INVESTIGATION OF LASER PRODUCED NOBLE METAL-SEMICONDUCTOR NANOSTRUCTURES

The ZnO/noble metal (both individually - Ag or Pd and in combination) nanocomposites are prepared by laser synthesis methods at atmospheric pressure in air. The formation of complex porous nanostructures is carried out by picosecond pulsed laser deposition at room temperature. The effect of post-deposition nanosecond laser annealing on the morphology and optical properties of the nanostructures is studied. The contribution of laser modifications to the change of a surface plasmon resonance (SPR) absorption band, and respectively, to the near-band-edge (NBE) and deep-level photoluminescence emission (DL), is investigated. The resonance absorption properties are obtainedfor Ag/ZnO nanostructures before and after the laser annealing. While the SPR absorption band appears for mono- and bimetallic samples with palladium after the laser annealing. The plasmon resonance absorption contributes to the enhancement of photoluminescence band-edge UV emission of all samples and suppression of the strong Vis DL emission of monometallic noble metal/ZnO nanocomposites after the annealing. The low level of the DLE emission is observed before the annealing of the bimetallic sample Ag-Pd/ZnO, with annealing slightly affecting it. This sample demonstrates significantly smaller nanoparticles (NPs), as well as a narrower size distribution in comparison to monometallic noble metal/ZnO nanocomposites.