Open AccessEnhancement of the evanescent wave coupling effect in a sub-wavelength-sized GaAs/AlGaAs ridge structure by low-refractive-index surface layers
Author(s) -
XueLun Wang,
Guo-Dong Hao,
Tokio Takahashi
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.22.0a1559
Subject(s) - materials science , ridge , optics , refractive index , wavelength , facet (psychology) , photoluminescence , optoelectronics , semiconductor , coupling (piping) , gallium arsenide , physics , psychology , paleontology , social psychology , personality , big five personality traits , metallurgy , biology
We have investigated the three-dimensional emission patterns of GaAs/AlGaAs ridge structures with a sub-wavelength-sized top-flat facet by angle-resolved photoluminescence (PL). We found that the integrated PL intensity, and hence the light-extraction efficiency, can be enhanced by about 34% just by covering the ridge surface with a thin SiO2 layer. A double-coupling effect of evanescent waves that occurs at both the semiconductor-SiO2 and SiO2-air interfaces is suggested to be responsible for the improvement, based on a finite-difference time-domain simulation of the electromagnetic field around the ridge top.