Highly sensitive and low detection limit of ethanol gas sensor based on hollow ZnO/SnO2 spheres composite material. - Liu, Jiangyang; Wang, Tianshuang; Wang, Boqun; Sun, Peng; Yang, Qiuyue; Liang, Xishuang; Song, Hongwei; Lu, Geyu (Sensors & Actuators B: Chemical, 2017)