Highly Efficient Deep-UV Light-Emitting Diodes Using AlN-Based Deep-UV-Transparent Glass Electrodes.

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Developing transparent and conductive electrodes is challenging due to conflicting material properties.
• Existing solutions often fail to meet requirements for deep ultraviolet (DUV) applications.

Purpose of the Study:

• To propose and validate a novel AlN-based transparent electrode film.
• To achieve high transparency in the DUV region and low contact resistance.
• To demonstrate the electrode's performance in a DUV light-emitting diode (LED).

Main Methods:

• Fabrication of an AlN-based glass electrode film using AC pulse treatment.
• Characterization of optical transmittance and electrical contact resistance.
• Analysis of the Ohmic conduction mechanism at the AlN/p-AlGaN interface.
• Integration of the electrode into a 280 nm top-emitting LED.

Main Results:

• The AlN film achieved over 95.6% transmittance at 280 nm.
• Low contact resistance of 3.2 × 10⁻² Ω·cm² with p-Al₀.₄Ga₀.₆N was obtained.
• The fabricated 280 nm LED showed stable operation with a forward voltage of 7.7 V at 20 mA.
• A record external quantum efficiency of 2.8% was achieved after packaging.

Conclusions:

• The proposed AlN-based electrode film is a viable solution for transparent electrode applications in DUV optoelectronics.
• The AC pulse method effectively creates conductive filaments in AlN films.
• The developed electrode enhances the performance of DUV LEDs, particularly in terms of efficiency.