| | | Document Type | : | Latin Dissertation | | Language of Document | : | English | | Record Number | : | 52649 | | Doc. No | : | TL22603 | | Call number | : | 3218010 | | Main Entry | : | Muhammad Maqbool | | Title & Author | : | Growth, characterization and luminescence and optical properties of rare -earth elements and transition metals doped in wide bandgap nitride semiconductorsMuhammad Maqbool | | College | : | Ohio University | | Date | : | 2005 | | Degree | : | Ph.D. | | student score | : | 2005 | | Page No | : | 200 | | Abstract | : | Rare-earth element and transition metals doped AlN, GaN and BN films were successfully grown using reactive magnetron sputtering. The structural, optical and luminescence properties of these nitride films were then studied using Scanning Electron Microscopy, X-rays diffraction, Cathodoluminescence and Tube furnace. Both amorphous and crystalline films were obtained depending on the substrate temperature during the deposition. Cryogenically grown amorphous films were the principal focus of this research. The substrate were cooled using liquid nitrogen during the growth and pure amorphous films were obtained. Crystalline films were also obtained using an electric heater to keep substrates at high temperature. X-ray diffraction analysis was used to confirm the structure of films. Rare-earth elements Ho, Gd, Pr, Tm and Sm and transition metals W and Y were doped into the nitride films by co-sputtering. The optical and luminescence properties of these nitride materials were studied using Cathodoluminescence. Characteristic light emissions related to these Ho+3, Gd +3, Pr+3, Tm+3, Sm+3, W+3 and Y+3 ions were observed. The results show the suitability of these materials for potential applications of light-emitting devices. Luminescence enhancement in the nitride materials was studied by co-doping Gd with Ho, Pr, Sm and W in nitride materials. Stripes of these materials were also prepared and studied for luminescence enhancement. It was observed that not only the presence of Gd but also some interference phenomena enhance luminescence in these materials. More than 100% enhancement in luminescence shows that these techniques used for luminescence enhancement are successful and useful for future applications. Stopping power of AlN for electrons and depth penetration of electron were studied by making bilayers of AlN doped with Tm+3 and Ho+3 ions. Electron beams of different energies were allowed to penetrate in the known thickness of the AlN:Tm/AlN:Ho bilayer. Stopping power of AlN was calculated using the numerical values of the energies of electron beams and the thickness of the bilayers. | | Subject | : | Pure sciences; Luminescence; Nitride semiconductors; Rare earth; Transition metals; Wide-bandgap; Condensation; 0611:Condensation | | Added Entry | : | M. E. Kordesch | | Added Entry | : | Ohio University |
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