| Presentation | 2017-12-15 [Invited Talk] Recent progress of AlGaN deep-UV LEDs Hideki Hirayama, Masafumi Jo, Noritoshi Maeda, Yukio Kashima, |
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| PDF Download Page |  PDF download Page Link |
| Abstract(in Japanese) | (See Japanese page) |
| Abstract(in English) | AlGaN deep ultraviolet light-emitting diodes (DUV-LEDs) are attracting a great deal of attention, since they have the potential to be used in a wide variety of applications, such as for sterilization, water purification, UV curing, and in the medical and biochemistry fields, and so on. As a result of recent developments in AlGaN DUV LEDs, high internal quantum efficiencies (IQE) of more than 60-70 % have been achieved by reducing the threading dislocation density (TDD) of the AlN, by improving the crystal growth technique and/or by the introduction of AlN single crystal wafers. However, the wall-plug efficiency (WPE) of AlGaN DUV-LEDs still remains at several percent. The first target for the efficiency of AlGaN DUV-LEDs is to go beyond an efficiency of 20%, which would make them comparable to mercury lamps. A significant problem is that the light-extraction efficiency (LEE) of AlGaN DUV-LEDs is still quite low because of heavy UV absorption through the p-GaN contact-layer. Clearly, improving the LEE is a major topic in the development of AlGaN DUV-LEDs. Transparent contact layers and highly reflective electrodes are considered to be necessary in order to obtain sufficiently high LEEs in DUV LEDs. In this work, we demonstrate a record EQE ever reported of over 20% in an AlGaN DUV-LED by using a transparent p-AlGaN contact layer and a highly reflective p-type electrode to improve the LEE. We also demonstrated a record WPE of 10.8% in a DUV LED by suppressing the applying voltage reducing the contact resistance of p-AlGaN/reflective electrode. |
| Keyword(in Japanese) | (See Japanese page) |
| Keyword(in English) | deep-UV LEDAlNAlGaNMOCVDthreading dislocation densitywall plug efficiency |
| Paper # | LQE2017-91 |
| Date of Issue | 2017-12-08 (LQE) |
| Conference Information | |
| Committee | LQE |
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| Conference Date | 2017/12/15(1days) |
| Place (in Japanese) | (See Japanese page) |
| Place (in English) | |
| Topics (in Japanese) | (See Japanese page) |
| Topics (in English) | |
| Chair | Tsuyoshi Yamamoto(Fujitsu Labs.) |
| Vice Chair | Kiichi Hamamoto(Kyusyu Univ.) |
| Secretary | Kiichi Hamamoto(Tohoku Univ.) |
| Assistant | Yasumasa Kawakita(Furukawa Electric Industries) / Naoki Fujiwara(NTT) |
| Paper Information | |
| Registration To | Technical Committee on Lasers and Quantum Electronics |
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| Language | ENG |
| Title (in Japanese) | (See Japanese page) |
| Sub Title (in Japanese) | (See Japanese page) |
| Title (in English) | [Invited Talk] Recent progress of AlGaN deep-UV LEDs |
| Sub Title (in English) | |
| Keyword(1) | deep-UV LEDAlNAlGaNMOCVDthreading dislocation densitywall plug efficiency |
| 1st Author's Name | Hideki Hirayama |
| 1st Author's Affiliation | RIKEN(RIKEN) |
| 2nd Author's Name | Masafumi Jo |
| 2nd Author's Affiliation | RIKEN(RIKEN) |
| 3rd Author's Name | Noritoshi Maeda |
| 3rd Author's Affiliation | RIKEN(RIKEN) |
| 4th Author's Name | Yukio Kashima |
| 4th Author's Affiliation | Marubun(Marubun) |
| Date | 2017-12-15 |
| Paper # | LQE2017-91 |
| Volume (vol) | vol.117 |
| Number (no) | LQE-358 |
| Page | pp.pp.21-26(LQE), |
| #Pages | 6 |
| Date of Issue | 2017-12-08 (LQE) |