Highly c -axis textured ZnO thin films grown by electrochemical deposition and their optical properties

ZnO thin films were electrodeposited on glasses coated with a transparent-conductive film (InSnO) with different deposition currents. We have studied the dependence of microstructure, morphology and photoluminescence (PL) on the deposition current by X-ray diffraction, scanning electron microscopy and PL measurement at room temperature. We found that all the films show highly c -axis textured structure and the surface morphology is strongly current-dependent. The transmission spectra show that the films have a transmittance higher than 80% in the visible range. The films have an increase in thickness with the deposition current. The PL spectra exhibit two emission bands, an ultraviolet (UV) one from the exciton transition and a visible light one that might emerge from the defects in the films. The UV emission band has an obvious blueshift, which is found to be due to in doping during the deposition. With the increase of deposition current, the UV emission decreases while the visible light emission goes up.