Investigation on CH 4 sensing characteristics of hierarchical V 2 O 5 nanoflowers operated at relatively low temperature using chemiresistive approach

Methane (CH ) gas, the second most potent greenhouse gas share a substantial role in contributing to the global warming and it is a necessary pre-requisite to detect the release of CH into the environment at its early stage to combat climate change. In that front, this work is focussed to develop an effective CH gas sensor using vanadium pentoxide (V O ) thin films that works at an operating temperature of ∼100 °C. To understand the effect of sputtering power towards the structural characteristics of V O films, X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) analysis were performed from which the orthorhombic polycrystalline structure of V O thin films was confirmed with varied texture co-efficient. Further, the surface elemental studies using X-ray photoelectron spectroscopy (XPS) confirmed the prominence of V oxidation state from the binding energy of V2p and O1s peak. The effect of sputtering power on the growth of different nanostructures were observed using field-emission scanning electron microscopy (FE-SEM). The critical role of adsorption and desorption kinetics of the deposited nanostructures were explained through first order kinetics based on Elovich model and the phase stability of different nanostructures were evaluated using Raman spectral analysis. This work achieved the sensor response of about ∼8% towards CH at an operating temperature of 100 °C towards 50 ppm concentration.