD patterns revealed that all the films are polycrystalline in nature having cubic crystal structure with a preferential orientation along the (1 1 1) plane irrespective of Zn-doping level. Zn-doping level causes a slight shift in the (1 1 1) diffraction peak toward higher angle. The crystallite size of the films was found to be in the range of 28-37 nm. The band gap value increases with Zn doping and reaches a maximum of 2.65 eV for the film coated with 6 at% Zn doping and for further higher doping concentration it decreases. Electrical studies indicate that Zn doping causes a reduction in the resistivity of the films and a minimum resistivity of 15.69 X cm is observed for the film coated with 6 at% Zn.