Catalyst-free growth of one-dimensional ZnO nanostructures on SiO2 substrate and in situ investigation of their H2 sensing properties

Abstract

One-dimensional (1D) ZnO nanostructures were synthesized on SiO2 substrate by a catalyst-free thermal evaporation method using metallic Zn powders as a raw material. The crystal structure and morphology of the ZnO nanostructures were investigated by SEM, XRD and BET. The results showed that the 1D nanostructures obtained on the SiO2 substrate were hexagonal ZnO. Source temperature and Ar flow rate were an important parameter for the growth of the 1D nanostructures and particular type of ZnO nanostructures could be grown in a specific temperature and Ar flow rate. The H2 sensing properties of prepared 1D ZnO nanostructures were in situ investigated. The sensor exhibited high sensitivity and fast response to H2 gas. The highest sensitivity observed upon exposure to H2 at 1000ppm was 5.3 at 200°C, which demonstrates the potential application of the 1D ZnO nanostructures for fabricating gas sensors compatible with semiconductor technology.