| 학회 |
한국재료학회 |
| 학술대회 |
2016년 가을 (11/16 ~ 11/18, 경주 현대호텔) |
| 권호 |
22권 2호 |
| 발표분야 |
A. 전자/반도체 재료 분과 |
| 제목 |
Improved performance of AlGaN-based deep UV LED on nano-patterned substrate |
| 초록 |
AlGaN-based deep ultraviolet (DUV) light emitting diodes (LEDs) have attracted much attention due to their numerous applications such as water purification, sterilization, and curing. However, the external quantum efficiency of DUV LEDs is still very low due to both the low internal quantum efficiency (IQE) and the low light extraction efficiency (LEE). The low IQE is attributed to the high threading dislocation density in the AlGaN layer grown on a foreign substrate such as sapphire. The low LEE is originated most likely from strong DUV light absorption in the top p-GaN contact layer. To overcome these problems and to realize highly efficient DUV LEDs, it is essential to grow high quality AlGaN layers and to enhance the LEE. In this study, we proposed an incorporation of an embedded air-void photonic crystal (PhC) by the nanoscale epitaxial lateral overgrowth (ELO) of AlN on a nano-patterned substrate (NPS). In order to fabricate the embedded PhC, we formed periodic nanoscale patterns using nanosphere lithography and then ELO of AlN was performed on the patterns by metal-organic chemical vapor deposition. We could obtain a fully coalesced high quality AlN layer with a mirror-like smooth surface within a coalescence thickness of 3 μm at the growth temperature of 1050 oC. In addition, the air voids formed between the substrate and the overgrown AlN layer were found to effectively relax the tensile tress during the growth so that crack-free DUV LED wafers were obtained even tor a total thickness of 7.9 μ m. Furthermore, the light output power (LOP) of DUV LEDs grown on NPS was enhanced by 122% at an injection current of 20 mA compared to the reference DUV LEDs on a planar AlN/sapphire substrate. The significant enhancement of LOP was attributed to the improvement in both IQE by nanoscale ELO and LEE by the air-void PhC in the DUV LED structure. |
| 저자 |
이동현1, 이종원2, 장정환1, 신인수1, 김로1, 박준혁2, 김정섭3, 이진섭3, 노혜석3, 김용일3, 박영수3, 이건도1, 박용조4, 김종규2, 윤의준1
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| 소속 |
1서울대, 2포항공과대, 3삼성전자, 4차세대융합기술(연) |
| 키워드 |
<P>deep UV LED; AlN; nano-patterned substrate</P>
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| E-Mail |
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