The limited kinetic energy of holes in AlGaN-based deep ultraviolet
light-emitting diodes (DUV LEDs) poses a challenge in their
transportation into the active region across the Al-rich electron
blocking layer (EBL) and significantly restricts the electrical and
optical performance of DUV LEDs. In this work, we propose a hole
accelerator structure composing a
p-AlxGa1-xN/n-AlxGa1-xN
junction to improve the hole injection efficiency and explore the
mechanism behind the enhanced performance with the Advanced Physical
Models of Semiconductor Devices software (APSYS). The built-in
electric field of the p-n junction distributes along the [000-1]
direction, which can enhance the hole drift velocity and improve the
hole injection into the active region. Moreover, with an optimum Al
composition of 50%, [000-1] oriented polarization-induced
electric field can be generated at the vicinity of both the
p-EBL/accelerator and accelerator/hole supplier interfaces, which
further boosts the holes into the active region. Besides, the original
steep barrier for holes at the EBL/hole supplier interface can be
splited into a two-step barrier which is more favorable for hole
transportation. As a result, an enhanced optical power by 49.4%
and alleviated efficiency droop by 76.3% can be achieved with
the proposed p-n junction-based hole accelerator. The results can pave
the way for AlGaN-based DUV LEDs towards high-power and
high-efficiency applications.