ZnO tetrapods-based humidity sensors

ZnO tetrapods were synthesized by an “environmentally green” microwave evaporation of Zn powder in air atmosphere, without any use of organic solvents or precursors. The tetrapods were characterized by X-ray diffractometry and Field Emission-Scanning Electron Microscopy. The ZnO powder was then deposited onto a commercial alumina substrate with interdigitated platinum electrodes and the sensitivity towards humidity was investigated at room temperature. Results showed a significant response from 30% relative humidity values and that the sensors were insensitive to N2O and methane.