標題: Efficiency droop behavior improvement through barrier thickness modification for GaN-on-silicon light-emitting diodes
作者: Tzou, An-Jye
Lin, Bing-Cheng
Lee, Chia-Yu
Lin, Da-Wei
Liao, Yu-Kuang
Li, Zhen-Yu
Chi, Gou-Chung
Kuo, Hao-Chung
Chang, Chun-Yen
電子物理學系
光電工程學系
Department of Electrophysics
Department of Photonics
關鍵字: light-emitting diodes;GaN-on-Si;droop behavior improvement;thin barrier;external quantum efficiency
公開日期: 5-三月-2015
摘要: Crack-free GaN-based light-emitting diodes (LEDs) were grown on 150-mm-diameter Si substrates by using low-pressure metal-organic chemical vapor deposition. The relationship between the LED devices and the thickness of quantum barriers (QBs) was investigated. The crystal quality and surface cracking of GaN-on-Si were greatly improved by an AlxGa1-xN buffer layer composed of graded Al. The threading dislocation density of the GaN-on-Si LEDs was reduced to < 7 x 10(8) cm(-2), yielding LEDs with high internal quantum efficiency. Simulation results indicated that reducing the QB thickness improved the carrier injection rate and distribution, thereby improving the droop behavior of the LEDs. LEDs featuring 6-nm-thick QBs exhibited the lowest droop behavior. However, the experimental results showed an unanticipated phenomenon, namely that the peak external quantum efficiency (EQE) and light output power (LOP) gradually decreased with a decreasing QB thickness. In other words, the GaN-on-Si LEDs with 8-nm-thick QBs exhibited low droop behavior and yielded a good peak EQE and LOP, achieving a 22.9% efficiency droop and 54.6% EQE. (C) 2015 Society of Photo-Optical Instrumentation Engineers (SPIE)
URI: http://dx.doi.org/10.1117/1.JPE.5.057604
http://hdl.handle.net/11536/124710
ISSN: 1947-7988
DOI: 10.1117/1.JPE.5.057604
期刊: JOURNAL OF PHOTONICS FOR ENERGY
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