Authors
Michael R Krames, M Ochiai-Holcomb, GE Höfler, C Carter-Coman, EI Chen, I-H Tan, P Grillot, NF Gardner, HC Chui, J-W Huang, SA Stockman, FA Kish, MG Craford, TS Tan, CP Kocot, M Hueschen, J Posselt, B Loh, G Sasser, D Collins
Publication date
1999/10/18
Journal
Applied physics letters
Volume
75
Issue
16
Pages
2365-2367
Publisher
American Institute of Physics
Description
A truncated-inverted-pyramid (TIP) chip geometry provides substantial improvement in light extraction efficiency over conventional AlGaInP/GaP chips of the same active junction area (∼0.25 mm2). The TIP geometry decreases the mean photon path-length within the crystal, and thus reduces the effects of internal loss mechanisms. By combining this improved device geometry with high-efficiency multiwell active layers, record-level performance for visible-spectrum light-emitting diodes is achieved. Peak efficiencies exceeding 100 lm/W are demonstrated (100 mA dc, 300 K) for orange-emitting devices, with a peak luminous flux of 60 lumens (350 mA dc, 300 K). In the red wavelength regime peak external quantum efficiencies of 55% and 60.9% are measured under direct current and pulsed operation, respectively (100 mA, 300 K).
Total citations
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