Highly sensitive and selective triethylamine-sensing properties of nanosheets directly grown on ceramic tube by forming NiO/ZnO PN heterojunction

Chemiresistive gas sensors with high sensitivity, selectivity and reliable fabrication potency for specific gas have been now expected for many applications. A highly sensitive and selective nanostructured triethylamine (TEA) gas sensor has been fabricated successfully by designing PN heterojunction consisting of ZnO nanosheets and NiO nanoparticles. The ZnO nanosheets directly grew on Al2O3 ceramic tubes by introducing a seed layer with a simple and cost-effective hydrothermal method. By employing pulsed laser deposition (PLD) method, the construction of NiO/ZnO PN heterojunction is highly controllable and reproducible. In comparison with ZnO nanosheet, the NiO/ZnO nanoparticle/nanosheet heterojunction exhibits much better sensing property to TEA gas. The depletion layer formed at the PN junction interface in NiO/ZnO sensor can greatly increase the resistance in air and decrease the resistance in TEA gas. Due to the general working principle and controllable growth strategy, this study provides a way for design and fabrication of the chemiresistive gas sensors with high performance.