GaN-Based Light-Emitting Diodes on Micro-Lens Patterned Sapphire Substrate
| Autor: | Hyun Jeong, Gye Mo Yang, Tae Ki Kim, Seung-Hwan Kim, Tae Su Oh, Yong Seok Lee, Eun-Kyung Suh |
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| Rok vydání: | 2008 |
| Předmět: |
Microlens
Materials science Physics and Astronomy (miscellaneous) business.industry General Engineering General Physics and Astronomy law.invention law Optoelectronics Dry etching Metalorganic vapour phase epitaxy Inductively coupled plasma Photolithography Dislocation business Diode Light-emitting diode |
| Zdroj: | Japanese Journal of Applied Physics. 47:5333-5336 |
| ISSN: | 1347-4065 0021-4922 |
| DOI: | 10.1143/jjap.47.5333 |
| Popis: | GaN-based light-emitting diodes (LEDs) were fabricated on a micro-lens patterned sapphire substrate (ML-PSS). ML patterning on the sapphire substrate was carried out by using photolithography with photo-resist reflow technique and dry etching process using chlorine based inductively coupled plasma. The ML-PSS was prepared using a periodic ML pattern with diameters of 3 µm and spacing of 2, 4, and 5 µm, respectively, on the c-plane sapphire substrate. The leakage current of the LEDs fabricated on the ML-PSS greatly decreased compared to that of a conventional LED and it decreases with increasing ML-pattern spacing; it decreases from 1.8 to 0.2 µA at reverse voltage of 15 V as the ML-pattern spacing is increased from 2 to 5 µm. The output power of the LED with 5 µm spacing was about 155% higher than that of a conventional LED and about 10% higher than that of the LED on the PSS with spacing of 2 µm. This improvement of the output power is contributed not only by reduction of dislocation density depending on spacing of patterning but also by the enhancement of light extraction efficiency with outcoupling via the ML patterned facets on sapphire substrate. |
| Databáze: | OpenAIRE |
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