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Proceedings Paper

Improvement of hole injection efficiency for implementing thin p-type light-emitting diodes (Conference Presentation)
Author(s): Chia-Ying Su; Chun-Han Lin; Charng-Gan Tu; Yu-Feng Yao; Wei-Heng Liu; Hsin-Chun Chiang; Ming-Yen Su; Meng-Che Tsai; Huang-Hui Lin; Keng-Ping Chou; Hao-Tsung Chen; Shaobo Yang; Yean-Woei Kiang; Chih-Chung Yang

Paper Abstract

By increasing the Mg-doping level and hence the hole concentration in the p-AlGaN electron-blocking layer, the polarization field in this layer can be screened for reducing the potential barrier of hole and hence enhancing the hole tunneling efficiency such that the overall LED emission efficiency is increased. The increase of Mg-doping level is implemented based on an Mg pre-flow growth technique, in which Mg source is supplied into the metalorganic chemical vapor deposition chamber for several minutes before the growth of p-AlGaN or p-GaN. Based on a simulation study, we observe that the energy difference between the valence band-edge and the quasi-Fermi level of hole in the EBL is reduced by increasing the Mg-doping level in this layer such that the total hole density in the quantum wells is increased for enhancing the LED emission efficiency. Based on this technique, the high performance of an LED with the total p-type thickness as small as 38 nm is demonstrated. The surface plasmon coupling effects, including the enhancement of internal quantum efficiency, increase of output intensity, reduction of efficiency droop, and increase of modulation bandwidth, among the thin p-type LED samples of different p-type thicknesses are compared. These advantageous effects are stronger as the p-type layer becomes thinner. With a circular mesa size of 10 micron in radius, we achieve the record-high modulation bandwidth of 625.6 MHz among c-plane GaN-based LEDs.

Paper Details

Date Published: 14 March 2018
Proc. SPIE 10554, Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XXII, 1055407 (14 March 2018); doi: 10.1117/12.2286822
Show Author Affiliations
Chia-Ying Su, National Taiwan Univ. (Taiwan)
Chun-Han Lin, National Taiwan Univ. (Taiwan)
Charng-Gan Tu, National Taiwan Univ. (Taiwan)
Yu-Feng Yao, National Taiwan Univ. (Taiwan)
Wei-Heng Liu, National Taiwan Univ. (Taiwan)
Hsin-Chun Chiang, National Taiwan Univ. (Taiwan)
Ming-Yen Su, National Taiwan Univ. (Taiwan)
Meng-Che Tsai, National Taiwan Univ. (Taiwan)
Huang-Hui Lin, National Taiwan Univ. (Taiwan)
Keng-Ping Chou, National Taiwan Univ. (Taiwan)
Hao-Tsung Chen, National Taiwan Univ. (Taiwan)
Shaobo Yang, National Taiwan Univ. (Taiwan)
Yean-Woei Kiang, National Taiwan Univ. (Taiwan)
Chih-Chung Yang, National Taiwan Univ. (Taiwan)

Published in SPIE Proceedings Vol. 10554:
Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XXII
Jong Kyu Kim; Michael R. Krames; Martin Strassburg; Li-Wei Tu, Editor(s)

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