Effects of reaction time on the morphological, structural, and gas sensing properties of ZnO nanostructures

Morphological transformation was achieved from ZnO hexagonal needle-like rods to hexagonal flower-like rods by varying the reaction growth time using the hydrothermal method. Optical bandgap energies were calculated from the absorption spectra using UV‐vis spectroscopy. Gas sensing properties of flower-like hexagonal ZnO structures at 50 ppm for ethanol (C2H5OH) and nitrogen dioxide (NO2) at different temperatures were analyzed. The sensor showed a higher response toward C2H5OH than NO2 gas at 350 °C.