Effect of temperature on structural, optical and electrical properties of pulsed-laser deposited W-doped V2O5 thin films

We have successfully deposited novel single phase W-doped orthorhombic vanadium pentoxide nanostructured thin films by pulsed laser deposition technique. It is seen that there is a strong influence of deposition temperature on the structure, optical and electrical properties of W-doped V2O5 films. The morphology of the apparently amorphous films deposited at 423 K turns into films with homogeneous distribution of crystalline nanorods with 10-20 nm diameter at 523 K and 623 K. The growth mechanism leading to the transformation of a 2D film to a nanorod-like morphology is described. Direct optical band gap of the W-doped V2O5 films decreased from 2.61 eV (at 623 K) to 2.18 eV (at 423 K). Temperature dependent characteristics of the electrical conductivity (resistivity) in the temperature range 300 K-500 K were investigated, and the underlying mechanism in the increase in activation energy is well understood.