LAUSR

Heterojunction is an important strategy in designing high performance electrical sensor material and related devices. Herein, a new type of metal-semiconductor hybrid nanoparticles has been successfully used to remarkably sensitize the surface of ZnO nanowires for detecting NO2 with high responses at a broad temperature window ranging from room temperature to 600 oC. These hybrid nanoparticles are comprised of iron oxide nanowires with well dispersed single crystalline Au nanoparticles. The hybrid nanoparticle decorated ZnO nanowires have achieved a giant response as high as 74500 toward NO2 gas, about 42 times that of Au decorated ZnO nanowire sensors. This dramatic enhancement may be attributed to the efficient charge transfer across the Au-Fe2O3 Schottky and Fe2O3-ZnO semiconductor heterojunction interfaces. Due to the incorporation of thermally-stable Fe2O3 nanoparticles as the support of Au nanoparticles, the working temperature of nanowire sensors was successfully extended to higher temperature by 200 oC, from 400 oC to 600 oC. Such a combination of semiconductor heterojunction and semiconductor-metal Schottky contact presents a new strategy to design high performance electrical sensors with high sensitivity, stability, selectivity, and wide operation temperature window, which are potentially suitable for advanced energy systems such as automotive engines and power plants.