Performances of In-doped CuO-based heterojunction gas sensor

In this work, the pure and In-doped CuO nanostructure was successfully synthesized by a simple one-step hydrothermal method. X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and X-ray photoelectric spectroscopy were employed for characterization of the structure and morphology of the as-prepared nanostructure materials. Then, the gas sensing properties of the pure and In-doped CuO nanostructure were investigated. Compared with pure CuO, the sensors based on 2 mol% In-doped CuO exhibited enhanced gas sensing and low working temperature obviously. The response to 300 ppm ethanol gas reached to 67.1 at 116 °C, which was almost 9.5 times higher than that of pure CuO. The flow and recombination of carriers at the n–p junction are the main reason for the decrease in the carrier concentration of In₂O₃/CuO gas sensors in reducing gas. Therefore, we believe that the change of carrier concentration and material surface caused by In doping could be responsible for the enhancement of the gas sensing properties.