Investigation of spontaneous emission from quantum dots embedded in two-dimensional photonic-crystal slab

Investigated is spontaneous emission (SE) from quantum dots (QDs) embedded within a 2D, photonic crystal (PC) slab, from the viewpoint of redistribution of the excited carriers. SE lifetime was found to increase up to 15-fold, close to theoretically predicted value, by the 2D photonic-bandgap effect and 3D carrier confinement effect of QDs. Emission efficiency in the vertical direction was simultaneously increased 15-fold by excited-carrier redistribution. An artificial point-defect cavity introduced within the PC led to cavity-mode emission at extremely low excitation-power densities <0.4 W · cm^-2.