Enhancing the electrical parameters of ZnO films deposited using a low-cost chemical spray technique through Ta doping

Abstract

Tantalum doped ZnO thin films (doping levels – 0, 1, 3 and 5 at %) were deposited onto glass substrates using a simplified spray pyrolysis technique by employing a perfume atomizer for the first time. The effects of Ta doping level on electrical, optical and structural properties along with surface morphology of ZnO films were studied. EDAX and FTIR studies confirm the presence of the dopant in the prepared film. The chemical states of the constituent elements were analysed through XPS studies. The average optical transmittance of the film is over 90%. Even though the intensity of (001) peak increases at the expense of (002) plane with Ta doping, the direction of preferential growth is unaltered. The FESEM analysis shows that the dopant alters the grain size of the films. A minimum electrical resistivity of 2.05 × 10−3 Ω cm was obtained at the doping level of 1 at%. The obtained good quality factor (1.584 × 10−4 (Ω/sq.) −1) of the film at 1 at% of Ta doping level makes it a potential candidate for several opto-electronic devices like transparent electrodes, thin film transistors and many other functional devices.