Self-Assembled Size-Tunable Microlight-Emitting Diodes Using Multiple Sapphire Nanomembranes.

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Devices

Background:

• Micro-light-emitting diodes (Micro-LEDs) are crucial for future high-performance displays.
• Current Micro-LED commercialization faces hurdles like etching loss, reduced efficiency, high costs, and lengthy transfer processes due to singulation.

Purpose of the Study:

• To develop a novel technology for Micro-LED fabrication and transfer that overcomes existing commercialization barriers.
• To demonstrate a singulation-free process for producing Micro-LED arrays with improved performance.

Main Methods:

• Developed multiple-sapphire nanomembrane (MSNM) technology for Micro-LED fabrication.
• Utilized pendeo-epitaxy and coalescence of GaN on spaced SNMs to form individual Micro-LEDs.
• Fabricated Micro-LEDs of various sizes (20x20 μm², 40x40 μm², 100x100 μm²) using the MSNM membrane design.

Main Results:

• Successfully fabricated Micro-LEDs without a singulation procedure, enabling rapid array transfer.
• The 100x100 μm² Micro-LEDs showed an 80.6% stress relief and a 58.7% reduction in threading dislocation density compared to reference samples.
• Demonstrated successful transfer of MSNM Micro-LED arrays of varied chip sizes to a backplane and fabrication of a vertical structure LED with low operation voltage.

Conclusions:

• MSNM technology offers a promising pathway for the commercialization of Micro-LED technology by simplifying fabrication and enhancing device performance.
• The developed method effectively reduces defects and stress, leading to improved Micro-LED characteristics.
• This approach facilitates the production of high-quality Micro-LEDs for next-generation displays.