Al doped ZnO nanogranular film fabricated by layer-by-layer self-assembly method and its application for gas sensors

ZnO is one of the most promising materials for gas sensor. Nanogranular films with ultrahigh surface-to-volume ratio have great potential in gas sensor application. In this paper, Al doped ZnO nanogranular films were fabricated by layer-by-layer (LBL) self-assembly method and the gas sensitivity of ZnO films were investigated. The results show that sensitivity of Al:ZnO gas sensors is up to 12 against 20000 ppm hydrogen, while the response time and recovery time of the sensor are only 12 s and 25 s respectively. The high sensitivity is attributed to the high surface-to-volume ratio of nanogranular and porous structure of self-assembled films.