The method of coating near-ultraviolet light with phosphor powders is one of the main trends in the current development of white light-emitting diodes (LEDs). It a long time for the development of Ce3+ doped phosphor materials. The Ce3+ has one outer 4f1 electron. And this electron can be excited to 5d. The luminescence wavelength of Ce3+ doped phosphor materials different from the different host lattice.
First part of this paper is about the growth of cerium doped LiGaO2 crystal by conventional Czochralski melt pulling method. The dose of cerium is 0.2ppm. The growth were operated in the ambient pressure, with the pull rate of 2.0 mm/hour and the rotation rate of 10~20 RPM. LiGaO2 crystal of 200 mm in length was grown under these conditions. We found a yellow to green peak on 505 nm from the measurement of photoluminescence spectra. It showed that LiGaO2 can emit phosphorescence by the doped of cerium.
Second part of this paper is growth of Gallium nitride (GaN) thin films. GaN possess vast application potential in the fields of optoelectronics and microelectronics for its wide band gap, high thermal stability and high chemistry stability. GaN mostly grow on large lattice mismatch substrates, for the difficulty growth of GaN bulk single crystal and scarce of lattice match heteroepitaxial substrates. This result in great dislocation defects density in the GaN films. To lower the dislocation density of GaN films and improve the crystal quality is an important point of GaN research fields.
In this study, the GaN thin films were grown on £^-LiAlO2(100) substrates by Chemical Vapor Deposition(CVD). We found that the growth direction and structure of GaN were influenced by growth parameter. The GaN¡]10-10¡^ thin films were grown by the adjust of growth temperature and pressure.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0907107-113602 |
| Date | 07 September 2007 |
| Creators | Wei, Cheng-hong |
| Contributors | Jih-Jen Wu, Ming-Chi Chou, Liuwen Chang |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0907107-113602 |
| Rights | not_available, Copyright information available at source archive |
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