On the p-AlGaN/n-AlGaN/p-AlGaN Current Spreading Layer for AlGaN-based Deep Ultraviolet Light-Emitting Diodes.

ABSTRACT

In this report, AlGaN-based deep ultraviolet light-emitting diodes (DUV LEDs) with different p-AlGaN/n-AlGaN/p-AlGaN (PNP-AlGaN) structured current spreading layers have been described and investigated. According to our results, the adopted PNP-AlGaN structure can induce an energy barrier in the hole injection layer that can modulate the lateral current distribution. We also find that the current spreading effect can be strongly affected by the thickness, the doping concentration, the PNP loop, and the AlN composition for the inserted n-AlGaN layer. Therefore, if the PNP-AlGaN structure is properly designed, the forward voltage, the external quantum efficiency, the optical power, and the wall-plug efficiency for the proposed DUV LEDs can be significantly improved as compared with the conventional DUV LED without the PNP-AlGaN structure.