InGaN light-emitting diode stripes with reduced luminous exitance

Area of Science:

• Optoelectronics
• Semiconductor devices
• Solid-state lighting

Background:

• Indium Gallium Nitride (InGaN) light-emitting diodes (LEDs) are crucial for modern lighting.
• Optimizing light extraction efficiency and thermal management is key for LED performance.
• Current LED chip designs may limit light spreading and increase junction temperatures.

Purpose of the Study:

• To demonstrate InGaN LEDs with stripe geometries and partially-inclined sidewalls.
• To investigate the impact of 3D chip shaping on light extraction efficiency and junction temperature.
• To assess the suitability of these enhanced LEDs for various lighting applications.

Main Methods:

• Fabrication of InGaN LEDs with stripe geometries.
• Laser-micromachining of chip sidewalls to create partially-inclined surfaces.
• Measurement and simulation (ray-trace) of light extraction efficiency.
• Analysis of junction temperature reduction and emission area increase.

Main Results:

• Demonstration of stripe geometry InGaN LEDs with enhanced light spreading.
• Light extraction efficiency increased by approximately 12% (8% via simulation).
• Reduction in junction temperatures observed due to improved light extraction.
• Effective emission area increased fourfold compared to cubic chips.

Conclusions:

• 3D chip geometries, specifically stripe designs with inclined sidewalls, significantly enhance LED performance.
• The improved efficiency and reduced thermal load make these LEDs highly suitable for general lighting.
• This advancement offers a pathway to more efficient and effective solid-state lighting solutions.