The group III nitride semiconductor grown on c-plane sapphire by radio frequency plasma assisted molecular beam epitaxy has been studied. To archive good quality GaN thin film, nitridation and low temperature AlN buffer layer were applied to overcome the issue of lattice mismatch. Low temperature and long period nitridation process shows better improved of optical properties and crystal quality of GaN film. Buffer layer grown with slightly Ga-rich, substrate temperature at 600¢J, for 20 minutes leads to better GaN thin film. High substrate temperature and sufficient nitrogen to gallium ratio are two important factors to control the growth of the good quality GaN epilayer.
We have grown M-plane GaN films with self-assembled c-plane GaN nanopillars on a £^-LiAlO2 substrate by plasma-assisted molecular-beam epitaxy. The diameters of the basal plane of the nanopillars are about 200 to 900 nm and the height is up to 600 nm. The formation of self-assembled c-plane GaN nanopillars is through nucleation on hexagonal anionic bases of £^- LiAlO2. Dislocation defects were observed and analyzed by transmission electron microscopy. From the experimental results, we developed a mechanism underlying the simultaneous growth of three-dimensional c-plane nanopillars and two dimensional M-plane films on a £^-LiAlO2 substrate.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0826109-165237 |
| Date | 26 August 2009 |
| Creators | Hsieh, Chia-Ho |
| Contributors | Der shin Gan, I-Kai Lo, H. L. Huang, Ming-Chi Chou, Wei-Hung Su, Ken Hsieh |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0826109-165237 |
| Rights | campus_withheld, Copyright information available at source archive |
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