Enhancement of UV detection properties of ZnO thin films via Ni doping

Abstract

Abstract In this work, pure and Ni-doped ZnO thin films have been deposited onto glass substrates using the spray pyrolysis technique. All films were deposited at constant deposition parameters but the Ni content was changed from 0 to 7 weight (wt) %. XRD results revealed the formation of a hexagonal ZnO phase whilst no other phases were detected. The crystallite size was determined using Scherrer’s equation and found to be 45.9 nm for the pure film. Scanning electron microscope images show the formation of irregular grains with a broad size distribution. The existence of Ni in the deposited films was confirmed using energy dispersive spectroscopy (EDX), where the Ni content in the film increases as the weight % increases in the starting solution. The optical band gap was determined and found to be 3.3 eV for the pure ZnO films, which was reduced with Ni doping. The performance of the deposited films for UV radiation has been examined for the 365 nm wavelength and at different applied potentials and constant power. The rise and decay times for doped films were observed to exhibit faster rise/recovery as compared to pure films. The minimum response time was found to be 0.09 s for Ni-7 wt% film and the minimum decay time is 0.07 s for Ni-1 wt%.