Development of microstructure sensor based on hierarchically 2-fold ZnO nanorod arrays on hydrotalcite-like ZnAlCO3 nanosheets

The microstructure sensor based on hierarchically ZnO nanorod (NR) arrays on the pretreated substrate with a thin film of aluminum (Al) has been achieved by using a simple two-step hydrothermal method. The Al on the pretreated substrate is transformed into hydrotalcite-like zinc aluminum carbonate (ZnAlCO3) nanosheets in the alkali hydrothermal environment, which acts as lattice-matched substrate for the self-assembly process of ZnO NR arrays. The investigations of phase purity, morphology, and structure of ZnO NRs reveal that the ZnO NRs grown on the lattice-matched ZnAlCO3 nanosheets are vertically aligned with the average diameter of 80 nm and length of 2 μm. The ethanol sensing properties of the ZnO NR arrays are investigated at different operating temperatures and different gas concentration ranging. The results exhibit high response to ethanol with the response time of 2.8 s when the sensor is exposed to 20 ppm ethanol.