Improvement of sensing characteristics of radio-frequency sputtered tungsten oxide films through surface modification by laser irradiation

To enhance sensing characteristics of semiconductor gas sensors, the surface morphology of sensing layer modified by laser irradiation was performed. Tungsten oxide (WO3) thin-films grown on Si/SiO2 wafers by radio-frequency sputtering were annealed and then irradiated by an excimer laser under various laser power densities. The effect of the laser irradiation on film surface morphology was studied by X-ray diffraction and atomic force microscopy. Gas sensors based on the laser-irradiated WO3 films demonstrated better responses to low concentration NO2 compared with the sensors without laser irradiation.