Using Nitrogen Rapid Thermal Annealing to Enhance The Growth of Zinc Oxide Nanorods on p-GaN Substrate
| Autor: | Hong-Jhih Lin, 林宏治 |
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| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 106 In order to overcome the lattice mismatch of about 1.8% between ZnO nanorods and GaN substrate, the use of a thin ZnO seed layer has been reported by the majority of the literature. The quality of ZnO seed layer certainly then affected the overall luminous efficiency of the ZnO nanorods prepared. In this study, we used a hydrothermal method to deposit ZnO nanorods on p-GaN subtrate without the ZnO seed layer but with an annealing treatment of the GaN substrate. Although it is difficult to directly deposit ZnO nanorods on GaN substrate, we found that the use of rapid thermal annealing (RTA) pretreatment of the GaN substrate could help to successfully deposit ZnO nanorods on p-GaN substrate. A mixed solution of different compositions of zinc acetate (Zn(CH3COO)2‧H2O) and hexamethylenetetramine (C6H12N4) was used to deposit ZnO nanorods. To find the optimal temperature for RTA, we varied the RTA temperature but fixed the deposition time and temperature and then compared the corresponding results obtained. A scanning electron microscope (SEM) was used to identify the crystal structure of zinc oxide and surface morphologies. Moreover, the photoluminescence (PL) spectroscopy showed both a sharp ultraviolet band dominated by the free exciton and a broad visible band originated from defects. The experimental results demonstrated that the RTA pretreatment of p-GaN subtrate is critical to achieve good quality ZnO nanorods on top. An RTA temperature of 500℃ could present a strong UV band with the visible band being suppressed. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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