Near room-temperature triethylamine sensor constructed with CuO/ZnO P-N heterostructural nanorods directly on flat electrode

•Nanostructured triethylamine gas sensor with high response can work at near room temperature.•The CuO/ZnO nanorod P-N heterostructure were directly grown on flat Al2O3 substrate.•The depletion layer formed at the CuO/ZnO interface enhanced the sensor performance. Metal oxide-based chemiresistive gas sensors working at room temperature with high sensitivity for specific gas have been expected for many applications. Here, a near room-temperature and high-response triethylamine (TEA) gas sensor has been successfully fabricated by designing CuO/ZnO P-N heterostructure. By introducing a seed layer, ZnO nanorods directly grew on flat Al2O3 substrate with a facile and cost-effective hydrothermal method. Then, CuO nanoparticles were loaded onto the surface of ZnO nanorods to form P-N heterostructures via a simple wet-chemical method. The CuO-nanoparticles/ZnO-nanorods heterostructure exhibits higher response to 50ppm TEA gas than that of pristine ZnO nanorods even at working temperature as low as 40°C, owing to the formation of P-N heterojunction. The enhanced gas-sensing properties of CuO/ZnO sensor were discussed with a CuO/ZnO P-N heterojunction model in terms of depletion layer and modulation of potential barrier height.