Open AccessEfficiency improvement of a vertical light-emitting diode through surface plasmon coupling and grating scattering
Author(s) -
Chun-Han Lin,
Chieh Hsieh,
Charng-Gan Tu,
YaoHaur Kuo,
Horng-Shyang Chen,
Pei-Ying Shih,
CheHao Liao,
YeanWoei Kiang,
C. C. Yang,
Cheng-Wei Lai,
Guan-Ru He,
Jui-Hung Yeh,
Ta-Cheng Hsu
Publication year - 2014
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.22.00a842
Subject(s) - materials science , grating , optics , optoelectronics , surface plasmon , surface plasmon polariton , localized surface plasmon , surface plasmon resonance , plasmon , nanoparticle , physics , nanotechnology
The enhancement of output intensity, the generation of polarized output, and the reduction of the efficiency droop effect in a surface plasmon (SP) coupled vertical light-emitting diode (LED) with an Ag nano-grating structure located between the p-GaN layer and the wafer bonding metal for inducing SP coupling with the InGaN/GaN quantum wells (QWs) are demonstrated. In fabricating the vertical LED, the patterned sapphire substrate is removed with a photoelectrochemical liftoff technique. Based on the reflection measurement from the metal grating structure and the numerical simulation result, it is found that the localized surface plasmon (LSP) resonance induced around the metal grating crest plays the major role in the SP-QW coupling process although a hybrid mode of LSP and surface plasmon polariton can be generated in the coupling process. By adding a surface grating structure to the SP-coupled vertical LED on the n-GaN side, the output intensity is further enhanced, the output polarization ratio is further increased, and the efficiency droop effect is further suppressed.