We report a dramatic increase in the photoluminescence (PL) emitted from InGaN/GaN quantum wells (QW), obtained by covering these sample surface with thin metallic films. Remarkable enhancements of PL peak intensities were obtained from In0.3Ga0.7N QWs with 50 nm thick silver and aluminum coating with 10 nm GaN spacer. These PL enhancements can be attributed to strong interaction between QWs and surface plasmons (SPs). No such enhancements were obtained from samples coated with gold, as its well-known plasmon resonance occurs only at longer wavelengths. We also showed that QW-SP coupling increase the internal quantum efficiencies by measuring the temperature dependence of PL intensities. QW-SP coupling is a very promising method for developing the super bright light emitting diodes (LEDs). Moreover, we found that the metal nano-structure is very important facto to decide the light extraction. A possible mechanism of QW-SP coupling and emission enhancement has been developed, and high-speed and efficient light emission is predicted for optically as well as electrically pumped light emitters.
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Koichi Okamoto ; Isamu Niki ; Alexander Shvartser ; George Maltezos ; Yukio Narukawa, et al.
Surface plasmon enhanced InGaN light emitter
", Proc. SPIE 5733, Photonic Crystal Materials and Devices III, 94 (April 13, 2005); doi:10.1117/12.592261; http://dx.doi.org/10.1117/12.592261