In recent years, even though the light output of GaN-related LED continues to increase, the brightness is still low compared to conventional lighting systems and it is necessary to further improve the light extraction of LEDs.
In this study, we utilize the ZnO nanotip with aqueous solution and flip-chip
technique to increase the light extraction of GaN LEDs. Electroluminescence (EL) and angular optical distribution are used to measure the light output intensity of LED.
In the results, ZnO nanotip after thermal annealing with N2O ambiance decrease the ZnO defects. Flip-chip LED has higher light intensity ( 1.25 times) than conventional one in vertical emitting area ( at 0 angles). The enhancement of light output is duo to the reduction of light absorption from the metal contact and Fresnel¡¦s transmission losses.
Finally, we fabricate a high brightness LED with above light enhancement design. EL intensity of LED is increased about 1.38 times than conventional one. Therefore, we can manufacture a LEDs array with above designs to obtain high light output for future solid-state illumination.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0802110-142406 |
| Date | 02 August 2010 |
| Creators | Lin, Jia-chi |
| Contributors | Jeng Gong, Ming-Kwei Lee, Yu-Hao Yang, Wen-Tai Lin |
| 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-0802110-142406 |
| Rights | not_available, Copyright information available at source archive |
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