Remarkably Enhanced Methane Sensing Performance at Room Temperature via Constructing a Self-Assembled Mulberry-Like ZnO/SnO2 Hierarchical Structure

Development of metal oxide semiconductors-based methane sensors with good response and low power consumption is one of the major challenges to realize the real-time monitoring of methane leakage. In this work, a selfassembled mulberry-like ZnO/SnO2 hierarchical structure is constructed by a two-step hydrothermal method. The resultant sensor works at room temperature with excellent response of similar to 56.1% to 2000 ppm CH4 at 55% relative humidity. It is found that the strain induced at the ZnO/SnO2 interface greatly enhances the piezoelectric polarization on the ZnO surface and that the band bending results in the accumulation of chemically adsorbed O similar to 2 ions close to the interface, leading to significant improvement in the sensing performance of the methane gas sensor at room temperature.