1. Improvement of photon extraction efficiency of GaN-based LED using micro and nano complex polymer structures
- Author
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Jinseung Kim, Joong Yeon Cho, Kyeong Jae Byeon, Heon Lee, Hyeong Seok Kim, and Hyoungwon Park
- Subjects
Total internal reflection ,Materials science ,Nanostructure ,Nano Express ,High-refractive-index polymer ,Nanotechnology ,Electroluminescence ,Condensed Matter Physics ,Nanoimprint lithography ,law.invention ,Materials Science(all) ,law ,lcsh:TA401-492 ,General Materials Science ,lcsh:Materials of engineering and construction. Mechanics of materials ,Reactive-ion etching ,Plasma processing ,Refractive index - 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.
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