Effect of Cu doping concentration on H2S gas-sensing properties of Cu-doped SnO2 thin films

Metal oxide-based gas sensors doped with metal element have attracted many researchers due to their enhancement in physico-chemical properties as compared to pristine counterpart. Herein, a novel idea of tailoring the structure and properties by controlling the doping percentage is used to obtain the optimum performance characteristics. The present communication reports synthesis of pristine SnO2 and in situ Cu-doped SnO2 films using simple chemical spray pyrolysis technique to study H2S gas-sensing characteristics. The synthesized pristine and Cu-doped SnO2 films were characterized using X-ray diffraction(XRD), scanning electron microscopy(SEM) and UV-visible spectroscopy to reveal their structural, morphological, and optical properties, respectively. To ascertain the presence of CuO/SnO2 interface, transmission electron microscopy(TEM) is carried out. Optimum doping concentration and operating temperature is determined by studying the gas-response characteristics for various doping concentrations at different operating temperatures. For this combination of optimum doping concentration and operating temperature, repeatability as well as response and recovery time towards H2S gas are systematically studied.