Applied Physics Express · 2010 · 81 citations · 27 references
EngineeringElectrical EngineeringMaterials ScienceMicroelectronicsSemiconductor DevicesSemiconductor MaterialsLight-emitting DiodesOptoelectronic DevicesOptoelectronic MaterialsSemiconductor PhysicsWide Band Gap SemiconductorsWide-bandgap SemiconductorsBlue Light-emitting DiodesExternal Quantum EfficiencyExtraction EfficiencyGallium Nitride (Gan) MaterialsLight ExtractionLight Extraction EfficiencyPower OutputQuantum Efficiency
The first 30-mW-class semipolar blue light-emitting diode (LED) on a free-standing (10) GaN substrate has been demonstrated by using microscale periodic backside structures. The light extraction efficiency and corresponding output power were greatly enhanced, by up to 2.8-fold (bare chip) compare with conventional devices. At a driving current of 20 mA, the LED showed an output power of 31.1 mW and an external quantum efficiency of 54.7%. Semipolar GaN LED technology is now comparable to commercial c-plane blue LED technology, not only in terms of internal material properties but also in terms of chip processing techniques.
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