Moisture Sensing Application of ${\rm Cu}_{2}{\rm O}$ Doped ZnO Nanocomposites

Pellet samples of 2, 5, 10, 15, and 20 weight % of Cu₂Odoped ZnO nanocomposites have been prepared through solid-state reaction route. These samples have been annealed at temperatures 200°C-500°C and then exposed to humidity in a chamber. Resistance of the pellets continuously decreased when relative humidity in the chamber was increased from 10% to 90%. The sample with 20% of Cu₂O doped in ZnO showed best results with sensitivity of 4.78 MΩ/%RH for annealing temperature of 400°C. This sample manifests high reproducibility, less effect of aging and lower hysteresis for annealing temperature 400°. The response and recovery time of this sample is found to be 76 and 296 s, respectively. XRD pattern shows peaks of hexagonal zincite and monoclinic tenorite.