High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light-emitting diodes exhibiting >50% external quantum efficiency
1999; American Institute of Physics; Volume: 75; Issue: 16 Linguagem: Inglês
10.1063/1.125016
ISSN1520-8842
AutoresMichael R. Krames, Mari Ochiai-Holcomb, G. E. Höfler, C. Carter-Coman, E. I. Chen, I.-H. Tan, P. N. Grillot, Nathan F. Gardner, H. C. Chui, James Huang, S. A. Stockman, F. A. Kish, M. G. Craford, Tun S. Tan, Chris Kocot, M. R. Hueschen, J. Posselt, B. Loh, G.E. Sasser, D. M. Collins,
Tópico(s)Semiconductor materials and devices
ResumoA 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 (λp∼610 nm) devices, with a peak luminous flux of 60 lumens (350 mA dc, 300 K). In the red wavelength regime (λp∼650 nm), peak external quantum efficiencies of 55% and 60.9% are measured under direct current and pulsed operation, respectively (100 mA, 300 K).
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