Efficient Semipolar (11-22) 550 nm Yellow/Green InGaN Light-Emitting Diodes on Low Defect Density (11-22)...

Area of Science:

• Semiconductor Physics
• Materials Science
• Optoelectronics

Background:

• Semipolar (11-22) InGaN light-emitting diodes (LEDs) offer potential for efficient light emission.
• Achieving high efficiency in longer wavelength LEDs remains a challenge due to material quality and efficiency droop.

Purpose of the Study:

• To demonstrate efficient semipolar (11-22) 550 nm yellow/green InGaN LEDs.
• To investigate the impact of InGaN barriers on LED performance.
• To assess the potential for large-area, economical production.

Main Methods:

• Fabrication of semipolar (11-22) InGaN LEDs on patterned sapphire templates.
• Utilizing In0.03Ga0.97N barriers.
• Characterization using atom probe tomography (APT).
• Performance testing including output power, external quantum efficiency (EQE), and current-dependent blue-shift.

Main Results:

• Demonstrated efficient 550 nm yellow/green InGaN LEDs with an output power of 2.4 mW at 100 mA.
• Achieved a peak external quantum efficiency (EQE) of 1.3% with a low efficiency drop.
• Atom probe tomography confirmed the presence of In0.03Ga0.97N barriers and absence of InGaN clusters.
• Observed a minimal blue-shift of 11 nm from 5 mA to 100 mA.

Conclusions:

• The developed semipolar (11-22) InGaN LEDs exhibit high efficiency and stable performance at longer wavelengths.
• The use of In0.03Ga0.97N barriers is effective in preventing InGaN clustering and improving device characteristics.
• These findings highlight the feasibility of producing high-efficiency, long-wavelength InGaN LEDs on large-area sapphire substrates cost-effectively.