Near-Infrared Light Emissions from Er-doped ZnO Thin Films Induced by an Electrical Field

We obtained near-infrared (NIR) emissions by applying an electric field to a ZnO thin film containing Er ions. The sample construction was indium tin oxide (ITO) film/Er-doped ZnO film/ITO film on a SiO2 glass substrate. By applying a suitable alternative voltage to the sample, a broad luminescence in the NIR wavelength range was observed. The intensity of the luminescence increased with applied voltage. The luminescence induced by the electric field had a wavelength of 1.5 μm, which suggests that the light emission is related to the intrashell transition of Er3+.