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Proceedings Paper

Improvement of efficiency droop in resonance tunneling LEDs
Author(s): Chaowang Liu; Wang N. Wang; Philip A. Shields; Somyod Denchitcharoen; Federica Causa; Duncan E. W. Allsopp
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Paper Abstract

A resonance tunnelling LED structure having a high efficiency, low droop and negligible wavelength shift with current is reported in this study. The LED structure contains a thick InGaN bottom spacer between an n-GaN contact layer and a multiple quantum well (MQW) active region, and a thin InGaN top spacer between the MQW and an AlGaN electron blocking layer (EBL). The observed high efficiency and negligible wavelength shift with applied current are attributed to the thick InGaN bottom spacer that nucleates V-pits and acts as a strain control layer for the MQW. The thick InGaN layer also provides an electron reservoir for efficient electron tunnelling injection into the MQW and reduces the electropotential difference between the n-emitter and the p-emitter, to suppress current leakage at high driving current and reduce droop. The top InGaN spacer was designed to act as a magnesium back-diffusion barrier and strain relief layer from EBL so as to obtain high efficiency.

Paper Details

Date Published: 2 September 2008
PDF: 8 pages
Proc. SPIE 7058, Eighth International Conference on Solid State Lighting, 70580D (2 September 2008); doi: 10.1117/12.801322
Show Author Affiliations
Chaowang Liu, Univ. of Bath (United Kingdom)
Wang N. Wang, Univ. of Bath (United Kingdom)
Philip A. Shields, Univ. of Bath (United Kingdom)
Somyod Denchitcharoen, Univ. of Bath (United Kingdom)
Federica Causa, Univ. of Bath (United Kingdom)
Duncan E. W. Allsopp, Univ. of Bath (United Kingdom)

Published in SPIE Proceedings Vol. 7058:
Eighth International Conference on Solid State Lighting
Ian T. Ferguson; Tsunemasa Taguchi; Ian E. Ashdown; Seong-Ju Park, Editor(s)

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