Special Section on Solid-State Lighting: Photonics and Technologies

Efficiency droop behavior improvement through barrier thickness modification for GaN-on-silicon light-emitting diodes

[+] Author Affiliations
An-Jye Tzou, Yu-Kuang Liao

National Chiao Tung University, Department of Electrophysics, 1001 Ta Hsueh Road, Hsinchu 30010, Taiwan

National Chiao Tung University, Department of Photonics and Institute of Electro-Optical Engineering, 1001 Ta Hsueh Road, Hsinchu 30010, Taiwan

Bing-Cheng Lin, Chia-Yu Lee, Da-Wei Lin, Gou-Chung Chi, Hao-Chung Kuo

National Chiao Tung University, Department of Photonics and Institute of Electro-Optical Engineering, 1001 Ta Hsueh Road, Hsinchu 30010, Taiwan

Zhen-Yu Li

National Chiao Tung University, Department of Photonics and Institute of Electro-Optical Engineering, 1001 Ta Hsueh Road, Hsinchu 30010, Taiwan

Research Center for Applied Sciences, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11592, Taiwan

Chun-Yen Chang

National Chiao Tung University, Department of Electrophysics, 1001 Ta Hsueh Road, Hsinchu 30010, Taiwan

Research Center for Applied Sciences, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11592, Taiwan

J. Photon. Energy. 5(1), 057604 (Mar 05, 2015). doi:10.1117/1.JPE.5.057604
History: Received October 31, 2014; Accepted February 2, 2015
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Abstract.  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 AlxGa1xN buffer layer composed of graded Al. The threading dislocation density of the GaN-on-Si LEDs was reduced to <7×108cm2, 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.

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© 2015 Society of Photo-Optical Instrumentation Engineers

Citation

An-Jye Tzou ; Bing-Cheng Lin ; Chia-Yu Lee ; Da-Wei Lin ; Yu-Kuang Liao, et al.
"Efficiency droop behavior improvement through barrier thickness modification for GaN-on-silicon light-emitting diodes", J. Photon. Energy. 5(1), 057604 (Mar 05, 2015). ; http://dx.doi.org/10.1117/1.JPE.5.057604


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