Nano Structure Of Zno Electrochemical Deposition Of Tio <sub> 2 </ Sub> Thin Film On Its Optical Properties,

In this paper, well-aligned ZnO nanorod arrays have been successfully fabricated directly on anatase TiO2 nanoparticle films through a simple electrochemical deposition (ECD) method in the zinc nitrate solution. The samples were characterized by the methods of XRD, SEM, EDS, Raman and PL. The effects of the reactant concentration, deposition time, HMT additive and the microstructure of TiO2 film on the growth and the optical capability of the nanostructured ZnO obtained were studied in detail. The mechanism of ECD process was investigated by electrochemical methods such as cyclic voltammogram.Nanosized anatase TiO2 film on the ITO glass has been fabricated via spin coat process, with TiO2 nanoparticles, which were synthesized by a sol–hydrothermal method. It had uniform structure, composed of spherical nanoparticles with 10 nm in diameter. With ITO/TiO2 film as substrate, 0.03 mol/L Zn(NO3)2 solution acted as electrolyte and Zn sources, we could obtain nanostructured ZnO film when deposition potential was -0.75 V. ZnO crystal prepared by electrodeposition was hexagonal phase and grew along [002] direction (c-axis) with obvious preferential orientation, so as to form ZnO nanorod arrays vertically on the substrate. Although ZnO crystals were not passed through thermal treatment, its crystallinity was still quite high.Through altering deposition time, reactant concentration, microstructure of TiO2 film and adding functional molecule, we could regulate the crystallinity and surface morphology of ZnO film conveniently. The results showed that prolonging the deposition time, increasing the reactant concentration and adding a certain amount of HMT could promote the growth of ZnO film and increase crystallinity and orientation of nanorods, which is close related to the increase of depositon reagent OHˉconcentration in the ECD process. Compared with ITO glass substrate, ZnO could be more easily deposited on the TiO2 film, and the microstructure of film substrate had a great effect on the growth of ZnO.Under the excitation wavelength of 325 nm, the as-prepared compound semiconductor film exhibited a strong and narrow near-ultraviolet PL peak located at about 375 nm and a weak and broad green emission band centered at 520 nm around, mainly assigned to the photoluminescence of ZnO. Ultraviolet emission peak is attributed to the exciton-related emission near the band-edge and green emission band is attributed to the intrinsic defects of ZnO generally. Through adjusting and controlling the crystallinity of ZnO and the microstructure of ZnO nanorods array, the photoluminescence performance of the composite film could be changed.