ZnO film growth with ZnO buffer layer by MOCVD
| Autor: | Chen-Wei Lu, 陸丞威 |
|---|---|
| Rok vydání: | 2010 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 98 In this research, high quality ZnO films without annealing were grown by MOCVD on sapphire (0001) substrates. ZnO films were grown by two step method, ZnO buffer layers were grown at 300℃ at first step, then ZnO main layers were grown subsequently at 350℃at second step. Using ZnO buffer layers grown at 300℃ can promote optical property and electron mobility of ZnO films. The dislocation density of ZnO films was decreased by increasing the thickness. When growth time was 2 hours, ZnO films with smooth surface, high preferred orientation and free from cracks were successfully obtained. Photoluminescence spectra showed strong near band edge emission. The improvement of optical property and electron mobility is attributed to significant improvement of crystal quality of ZnO films. TEM SAD pattern demonstrates that there are two crystallographic orientation relationships between the orientation of ZnO and sapphire at interface, 0ｏ and 30ｏ, respectively. The diffracted beams present arcs and not spots, representing that the orientation is not well-aligned at interface. However, spotty SAD pattern represent the structure away from interface is well crystallizd single crystal. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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