Enhancement of light extraction efficiency by evanescent wave coupling effect in ridge-shaped AlGaInP/GaInP quantum wells

Abstract

The optical properties of a sub-wavelength-sized ridge-shaped AlGaInP/GaInP quantum well structure fabricated by selective-area metal organic vapor phase epitaxy are investigated. The ridge structure exhibits an 8.5 times stronger photoluminescence intensity at room temperature than a planar structure, corresponding to an enhancement of at least 13.6 times in the light extraction efficiency of the ridge sample with respect to the planar sample. Both emission pattern measurements and theoretical simulation demonstrate that the high light extraction efficiency originates from the evanescent wave coupling effect in a narrow ridge structure, which can directly extract the light outside the escape cones to air. © 2012 American Institute of Physics.