Growth mechanism of hexagonal ZnO nanocrystals and their sensing application

Present paper reports the growth mechanism of hexagonal ZnO nanocrystals (NCs) with their NO2 gas and humidity sensing. Thin film of ZnO was prepared using the zinc acetate with ethanol as precursors. Prepared thin film was annealed at 450 degrees C for 2 h which led to necking and coarsening of nanocrystals. Hexagonal crystalline nature of film was revealed by the XRD with the crystallite size similar to 71 nm and AFM confirmed this fact. Film was exposed to NO2 and moisture separately and variations in resistance with the increasing %RH were recorded. The film gave highest sensing response for 20 ppm NO2 as 150 and for moisture, the highest sensitivity was found as 10.91 M Omega/%RH. (C) 2015 Elsevier B.V. All rights reserved.