By sputtering a layer of 40 nm Ag film on ZnO microrods prepared by the aqueous solution method, we observed photoluminescence enhancement from ZnO microrods coated with Ag nanoparticles, comparing with pure ZnO microrods. The ratio of the enhancement, in particular, reaches 6.6 at 396 nm. The enhancement mechanism is attributed to the special distribution of the silver nanoparticle film, which is helpful for efficiently coupling the energy of electron-hole pairs in ZnO microrods to the local surface plasmons (LSP) of silver particles and scattering the energy of LSP into free space as a form of radiated light.Recently, ZnO has attracted great attention for semiconductor optoelectronic device and ultraviolet (UV) laser device use, due to its wide and direct bandgap of 3.36 eV at room temperature and higher exaction binding energy (60 meV) [1-3], comparing to ZnSe (22 meV), ZnS (40 meV), and GaN (25 meV). But there are also some shortcomings of ZnO, such as the weak fluorescence and comparatively high excitation energy. In recent years, some research groups have concentrated on enhancement of the bandgap emission of ZnO by using the surface plasmons (SP) or localized surface plasmons (LSP) of various noble metals. Lai et al [4] and Ni et al [5] achieved 16-fold and 5.5-fold UV emission enhancement, separately, by coating the ZnO films with certain thicknesses of Al and Ag. You et al [6] sputtered ZnO film on Si(001) substrate which had already been coated with 100 nm Ag film previously, and the UV emission of the composite is found to be greatly enhanced. Cheng et al [7] also have shown 3-fold enhancement of bandgap emission of ZnO by coating the film with a layer of Ag island film.However, the ZnO samples mentioned above are all prepared by RF magnetron sputtering, which imposes high demands on the equipment and the technological parameters

Highly ordered silicon nanorod (SiNR) arrays with controllable geometry are fabricated via nanosphere lithography and metal-assisted chemical etching. It is demonstrated that the key to achieving a high-quality metal mask is to construct a non-close-packed template that can be removed with negligible damage to the mask. Hydrophobicity of SiNR arrays of different geometries is also studied. It is shown that the nanorod structures are effectively quasi-hydrophobic with a contact angle as high as 142 • , which would be useful in self-cleaning nanorod-based device applications.

Ag/SiO2multilayers were prepared by RF magnetron sputtering. Via rapid thermal treatment, most of Ag nanoparticles move up to the surface. By changing the layer thickness of Ag and SiO2, Ag particles of different size, density and shape were obtained. The effect of factors such as size, density and shape of the Ag particle, on resonance absorption is also investigated. We change the annealing time according to the diffusion length. Ag particles with a facet parallel to substrate are obtained under adequate annealing time (17.5min). Since the atoms easily transport between particles within the facets, the radius of Ag particle decreases, and tends to a critical size. Correspondingly, the resonance absorption band becomes narrower and blueshift occurrs.

ZnO and ZnO/Ag films are grown on Si (111) substrates by rf magnetron sputtering at room temperature. After annealing, it is found that the ultraviolet (UV) emission of ZnO/Ag films strongly depends on the thickness of the initial internal Ag layer. During the annealing process, Ag nanoparticles are formed and diffused into the ZnO film. The resonant coupling between localized surface plasmons (LSPs) of Ag nanoparticles and ZnO enhances the UV emission. The largest UV enhancement over 12 times is found when the initial internal Ag layer is 10 nm. It is also observed that the diffusion of Ag nanoparticles destroys the ZnO crystal quality in different grades, depending on the sizes of the Ag nanoparticles. The poor crystal quality induces bad UV emission. It is concluded that the UV emission is the result of the competition between the LSP enhancement and the thermal diffusion destroying effect from Ag nanoparticles.

Well aligned ZnO nanowire arrays with high crystal quality were grown on Si substrates at a low temperature (50 degrees C) by hydrothermal method using a pre-formed ZnO seed layer. ZnO seeds were prepared via radio-frequency magnetron sputtering onto Si substrates. The morphologies of the ZnO nanowire arrays were shown by field emission scanning electron microscopy. X-ray diffraction spectra showed that the full width at the half maximum of the (0002) peak of the nanowire arrays without any heat treatment was only 0.07 degrees, indicating very high crystal quality. Furthermore, the room-temperature photoluminescence spectra of the ZnO nanowire arrays exhibited excellent UV emission. The special micro/nano surface structure of the ZnO nanowire arrays can enhance the dewettability for surfaces modified via low surface energy materials such as long chain fluorinated organic compounds. The surface of the ZnO nanowire arrays is also found to be superhydrophobic with a contact angle of 165 degrees +/- 1 degrees, while the sliding angle is 3 degrees.