Temperature dependent structural, electrical and electronic investigation of VO2 (B) thin film

Vanadium dioxide can exist in several polymorphs and among these the layered polymorph VO2 (B) with monoclinic symmetry has numerous applications. In this work, VO2 (B) phase thin film was prepared on quartz substrate via sputtering technique and its temperature dependent structural, electrical and electronic properties were investigated. We have witnessed a broader structural phase transition around 220 K; which encounter significant changes in the lattice constants yet the monoclinic symmetry is retained over a temperature range from 100 K to 380 K. Temperature dependent resistance measurement also exhibited a semi-metal to insulator like transition near 220 K displaying over 2 order of magnitude change in resistance across the transition. Small changes in the oxygen K-edge x-ray absorption spectrum were seen with change in temperature. At low temperature, an additional peak (d|| band) has emerged in the XAS spectra at energy higher than the σ* peak. The appearance of d|| band density of states is associated to the enhanced electron correlation effects driven by the localization of V–V pair's interactions at low temperature.