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Silver nanoparticles are being developed for applications in plasmonics, catalysts and analytical methods, amongst others. Herein, we demonstrate the growth of silver nanoparticles using an atomic layer deposition (ALD) process for the first time. The silver was deposited from pulses of the organometallic precursor (hfac)Ag(1,5-COD) ((hexafluoroacetylacetonato)silver(I)(1,5-cyclooctadiene)) dissolved in a 0.1 M toluene solution. Catalytic oxidative dehydrogenation of the silver was achieved using intermittent pulses of propanol. The effect of substrate temperature on the size and distribution of nanoparticles has been investigated over the temperature range 110-150 degrees C. Transmission electron microscopy reveals that the nanoparticles consist of face centred cubic, facetted silver crystallites. The localized surface plasmon modes of the nanoparticles have been investigated using electron energy loss spectroscopy mapping. The distributions of plasmons within the ALD nanoparticles are comparable to those grown by solution methods. Both dipolar and quadrupolar resonant modes are observed, which is consistent with previous discrete dipole approximation models. Energy loss mapping of a loss feature at 8.1 eV reveals that it correlates with the bulk or volume region of the silver nanoparticles investigated here.

The optical properties of zinc oxide nanowires are critically influenced by the growth process. Herein, we describe a metal-organic chemical vapour deposition (MOCVD) process for the growth of ZnO nanowires with improved optical properties. A tetrahydrofuran adduct is used to control the reactivity of dimethylzinc to enable this. Vertically aligned zinc oxide nanowires have been grown on Si(111) substrates by liquid injection MOCVD, using a solution of [Me(2)Zn(tetrahydrofuran)] in the presence of oxygen. The ZnO morphology becomes nanowire-like in a narrow temperature range centred about 500 degrees C. Above and below this temperature range, the ZnO is deposited in the form of polycrystalline films. The ZnO nanowires grow from a polycrystalline nucleation layer, with the (0002) c-axis parallel to the Si[111] substrate orientation. High-resolution electron microscopy reveals a highly crystalline nanowire microstructure. Resonance enhanced ultraviolet Raman spectroscopy shows that the ratio of first- and second-order longitudinal optic modes is commensurate with electron-phonon coupling effects observed previously in ZnO nanostructures. Photoluminescence exhibits intense near band-edge emission with a full width at half-maximum of 110 meV at room temperature and shows negligible defect-related visible emission.