Strengthening the Interactions Between Metal and Semiconductor Heterostructures via Microwave Synthesis for Chemiresistor Applications

Designing metal-semiconductor-based core-shell nanostructures with strong interactions is emerging as a unique component for chemiresistor applications. Here, we have developed an effective hydrogen (H₂) gas sensor based on Au-In₂O₃ core-shell nanostructures, which were synthesized through a short-time microwave hydrothermal process. At an optimal temperature of 375 °C, the device based on Au-In₂O₃ displays a high sensitivity of ~42, which is five times greater than that of the In₂O₃ toward 100 ppm of H₂ gas. Moreover, the Au-In₂O₃ sensor showed higher selectivity toward H₂ gas and stability over a long period. The excellent H₂ gas-sensing performance of Au-In₂O₃ core-shell nanoparticles can be credited to the sensitization and Au catalytic effect core, and their strong interaction with the In₂O₃ component. Our work not only accounts for a facile synthesis approach for Au-In₂O₃ core-shell nanoparticles by synergistic properties of Schottky heterojunctions, but also offers a new insight into how strong metal-semiconductor interactions (SMSIs) play a dynamic role in developing high-performance gas-sensing devices.