Current crowding effect for AlGaN based ultraviolet-B light-emitting diodes (UVB LEDs) is normally observed at high injection current levels, which can cause non-uniform optical emission and generate very high local heat. In this work, UVB LED with a PNP-AlGaN current spreading layer is fabricated and studied. The PNP-AlGaN current spreading layer is obtained by sandwiching the n-AlGaN layer into the p-AlGaN layer. Owing to the modulated energy band profiles by the different doing types, the formed energy barriers for holes in PNP-AlGaN layer can make the current more uniformly distributed laterally and therefore the hole injection efficiency at the mesa edges can be enhanced. As a result, the measured external quantum efficiency (EQE) and optical output power for the proposed UVB LED is increased. Moreover, thanks to the enhanced current spreading effect, the thermal droop for the optical output power is suppressed and the forward voltage decreases for the proposed architecture.

中文翻译：

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掺杂诱导能垒以改善基于 AlGaN 的紫外-B 发光二极管的电流扩展效果

通常在高注入电流水平下观察到基于 AlGaN 的紫外-B 发光二极管 (UVB LED) 的电流拥挤效应，这会导致不均匀的光发射并产生非常高的局部热量。在这项工作中，制造和研究了具有 PNP-AlGaN 电流扩展层的 UVB LED。PNP-AlGaN电流扩展层是通过将n-AlGaN层夹在p-AlGaN层中而获得的。由于不同类型的调制能带分布，在PNP-AlGaN层中形成的空穴能垒可以使电流横向分布更均匀，因此可以提高台面边缘的空穴注入效率。结果，增加了所提出的 UVB LED 的测量外部量子效率 (EQE) 和光输出功率。而且，