Physical properties of La-doped ZnO thin films prepared by spray pyrolysis technique

In this research, La-doped ZnO thin films were produced using the spray pyrolysis method to study the influence of La concentration. The films were doped with La at different concentrations ranging from 1 to 5 weight percent (wt%). Various physical properties of the deposited films were examined using a variety of techniques. X-ray diffraction analysis indicated the presence of a hexagonal ZnO phase as the only crystalline phase in all deposited films. The crystallite size was calculated using Scherrer's equation. Field emission scanning electron microscopy (FE-SEM) images revealed the formation of large grains exceeding the crystallite size, with the smallest grain size of 143.5 nm observed in the La-1 wt% film. Energy dispersive x-ray (EDX) analysis confirmed the existence of La in the deposited films. The optical band gap values were found to increase from 2.7 to 3.3 eV with increasing La content. Notably, a significant decrease in decay time was noted in UV sensing performance at La concentrations of 3 and 5 wt%.