High performance of nanostructured ZnO film gas sensor at room temperature

Nanostructured ZnO films were synthesized by a simple chemical vapor deposition (CVD) method with different ratios of Zn:Sn in the source materials. The gas sensor using this film exhibits high gas response to ethanol and acetone at room temperature. The gas sensor also has high selectivity which the gas response to ethanol is higher than that to acetone at the same measurement conditions. In addition, visible light plays an important role for the sensitivity of the gas sensor working at room temperature. The typical emission scanning electron (SEM) images reveal that the concentration of Sn in the source materials obviously affects the morphology of the deposited films. XRD patterns of all the samples indicate that no trace of Sn, Sn alloys or Sn oxides were detected in the deposited films. Elemental analysis also shows that the film is composed of Zn and O elements, and no any Sn signals were defected. The sensing mechanism of this kind of room-temperature gas sensor is explained by free electrons random scattering model, and it was found that the nanostructured ZnO films with higher surface-to-volume ratio and higher density of defects will improve the room-temperature gas response. This study demonstrates a prospective approach to obtain high performance room-temperature ethanol gas senor. (C) 2014 Elsevier B.V. All rights reserved.