Properties And Morphology Of ZnO Nanorods Grown On It And ZnO/Ag/ZnO Mutilayers

ZnO/Ag/ZnO multilayer films with different Ag thickness were deposited by RF magnetron sputtering to study how the morphology and the size of the silver layer affect the optical transmittance enhancement and the photoluminescence enhancement. Field emission scanning electron microscope (FESEM), Atomic force microscope (AFM), X-ray diffraction (XRD), Transmittance, Photoluminescence (PL) are used to measure and analysis the structural, morphological and optical properties of ZnO/Ag/ZnO films. ZnO/Ag/ZnO sandwich structures obtained with optimized deposition conditions are used as a seed layer to grow ZnO array nanorods with various solution concentrations and decorated with Ag nanoparticles. Meanwhile, contrast experiments of a single ZnO with same thicknesses as a seed layer for the growth of ZnO array nanorods are also carried out. We study how seed layer’s structure, solution concentration and decorated Ag nanoparticles influence the morphological, hydrophobic and optical properties of ZnO nanorods using FESEM, PL, and water contact angle measurement.The results show that with the increase of Ag film thickness ranging from 3.2 nm to 22 nm there are obvious red shifts in surface plasmon resonance peaks, indicating that the surface plasmon resonance wavelength and optical broadening are associated with the morphology and size of Ag. A strong enhanced transmittance in optical wavelength range of 500-700 nm is observed for ZnO/Ag/ZnO multilayer films with Ag layer thickness of 3.2 nm. The strongest UV and VIS emissions of a certain ZnO/Ag/ZnO multilayer film with the silver thickness of about 10 nm are over five times and twenty times stronger than these of a pure ZnO single layer, respectively.ZnO array nanorods grown on the ZnO(30nm)/Ag(3.2nm)/ZnO(70nm) seed layer have the characteristics of higher density, more uniform size distribution, and more disorderly growth orientation that ZnO array nanorods grown on a single ZnO(100nm) seed layer. For ZnO nanorod array/ZnO grown in various solution concentrations there is a change from hydrophobic to hydrophilic property. ZnO array nanorods /ZAZ with the higher solution concentration of 75 mmol/L has a super hydrophobic property; and PL spectra of ZnO nanorod array/ZAZ with the appropriate solution concentration of 50 mmol/L have UV enhancement more than 3 times that of ZnO array nanorods/ZnO.