Strongly directional emission from AlGaAs/GaAs light-emitting diodes

Abstract

We show for the first time that strongly directional emission of defined polarization can be achieved from conventional AlGaAs/GaAs double-heterostructure surface-emitting light-emitting diodes (LEDs) via coupling to surface plasmons. By microstructuring the surface, we have fabricated LEDs with a beam divergence of less than 4° and an increased quantum efficiency. It is demonstrated that the surface plasmon excitation and emission mechanism have the potential to improve the performance of LEDs.

Surface-plasmon enhanced bright emission from CdSe quantum-dot nanocrystals

“…Recently, 6 we reported a method for enhancing the light-emission efficiency from InGaN QWs by controlling the energy transfer between QWs and surface plasmons (SPs). The idea of SPenhanced light emission was previously described [7][8][9][10][11][12] and, for the first time (to our knowledge), we directly measured significant enhancement of internal quantum efficiency of emission due to spontaneous recombination rate increases. 6,13 We believe that this SP-enhanced technique can be applied not only to InGaN-based materials but also to various other materials.…”

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

“…This finding is very important since it shows that if one is to extract the power lost to the SPP modes of structures such as those considered here it is the SPP associated with the metal/organic interface upon which our attention should be focussed, not the SPP associated with the metal/air interface; it is this latter mode which has more frequently been investigated in the past. 15,16,19,20 We can extend the value of such calculations by integrating the area under each peak in the power dissipation spectrum. By so doing we can determine the power coupled to each mode as a fraction of the total power radiated by the emitter.…”

“…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.…”

Surface plasmon enhanced light-emitting diode

“…Many interesting approaches have been proposed to accomplish this, such as the use of thin light-emitting layers with surface texturing [1], resonant cavities [2], photon recycling [3], or output coupling through surface plasmons excited at corrugated metal surfaces [4]. External quantum efficiencies of 31% were reported by employing reflection from a bottom metal mirror together with a textured top semiconductor surface [5].…”