Title :
Photonic crystal structure effect on the enhancement in the external quantum efficiency of a red LED
Author :
Kim, Taesung ; Leisher, Paul O. ; Danner, Aaron J. ; Wirth, Ralph ; Streubel, Klaus ; Choquette, Kent D.
Author_Institution :
Univ. of Illinois Urbana-Champaign, Urbana, IL
Abstract :
The enhancement in external quantum efficiency of a red light-emitting diode (LED) from photonic crystal (PhC) hole patterns was investigated. A red LED was chosen because its epitaxial layers are relatively free from defects as compared to GaN-based LEDs. The peak emission wavelength was 642 nm, and a triangular-lattice PhC was designed with a hole diameter to lattice distance ratio of 0.5. The lattice distance to wavelength ratio (a/lambda) was varied from 0.2 to 4.6 in order to evaluate the enhancement in the external quantum efficiency. An improvement in efficiency greater than 75% was obtained for a/lambda between 0.6 and 2.0. This improvement of the optical characteristics occurred with unchanged electrical properties
Keywords :
light emitting diodes; optical design techniques; photonic crystals; external quantum efficiency; lattice distance ratio; photonic crystal; red LED; Epitaxial layers; Flat panel displays; LED lamps; Lattices; Light emitting diodes; Manufacturing; Photonic crystals; Rough surfaces; Surface morphology; Surface roughness; Light-emitting diode (LED); photonic crystal (PhC);
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2006.881235
