Applied Physics Letters · 2004 · 98 citations · 14 references
EngineeringElectrical EngineeringMaterials ScienceElectronic MaterialsOptoelectronicsSemiconductor DevicesDislocations In SemiconductorsLight SourcesLight-emitting DiodesQuantum WellsSemiconductor Device MaterialsWide-bandgap SemiconductorsBlue Light-emitting DiodesDislocationsHeat DissipationInternal Quantum EfficiencyLight-emitting DevicesPower OutputQuantum EfficiencyUltraviolet Light-emitting Diodes
Blue and near-ultraviolet (UV) InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs) with peak emission at 465 nm and 405 nm, respectively, were grown on GaN and sapphire substrates. The densities of surface and bulk defects in the homoepitaxially grown LEDs were substantially reduced, leading to a decrease in reverse currents by more than six orders of magnitude. At a typical operating current of 20 mA, the internal quantum efficiency of the UV LED on GaN was twice as high compared to the UV LED on sapphire, whereas the performance of the blue LEDs was found to be comparable. This suggests that the high-density dislocations are of greater influence on the light emission of the UV LEDs due to less In-related localization effects. At high injection currents, both the blue and UV LEDs on GaN exhibited much higher output power than the LEDs on sapphire as a result of improved heat dissipation and current spreading.
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S. J. Rosner, Elizabeth C. Carr, M. J. Ludowise et al. · Applied Physics Letters · 1997 · 530 citations
Natural Sciences, Materials Engineering, Materials Science +17