High-performance room-temperature TiO2-functionalized GaN nanowire gas sensors

Hybrid gas sensors based on TiO2 functionalized gallium nitride nanowires have been prepared by nanofabrication and comprehensively studied for high-responsivity applications. The devices exhibited a high responsivity (25%) to 500 ppm NO2 assisted with ultraviolet illumination at room temperature. The thickness and doping concentration of TiO2 were engineered to improve the transducer function. The result indicated that an excellent n-type response can be stably obtained for a doping range from 1 x 10(17) cm(-3) to 1 x 10(19) cm(-3). The TiO2 thickness and doping concentration can be further fine-tuned to achieve optimal performance. In addition, a comprehensive device simulation was carried out to understand the device operation and gain insight for optimizing the device performance.