title: Improvement of photon extraction efficiency of GaN-based LED using micro and nano complex polymer structures.
abstract: A micro- and nanoscale complex structure made of a high refractive index polymer (n = 2.08) was formed on the ITO electrode layer of an edge-emitting type GaN blue light-emitting diode (LED), in order to improve the photon extraction efficiency by suppressing total internal reflection of photons. The nanoimprint lithography process was used to form the micro- and nanoscale complex structures, using a polymer resin with dispersed TiO2 nano-particles as an imprint resin. Plasma processing, such as reactive ion etching, was used to form the micro- and nano-scale complex structure; thus, plasma-induced damage to the LED device can be avoided. Due to the high refractive index polymeric micro- and nanostructure on the ITO layer, the electroluminescence emission was increased up to 20%, compared to an identical LED that was grown on a patterned sapphire substrate to improve photon extraction efficiency.
authors: Department of Materials Science and Engineering, Korea University, Anam-dong 5-ga, Seongbuk-gu, Seoul 136-713, South Korea. heonlee@korea.ac.kr.
authors: Joong-Yeon
authors: JY
authors: Cho
authors: Kyeong-Jae
authors: KJ
authors: Byeon
authors: Hyoungwon
authors: H
authors: Park
authors: Jinseung
authors: J
authors: Kim
authors: Hyeong-Seok
authors: HS
authors: Kim
authors: Heon
authors: H
authors: Lee