Investigating the influence of yttrium doping on physical properties of ZnO thin films deposited via spray pyrolysis

This research utilized the spray pyrolysis technique to deposit thin films of pure and Y-doped ZnO. The films were deposited onto glass substrates with constant deposition parameters, but the concentration of Y varied from 1 to 5 wt ratio (wt%). XRD analysis confirmed the presence of hexagonal ZnO phase in all doping concentrations. The crystallite size was determined using Scherrer's equation, revealing an increase from 12.5 nm to 15.2 nm for pure and Y-1wt% films. SEM images were used to determine the average grain size, which was found to be 60.61 nm for pure film, and 116 nm and 106 nm for Y-1wt%, Y-3wt%, and Y-5wt% respectively. Additionally, rod -like structures were observed in the Y-5wt% film. EDX analysis confirmed the presence of Y in the films, with increasing Y concentration in the starting solution leading to higher Y content in the films. The optical band gap remained relatively constant upon doping with Yttrium, while the refractive index and dielectric constant showed a response corresponding to the increase in Y concentration. The electrical conductivity of the pure film was estimated to be 8.06 x 10-4 omega- 1 m- 1. However, it decreased for Y-1wt% and Y-3wt% films, while increasing for Y-5wt%. Finally, the response time was found to be lowest for the Y-1wt% film among all deposited films, while all films exhibited high decay time.