Giant photoresponse in p-type sodium-doped ZnO films

The detection of ultraviolet radiation is currently a topic that deserves the attention of society. This research shows that the addition of sodium (Na) to ZnO thin films enhances the generation and collection of photo- generated carriers at room temperature, making ZnO:Na a promising candidate for photosensors. This effect is particularly pronounced at 10 % Na-concentration, with a photoresponse around 104, 4 , suggesting a decrease in the role of deep traps. Additionally, as a defect engineering approach, annealing in different controlled atmospheres shows that the N2 2 atmosphere provides a markedly faster photoresponse. By introducing Na atoms into the ZnO crystal lattice, charge compensation levels are formed, inducing the p-type conductivity in some ranges of temperature, particularly at 300 K. Annealing in controlled atmospheres also influences both the transition from n-type to p-type conductivity and light-stimulated phenomena.