Monolithically integrated white light LEDs on (11-22) semi-polar GaN templates

Area of Science:

• Solid State Physics
• Materials Science
• Optoelectronics

Background:

• Carrier transport is critical for efficient light emission in LEDs.
• Semi-polar (11-22) Gallium Nitride (GaN) based LEDs offer unique properties for optoelectronic applications.
• Achieving stable white light emission in LEDs requires precise control over multiple emission colors.

Purpose of the Study:

• To investigate carrier transport issues in (11-22) semi-polar GaN based white LEDs.
• To determine the optimal growth order of yellow and blue Indium Gallium Nitride (InGaN) quantum wells for white light emission.
• To analyze the impact of a GaN spacer on hole concentration distribution and emission intensity.

Main Methods:

• Detailed device simulations were performed.
• Band diagrams and hole concentration distributions were analyzed.
• Monolithic multi-color LEDs were grown on semi-polar (11-22) GaN templates.

Main Results:

• The growth order of InGaN quantum wells significantly impacts white emission.
• A yellow InGaN quantum well followed by a blue InGaN quantum well is optimal.
• A thin GaN spacer effectively balances hole concentration between quantum wells.
• The spacer influences the relative intensity of yellow and blue emissions.

Conclusions:

• The growth sequence of InGaN quantum wells is critical for white LEDs.
• A thin GaN spacer is essential for balancing carrier distribution and achieving desired white light emission.
• This study demonstrates a method for fabricating high-quality multi-color LEDs on semi-polar GaN.