Sub-nanometer ultrathin epitaxy of AlGaN and its application in efficient doping

Area of Science:

• Materials Science
• Semiconductor Physics
• Solid State Chemistry

Background:

• Doping asymmetry in wide-gap semiconductors, particularly p-type doping in Al-rich AlGaN, hinders device applications.
• Achieving high hole concentrations and efficient carrier transport remains a significant challenge.

Purpose of the Study:

• To develop a novel strategy for overcoming the p-doping limitations in Al-rich AlGaN.
• To improve carrier concentration and transport properties for enhanced device performance.

Main Methods:

• A desorption-tailoring strategy was employed to prepare self-assembled p-AlGaN superlattices.
• Modulation of the Mg activation path and surface incorporation were key techniques.
• Fabrication of 280 nm deep-ultraviolet light-emitting diodes (DUV LEDs) for demonstration.

Main Results:

• Achieved a hole concentration of 8.1 × 10^18 cm^-3 at room temperature.
• Reduced effective Mg activation energy to 17.5 meV.
• Verified vertical miniband transport of holes due to constant ultrathin barrier thickness.
• Demonstrated a 55.7% increase in light output power for DUV LEDs.

Conclusions:

• The desorption-tailoring strategy effectively solves the p-type doping challenge in Al-rich AlGaN.
• This approach significantly enhances carrier injection and light extraction efficiency in DUV LEDs.
• The findings offer a general solution for doping asymmetry in wide-gap semiconductors.