UV-light enhanced gas sensor based on Ga doped ZnO for ultra-high sensitive and selective n-butanol detection

N-butanol gas is a common volatile organic compound (VOC) that can pose a threat to human health and pollute the atmospheric environment. However, the n-butanol gas sensors suffer from low response and selectivity. Herein, we synthesized the Ga-doped ZnO (ZOG) sensors by one-step hydrothermal treatment and subsequent calcination. The oxygen vacancies content of 1-ZOG has increased by 46 % compared to pure ZnO. Rich oxygen vacancies can increase the response signal of 1-ZOG to 174.78 in darkness for 100 ppm n-butanol, which is 2.4 times that of ZnO. Furthermore, the gas sensing performance of 1-ZOG is improved by light excitation. Under UV irradiation, the response of 1-ZOG sensor to 100 ppm n-butanol is 3.6 times that of pure ZnO, up to 636.81. Meanwhile, the response signal of 1-ZOG to n-butanol is at least 6.32 times that of other gases under UV light, showing ultra-high selectivity. This study proved that both Ga doped and photo-excited are effective strategies for improving the sensitivity and selectivity of ZnO based gas sensors.