Novel single phase vanadium dioxide nanostructured films for methane sensing near room temperature

Methane (CH4) gas sensing properties of novel vanadium dioxide (VO2) nanostructured films is reported for the first time. The single phase nanostructures are synthesized by pulsed dc-magnetron sputtering of V target followed by oxidation in O2 atmosphere at 550 °C. The partial pressure of O2 is controlled to obtain stoichiometric VO2 with the samples showing rutile monoclinic crystalline symmetry and regions of rod shaped nano-architectures. These nanostructured films exhibit a reversible semiconductor to metal transition in the temperature range of 60-70 °C. Gas sensing experiments are carried out in the temperature span from 25 °C to 200 °C in presence of CH4. These experiments reveal that the films respond very well at temperatures as low as 50 °C, in the semiconducting state.