마이크로패턴된 그래핀 중간층을 매개로한 LED 선택성장기술을 이용하여, 금속전극상에 고밀도로 집적할 수 있는 마이크로-LED소자구현.
Realizing high-resolution integration of GaN micro-LEDs directly on metal electrodes using a micro-patterned graphene interlayer
The fabrication of optoelectronic devices on metal substrates is of great interest for applications including flexible LED displays and optoelectronics integrated with Si electronics. Since metals are highly conductive, both electrically and thermally, and when appropriately microstructured, can also be mechanically flexible, growing semiconductor heterostructures directly on metals can streamline the fabrication of thermally or mechanically-optimized optoelectronic devices. Nevertheless, previous efforts to grow high-quality inorganic films directly on metal electrodes faced challenges because of lack of epitaxial relations between semiconductor and metal, and large thermal expansion coefficient mismatches.
Here, high-quality GaN microdisk LEDs were fabricated on W metal electrodes using CVD graphene films as an intermediated layerbetween the GaN and substrates. Graphene plays a critical role in the growth of high-quality GaN microdisk arrays because graphene, with its hexagonal crystal structure of carbon atoms, can have an epitaxial relationship with wurtzite GaN crystals and can also tolerate epitaxial growth of GaN at high temperatures. Furthermore, the GaN microdisk array formed on reduced heterojunction area between graphene and GaN did not show any cracking and tearing in GaN. The micro-LEDs exhibited good electrical connectivity with W and were fully operational as a light-emitting array. These results offer fast, efficient and reliable pathways for realizing high-resolution and high-performance optoelectronic devices that can be integrated with various electronics.
Journal: Kunook Chung et al.,“GaN microstructure light-emitting diodes directly fabricated on tungsten-metal electrodes using a micro-patterned graphene interlayer”, Nano Energy 60, 82-86, (2019). [IF 15.548]