Growth of ZnO tetrapods for nanostructure-based gas sensors

Standard vapour phase growth process for ZnO tetrapods has been optimized in order to reach a very large yield, a good reproducibility and a single morphology (tetrapods are separated from the other possible ZnO nanostructures). The large yield of the growth and the simple deposition of these nanostructures on an alumina substrate with contacts and heater, allowed us to realize gas sensor prototypes with a relatively low-cost procedure. The obtained ZnO tetrapods-based gas sensors have been tested with different gases (CH3CH2OH, NO2, CO and H2S) and, especially, response values S = 25 and S = 100 have been measured towards 1 ppm and 5 ppm of hydrogen sulphide, respectively.