AlGaN Polarized Ultrathin Tunneling Junction Deep Ultraviolet Light-Emitting Diodes

Area of Science:

• Optoelectronics
• Materials Science
• Semiconductor Physics

Background:

• Deep ultraviolet light-emitting diodes (DUV-LEDs) face challenges with optical losses and high operating voltages.
• These issues stem from p-contact layers, including light absorption in p-GaN and poor hole injection in p-AlGaN due to high acceptor ionization energy and AlGaN-based tunneling junctions (TJs) with high bulk resistance.

Purpose of the Study:

• To introduce an innovative transparent AlGaN polarized ultrathin tunneling junction (PUTJ) to overcome the limitations of current DUV-LEDs.
• To enhance hole injection efficiency and reduce electrical and optical losses in the p-contact layer of DUV-LEDs.

Main Methods:

• Designed and fabricated a novel transparent AlGaN polarized ultrathin tunneling junction (PUTJ).
• The PUTJ features ultrathin p- and n-regions (20 nm) and an intrinsic AlGaN interlayer utilizing polarized electric fields.
• Integrated the PUTJ into a 273 nm DUV-LED device.

Main Results:

• Achieved significantly reduced bulk resistance in the tunneling junction.
• The PUTJ design minimized optical absorption losses due to its reduced thickness.
• Demonstrated a record-low operating voltage of 5.8 V at 30 A/cm² for the 273 nm DUV-LED.

Conclusions:

• The transparent AlGaN PUTJ effectively enhances interband tunneling injection of holes.
• This advancement leads to substantial reductions in both optical and electrical losses in DUV-LEDs.
• The developed PUTJ technology represents a significant step towards highly efficient III-nitride optoelectronics and DUV light sources.