Surface plasmon enhanced light-emitting diode

Abstract

Abstract-A method for enhancing the emission properties of light-emitting diodes, by coupling to surface plasmons, is analyzed both theoretically and experimentally. The analyzed structure consists of a semiconductor emitter layer thinner than 2 sandwiched between two metal films. If a periodic pattern is defined in the top semitransparent metal layer by lithography, it is possible to efficiently couple out the light emitted from the semiconductor and to simultaneously enhance the spontaneous emission rate. For the analyzed designs, we theoretically estimate extraction efficiencies as high as 37% and Purcell factors of up to 4.5. We have experimentally measured photoluminescence intensities of up to 46 times higher in fabricated structures compared to unprocessed wafers. The increased light emission is due to an increase in the efficiency and an increase in the pumping intensity resulting from trapping of pump photons within the microcavity.

Electronic modulation of infrared radiation in graphene plasmonic resonators

“…As thermal radiation is a form of spontaneous emission, the emission rate is increased by the presence of the plasmonic cavity, with the degree of rate enhancement dictated by the ratio between the Q factor and mode volume of the optical cavity (that is, the Purcell factor) 41 . This effect has been explored as a means of increasing LED switching rates by placing the semiconductor emitting layer within either a plasmonic or photonic cavity [42][43][44][45][46] . For the case of graphene plasmonic nanoresonators that have highly confined mode volumes, the Purcell factor has been shown to be extremely high, approaching 10 7 , and, thus, the modulation rate of thermal emission from our device could be exceedingly fast, beyond what has been demonstrated with plasmonically enhanced LEDs or lasers 47 .…”

Plasmonics: Localization and guiding of electromagnetic energy in metal/dielectric structures

“…The huge increase of the non-radiative decay rate observed for emissive species placed in nanometric distances to metallic surfaces makes the design of plasmonic cavities for emissive devices challenging, 109 but promising routes for the creation of efficient emissive devices such as light-emmiting diodes ͑LEDs͒ based on SPPsupporting cavities have been developed 110,111 and partly demonstrated. 112 For dipolar emitters placed into the immediate vicinity of metallic surfaces, where the dielectric continuum model, on which a macroscopic description of the metal-emitter interaction is based, breaks down, a further order-of-magnitude increase in the nonradiative decay rates based on interactions with the unscreened electrons of the metal surface has been predicted, 113 which makes plasmonic devices of high promise for high-speed optical switching.…”

Light emission through a corrugated metal film: The role of cross-coupled surface plasmon polaritons

“…In the context of the work reported here the question of whether such enhanced transmission requires an array of holes or can be accomplished with just a periodically modulated film is of particular interest. 14 Several authors have explored the possibility of using periodically modulated metal films to extract light from surface plasmon polariton modes, [15][16][17][18][19][20] though only Gifford and Hall 6,21 have so far reported experimental results specifically to look at surface plasmon polariton cross coupling as a means of extracting light from such structures.…”