| 초록 |
We investigate the laser-induced oxygen vacancies and their roles for improving NO2 sensing performance in the SnO2 nanowire gas sensors. For this purpose, a KrF excimer laser that emits ultraviolet light with a wavelength of 248 nm in a short periodic pulse of 20 nm was used as a room-temperature defect engineering tool. In this experiment, the irradiation of the high-intensity laser was found to effectively implant the bridging oxygen vacancies on the surface of SnO2 nanowires. At the same time, it considerably increases the surface area of the sensing materials by modifying morphological features. The laser-driven physicochemical modifications bring a positive effect on the sensing performance. Indeed, even at the relatively low temperature of 100 oC, the irradiated SnO2 sensors exhibit 14-times greater responses toward NO2 gas and two-times faster recovery times compared with the non-irradiated sample. Based on our theoretical prediction from DFT calculations, the formation of the bridging oxygen vacancies is found to play a key role in facilitating NO2 adsorption on the SnO2 surface, thereby promoting sensing performance. |
