Applied Physics Letters · 2014 · 117 citations · 16 references
EngineeringElectrical EngineeringMaterials ScienceOptoelectronicsSemiconductor DevicesSemiconductor MaterialsDopingLight SourcesLight-emitting DiodesLuminescent MaterialsQuantum WellsSemiconductor Device MaterialsCarrier InjectionCharge InjectionExternal Quantum EfficiencyLeakageLight-emitting DevicesQuantum EfficiencyQuantum Well HeterostructuresUltraviolet Light-emitting Diodes
The design and Mg-doping profile of AlN/Al0.7Ga0.3N electron blocking heterostructures (EBH) for AlGaN multiple quantum well (MQW) light emitting diodes (LEDs) emitting below 250 nm was investigated. By inserting an AlN electron blocking layer (EBL) into the EBH, we were able to increase the quantum well emission power and significantly reduce long wavelength parasitic luminescence. Furthermore, electron leakage was suppressed by optimizing the thickness of the AlN EBL while still maintaining sufficient hole injection. Ultraviolet (UV)-C LEDs with very low parasitic luminescence (7% of total emission power) and external quantum efficiencies of 0.19% at 246 nm have been realized. This concept was applied to AlGaN MQW LEDs emitting between 235 nm and 263 nm with external quantum efficiencies ranging from 0.002% to 0.93%. After processing, we were able to demonstrate an UV-C LED emitting at 234 nm with 14.5 μW integrated optical output power and an external quantum efficiency of 0.012% at 18.2 A/cm2.
16
Mg acceptor level in AlN probed by deep ultraviolet photoluminescence
K. B. Nam, M. L. Nakarmi, J. Li et al. · Applied Physics Letters · 2003 · 311 citations
Natural Sciences, Materials Engineering, Materials Science +15
Hideki Hirayama, Yusuke Tsukada, Tetsutoshi Maeda et al. · Applied Physics Express · 2010 · 297 citations