Strategically constructed AlGaN doping barriers for efficient deep ultraviolet light-emitting diodes

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Conventional silicon (Si)-doping in AlGaN quantum barriers (QBs) for deep ultraviolet light-emitting diodes (DUV-LEDs) faces reliability challenges.
• Increased Si-doping levels in uniform QB structures can lead to performance degradation, including higher reverse leakage current (IR) and reduced light output power (LOP).

Purpose of the Study:

• To introduce and validate a sandwich-like Si-doping scheme (undoped/Si-doped/undoped) in AlGaN QBs.
• To simultaneously improve the optoelectronic performance and operational reliability of DUV-LEDs.

Main Methods:

• Experimental characterization using transmission electron microscopy (TEM).
• Numerical simulations to analyze carrier distribution and device performance.
• Fabrication and testing of DUV-LEDs with the proposed doping structure and conventional uniform doping.

Main Results:

• The proposed sandwich-like doping structure demonstrates improved interfacial quality within the multiple quantum wells (MQWs).
• More uniform carrier distribution was observed in the MQWs compared to uniform doping.
• DUV-LEDs with the proposed structure exhibited a superior wall-plug efficiency of 4%, a significant reduction in IR, and enhanced LOP stability after stress testing.

Conclusions:

• The sandwich-like Si-doping scheme effectively addresses the reliability issues associated with conventional doping in DUV-LEDs.
• This doping strategy offers a promising pathway for developing high-efficiency, cost-competitive, and reliable DUV-LEDs.