High Performance Of Algan Deep-Ultraviolet Light Emitting Diodes Due To Improved Vertical Carrier Transport By Delta-Accelerating Quantum Barriers

AlGaN-based deep-ultraviolet light emitting diodes adopting an embedded delta-AlGaN thin layer with an Al composition higher than that in conventional barriers have been investigated. The experimental result shows that when the current is below 250 mA, the maximum of the external quantum efficiency and light output power for the proposed structure reach severally 1.38% and 10.1 mW, which are enhanced significantly by 160% and 197%, respectively, compared to the conventional ones, showing a tremendous improvement. We attribute that to the inserted delta-thin layer's modulation effect on the energy band, namely, accelerating holes to cross the high barrier with very large kinetic energy, thus increasing the hole injection into the active regions. Meanwhile, the electron concentration within the active regions is enhanced as well because of the accompanying additional effect of the delta-AlGaN thin layer being an electron barrier to block electrons escaping from the active region. Published under license by AIP Publishing.