Effect of the RF-power and annealing on the structural, optical, morphological and electrical properties of RF-sputtered V2O5 thin films

Thin films of vanadium oxide were deposited on glass substrates by the radio frequency reactive sputtering from a high purity metallic vanadium target (99.7%) with a diameter of 10 cm. The reactive sputtering was carried out in an argon-oxygen gas mixture containing 10% of O2 and 90% of Ar. The films were deposited at different RF powers (150 W, 200 W, 250 W and 300 W) for a fixed deposition time of 150 min. X-ray diffractograms showed that the deposited thin films crystallized in an orthorhombic V2O5 phase. It was found that the crystallite size varies with the RF power and is maximized using 300 W as an RF power. Scanning Electron Microscopy and Raman scattering analyzes have confirmed the formation of V2O5 thin films. In addition, optical transmittance measurements were performed using a Shimadzu UV-PC spectrophotometer in the 220-2000 nm range. It was observed that the optical band gap of the films decreases with increasing the RF power. Electrical resistivity was found to decrease with increasing the RF power from 150 to 250 W, and then it increases.