Highly sensitive room temperature hydrogen sensor based on undoped SnO2 thin films

Abstract

Abstract The physicochemical property of semiconductors play a vital role in enhancing the gas sensing performance of the metal oxides that can operate in real time atmosphere. Here in, hydrogen (H2) sensing behaviour of SnO2 thin films prepared using DC reactive magnetron sputtering technique by varying the cathode power are reported. From X-ray diffraction (XRD) analysis, polycrystalline nature of SnO2 thin films were observed and it exhibited rutile tetragonal structure and the crystallite size was found to be increased from 17.6 to 38.8\u202f nm. From the morphological study taken from field emission-scanning electron microscopy (FE-SEM), the nano granular like morphology was observed. As a result of increase in cathode power, the optical bandgap reduced from 3.5 to 3.3\u202f eV. The influence of cathode power on the sensitivity, response and recovery time have been studied. This report elucidates the H2 sensing response towards undoped SnO2 thin films of about 4.7\u202f at room temperature towards 100\u202f ppm concentration.