Influence of bias voltage on sputter deposited V2O5 films

Abstract

Vanadium pentoxide (V2O5) thin films were deposited over thoroughly cleaned silicon dioxide (SiO2)-coated silicon (Si) (100) substrates by reactive dc magnetron sputtering technique at various substrate bias voltages keeping the other deposition parameters constant. The thickness value of the films measured using stylus probe technique was in the range of 200 to 230 nm. The films were characterized for their structural, morphological, optical and electrical properties using X-ray diffractometry, field emission scanning electron microscopy, UV-Vis spectroscopy and four-point probe method, respectively. The crystallinity of the films was improved at higher substrate bias voltages, which in turn had influence on the optical bandgap value and electrical resistivity. The optical bandgap of the deposited films were decreased to 2·68 eV from 2·71 eV as a result of removal of defects. The temperature coefficient of resistivity value of V2O5 films deposited at −100 V was found to be −1·9%/K. The results obtained are correlated to the substrate bias voltage.