Open AccessLight outcoupling effect in GaN light-emitting diodes via convex microstructures monolithically fabricated on sapphire substrate
Author(s) -
Tae Su Oh,
Hyun Jeong,
Yong Seok Lee,
Ah Hyun Park,
Tae Hoon Seo,
Hun Kim,
Kang Jea Lee,
Mun Seok Jeong,
Eun Kyung Suh
Publication year - 2011
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.19.009385
Subject(s) - optics , light emitting diode , materials science , sapphire , optoelectronics , substrate (aquarium) , electroluminescence , diode , laser , physics , layer (electronics) , oceanography , composite material , geology
GaN-based light-emitting diode (LED) was fabricated on the sapphire substrate with monolithic convex microstructures (CMs) array. Using confocal scanning electroluminescence (EL), we have directly observed the strong outcoupling phenomenon of the light confined in a LED via the CMs array. This outcoupled light could be efficiently converged on the convex center through consecutive reflections at the flat area and the curved slant area of the CMs array. Compared to the conventional LED, the ray tracing simulation and far field EL results of the LED with a CM array showed efficient light extraction toward the top surface, i.e., 0-5, 40-45 and 60-65 degree by the outcoupling effect. We conclude that the outcoupled optical path via CMs is the dominant factor of the enhanced light extraction in the LED with a CM array.