Structural and optical properties of (001)-oriented vanadium pentoxide nanorods

Abstract

In this study, the authors report on the structural and optical properties of vanadium pentoxide (V2O5) nanocrystalline thin films at different substrate temperatures ranging from room temperature to 450°C on glass substrates using vacuum evaporation technique. The deposition temperature was found to have significant effect on the structural, morphology and optical properties of these films. The X-ray diffraction pattern showed the formation of highly (001)-oriented, orthorhombic V2O5 films with high degree of crystallinity. Interestingly, field-emission scanning electron microscopy and atomic force microscopy analyses revealed the formation of uniformly distributed V2O5 nanorods (≈138 nm) at a deposition temperature of 350°C. A significant decrease in transmittance was observed in the V2O5 films deposited above 350°C, which could be attributed to the scattering light loss caused by the increase in surface roughness of the films at high deposition temperatures. The optical parameters such as refractive index (n), extinction coefficient (k) and band gap were also calculated from the transmittance and absorption curves over the spectral range of 300–800 nm. The formation of highly oriented V2O5 nanocrystalline rods will open avenues in various energy applications.