High Performance of Ethanol Gas Sensor using Pure ZnO, 3GZO, and 3SZO Nanowires

Abstract

Pure ZnO, Ga(3 wt.%)-doped (3GZO) and Ag(3 wt.%)-doped (3SZO) nano wires based on ZnO have been grown by hot-walled pulse laser deposition (HW-PLD) technique. The doping characteristics of Ga and Ag in ZnO NWs were analyzed by using photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS). We have also fabricated ZnO NW sensors. Among the three ZnO NW sensors, 3SZO NW sensor shows the best property in sensitivity. We have synthesized the NWs on sapphire substrate under the various conditions, such as temperature, time, gas flow, and distance of between target and substrate. The diameter and length of NWs were under 100 nm and several μm, respectively. To confirm the Ga and Ag doping status, we investigated the near band edge (NBE) emission by using low temperature PL and XPS. Significant changes in resistance were observed and the results were compared with ZnO, 3GZO and 3SZO nanawires in terms of the sensitivity. The sensitivities were 97%, 48%, and 203%, repectively when the sensor was measured at 300°C for 1 ppm of ethanol gas.