Thesis (M.Sc.) - Cairo University - National Institute of Laser Enhanced Sciences (NILES) - Department of Laser Sciences and Interactions

To attain UV stimulated emission, pure ZnO and Ag doped ZnO thin films of 0.005, 0.01, 0.02, 0.03, and 0.05 molar concentrations of Ag precursor were prepared by sol-gel spin coating process. Different preparation parameters were studied during fabrication, including precursor concentrations, aging time of solutions before deposition, number of layers, baking temperature and time, and annealing treatment conditions. Structural and morphological properties were studied by XRD and SEM measurements. XRD results showed that all the films are poly-crystalline with hexagonal wurtzite structure. SEM images revealed better homogeneity of Ag:ZnO films than pure films, with typical film thickness for all films of ~ 2.6 om. Photoluminescence measurements were done for all samples, which demonstrated the stimulated emission characteristics from pure ZnO films and Ag:ZnO films with doping concentration higher than 0.01M, with threshold pump intensities of ~ 23 MW.cm-2 and 18 MW.cm-2 for pure and doped thin films, respectively. The output-input relation for these samples showed a kink positioned at the mentioned threshold intensities. The stimulated emission mechanism and the role of Ag doping in the stimulated emission process were discussed. I-V characteristics were studied for both pure and Ag doped samples and the results were discussed

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