PhD. of Danae Delbeke
|Ontwerp en realisatie van een hoogefficiënte lichtemitterende diode: de resonante caviteitsdiode met diffractief rooster
|Design and fabrication of a highly efficient light-emitting diode: The Grating-Assisted Resonant-Cavity Light-Emitting Diode
Due to the typically large refractive index of the material in which spontaneous emission happens, the extraction efficiency of a standard Light Emitting Diode (LED) is limited to about 2 to 3 percent. Cancelling the isotropic internal emission profile by incorporation of a cavity –the so called Resonant Cavity LED (RCLED)- enhances the extraction efficiency to about 28%. In a cavity, interferences force the emitted photons in several discrete modes: the extractable Fabry-Perot mode and the unextractable lateral guided mode.
This PhD investigates the possibilities of a diffraction grating to extract the light emitted in the lateral guided mode in a RCLED. Theoretical investigation of dipole emission in a 2D periodically modulated multilayer predicts efficiencies up to 40%. Experimental evidence of this Grating Assisted RCLED shows an extraction efficiency as high as 35%.
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