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.