Modulating Carrier Transport Properties at the In₂O₃/ZnCo₂O₄ Heterojunction Interface for Triethylamine Gas Sensing

Enhanced carrier transport properties are essential for achieving superior performance in metal oxide semiconductor (MOS) gas sensors. Heterojunction engineering and bandgap modulation can effectively improve carrier transport characteristics, thereby improving gas-sensing performance. In this work, In₂O₃/ZnCo₂O₄ p-n heterojunction composite with exceptional triethylamine (TEA) response was synthesized via a metal-organic framework (MOF) pyrolysis method. Characterization confirms that the In₂O₃/ZnCo₂O₄ composites possess a morphology composed of cubic structures and hollow microtubes. The incorporation of ZnCo₂O₄ remarkably improved In₂O₃ sensor gas-sensing performance toward TEA, especially regarding selectivity and response. When tested at the optimal operating temperature of 173 °C with 50 ppm TEA, this sensor achieved a remarkable response value of 932, surpassing that of pure In₂O₃ (45) by a factor of approximately 20. Furthermore, it exhibited enhanced selectivity and superior long-term stability relative to pristine In₂O₃ sensor. The integration of microstructural characterization with macroscopic gas-sensing properties reveals the mechanism behind the enhanced gas-sensing performance. Through bandgap modulation strategies and constructing p-n heterojunctions, the carrier transport properties of interfacial materials are enhanced, thereby improving gas-sensing performance. This study introduces an effective pathway for improving the gas sensing performance, thereby contributing valuable insights for the fabrication and real-world application of TEA gas sensors.