LASER SYNTHESIS AND PROCESSING OF COMPOSITE NANOSTRUCTURES

The present work reports the fabrication of porous composite ZnO/noble metal (Ag, Au) nanostructures using ps-pulsed laser deposition at atmospheric pressure. The PLD grown samples are ns-laser annealed, which led to a surface modification and formation of nanoparticles and NP’s aggregates. The effect of laser annealing procedure on the morphology, structure and optical properties of composite nanostructures is studied. The experimental results indicate that the laser annealing changes the plasmon resonance absorption mostly in the silver-doped samples. The laser modification plays a key role in tuning the PL performance for all samples by different mechanisms. Along with the increase in UV emission, there is a corresponding decrease in the broadband defect emission with the laser modification of composite nanostructures. The plasmon resonance absorption contributes to the enhancement of photoluminescence band-edge UV emission of the silver doped samples, while the PL performance of nanostructured ZnO/Au samples is attributed to the surface-plasmon-mediated sequential transfer of defect energy from ZnO to Au and electron transfer from excited Au to ZnO.