title: Enhancement of the evanescent wave coupling effect in a sub-wavelength-sized GaAs/AlGaAs ridge structure by low-refractive-index surface layers.
abstract: 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.
authors.forename: Xue-Lun
authors.initials: XL
authors.lastname: Wang
authors.forename: Guo-Dong
authors.initials: GD
authors.lastname: Hao
authors.forename: Tokio
authors.initials: T
authors.lastname: Takahashi
mesh_terms: D000535:Aluminum / Q000737:chemistry; D001152:Arsenicals / Q000737:chemistry; D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005708:Gallium / Q000737:chemistry; D008027:Light; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D008956:Models, Chemical; D055096:Optical Devices; D010316:Particle Size; D012031:Refractometry / Q000295:instrumentation*; D012542:Scattering, Radiation; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
chemical_list: D001152:Arsenicals; C043055:gallium arsenide; D005708:Gallium; D000535:Aluminum