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Proceedings Paper

High modulation bandwidth of a light-emitting diode with surface plasmon coupling (Conference Presentation)
Author(s): Chun-Han Lin; Charng-Gan Tu; Yu-Feng Yao; Sheng-Hung Chen; Chia-Ying Su; Hao-Tsung Chen; Yean-Woei Kiang; Chih-Chung Yang

Paper Abstract

Besides lighting, LEDs can be used for indoor data transmission. Therefore, a large modulation bandwidth becomes an important target in the development of visible LED. In this regard, enhancing the radiative recombination rate of carriers in the quantum wells of an LED is a useful method since the modulation bandwidth of an LED is related to the carrier decay rate besides the device RC time constant To increase the carrier decay rate in an LED without sacrificing its output power, the technique of surface plasmon (SP) coupling in an LED is useful. In this paper, the increases of modulation bandwidth by reducing mesa size, decreasing active layer thickness, and inducing SP coupling in blue- and green-emitting LEDs are illustrated. The results are demonstrated by comparing three different LED surface structures, including bare p-type surface, GaZnO current spreading layer, and Ag nanoparticles (NPs) for inducing SP coupling. In a single-quantum-well, blue-emitting LED with a circular mesa of 10 microns in radius, SP coupling results in a modulation bandwidth of 528.8 MHz, which is believed to be the record-high level. A smaller RC time constant can lead to a higher modulation bandwidth. However, when the RC time constant is smaller than ~0.2 ns, its effect on modulation bandwidth saturates. The dependencies of modulation bandwidth on injected current density and carrier decay time confirm that the modulation bandwidth is essentially inversely proportional to a time constant, which is inversely proportional to the square-root of carrier decay rate and injected current density.

Paper Details

Date Published: 20 April 2017
PDF: 1 pages
Proc. SPIE 10124, Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XXI, 101240M (20 April 2017); doi: 10.1117/12.2249539
Show Author Affiliations
Chun-Han Lin, National Taiwan Univ. (Taiwan)
Charng-Gan Tu, National Taiwan Univ. (Taiwan)
Yu-Feng Yao, National Taiwan Univ. (Taiwan)
Sheng-Hung Chen, National Taiwan Univ. (Taiwan)
Chia-Ying Su, National Taiwan Univ. (Taiwan)
Hao-Tsung Chen, National Taiwan Univ. (Taiwan)
Yean-Woei Kiang, National Taiwan Univ. (Taiwan)
Chih-Chung Yang, National Taiwan Univ. (Taiwan)

Published in SPIE Proceedings Vol. 10124:
Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XXI
Jong Kyu Kim; Michael R. Krames; Li-Wei Tu; Martin Strassburg, Editor(s)

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