Applied Physics Letters · 2011 · 201 citations · 10 references
EngineeringElectrical EngineeringMaterials ScienceOptoelectronicsSemiconductor DevicesSemiconductor MaterialsDislocations In SemiconductorsLight SourcesLight-emitting DiodesOptoelectronic DevicesQuantum WellsSemiconductor Device MaterialsDislocation DensityGreen Light-emitting DiodesInternal Quantum EfficiencyLight ExtractionLight-emitting DevicesPhotoluminescenceQuantum EfficiencyQuantum Well Light-emitting Diodes
Green GaInN/GaN quantum well light-emitting diode (LED) wafers were grown on nanopatterned c-plane sapphire substrate by metal-organic vapor phase epitaxy. Without roughening the chip surface, such LEDs show triple the light output over structures on planar sapphire. By quantitative analysis the enhancement was attributed to both, enhanced generation efficiency and extraction. The spectral interference and emission patterns reveal a 58% enhanced light extraction while photoluminescence reveals a doubling of the internal quantum efficiency. The latter was attributed to a 44% lower threading dislocation density as observed in transmission electron microscopy. The partial light output power measured from the sapphire side of the unencapsulated nanopatterned substrate LED die reaches 5.2 mW at 525 nm at 100 mA compared to 1.8 mW in the reference LED.
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Isamu Akasaki Isamu Akasaki, Hiroshi Amano · Japanese Journal of Applied Physics · 1997 · 661 citations · Full text
Kazuyuki Tadatomo, Hiroaki Okagawa, Youichiro Ohuchi et al. · Japanese Journal of Applied Physics · 2001 · 376 citations