Electrochemical Deposition ZnO Thin Film on High Sheet Resistance ITO Glass Substrate

ZnO thin films were electrochemically deposited onto an indium tin oxide(ITO)glass substrate with a high sheet-resistance of 118 Ω/□ from an electrolyte consisted of 0.1 mL Zn(NO3)2 aqueous solution at 65±1 ℃.The surface morphology of the ZnO thin films was characterized by scanning electron microscope(SEM)and the results showed that the hexagonal structure on the ZnO thin films gradually become obvious with the increasing of the deposition time or reducing of cathode potential.X-ray diffraction(XRD)was used to analyze the effect of cathode potential and deposition time on preferred orientation of the ZnO thin film.It showed that(002)preferred orientation of the ZnO thin film decrease with reducing the potential and increasing the deposition.Optical transmittance spectra of the ZnO thin films showed the obtained ZnO films are transparent to visible light and the average optical transmittance values of ZnO thin films were about 80 %～90%.In addition,the bandgap energy which was independent of the applied cathode potential was about 3.5 eV,while it would shift towards low values as the deposition time increased at an applied cathode potential of-2.5 V.