Tuning the Crystallite Size of Metal Doped V₂O₅Thin Films via Annealing

In this study, a Nebulizer Spray Pyrolysis (NSP) approach with wt%, 2 wt%, and 7wt% Sn doping levels was used to successfully deposit V2O5 thin films on a glass substrate. The deposited films were then annealed at 400° C, and the effect of annealing was analyzed using X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). XRD analysis confirms that Sn doping enhances the crystallinity of the annealed V2O5 thin films. The crystallite size increased from 0.1752 nm (undoped) to 0.2568 nm (7 wt% Sn doping), while the dislocation density decreased from 3.26 × 1019 lines /m2 to 1.52 × 1019 lines/m2 and microstrain decreased from 1.185 × 10- to 0.78 × 10-3, respectively. SEM analysis confirmed significant microstructural modifications, with 2 wt% Sn doping resulting in the most uniform, compact, and crack-free thin film. However, excessive Sn doping at 7 wt% Sn doping compromised film stability by causing phase segregation, microcracks, and grain aggregation. These results suggest that 2 wt% Sn doping provides the best compromise between film quality and functional characteristics, making Sn -doped annealed V2O5 a viable option for gas sensing applications.