Optical-luminescence properties of ZnO and TiO 2 nanopowders obtained by pulsed laser reactive ablation

The ZnO and TiO 2 nanopowders have been prepared by means of the pulsed laser reactive ablation of metallic (Zn, Ti) targets. The Structural, optical, and luminescent studies have been done using by X-ray diffractometry, electron microscopy, transmission, Raman and photoluminescent spectroscopy. All nanopowders having high optical transmission in the visible and near-IR regions of the spectrum. Based on the phonon mode analysis in the Raman spectrum of nanopowders the character of the quality of the crystal structure are determined and its evolution in the process of laser annealing. It was found that pulsed laser annealing makes it possible to significantly modify the luminescent properties of nanopowders by changing its intrinsic defective structure. Dependence of the photoluminescence intensity on excitation wavelength have been studied and the optimal wavelengths to excitation the luminescence were established.