Annealing effects on $\mathrm{V}_2\mathrm{O}_{5-x}$ thin films deposited by non reactive sputtering

Thin films of vanadium oxide $(\mathrm{V}_2\mathrm{O}_{5-x})$ were prepared by rf magnetron sputtering process and are heat treated to study the annealing effect. As-deposited thin films are amorphous in nature and crystallinity is improved by annealing the sample. Thin layers with high density and small grain size varying from $36$ nm to $70$ nm were seen in the FESEM images of as-deposited thin films. In the case of annealed thin films, it has been transformed to thin elongated rod like structure with $202.5$ nm length and an average diameter of approximately $48$ nm. Optical properties were studied by using UV-Vis-NIR spectrophotometer and the reduction in transmission in annealed thin films is due to the crystalline nature of thin films. Studies were done on the samples by taking photoluminescence and Laser Raman spectra.