Surface Plasmon Enhanced Solid-State Light-Emitting Devices

A novel method to enhance light emission efficiencies from solid-state materials was developed by the use of surface plasmon (SP). A 17-fold increase in the photoluminescence (PL) intensity along with a 7-fold increase in the internal quantum efficiency (IQE) of light emission from InGaN/GaN quantum wells (QWs) was obtained when nanostructured silver layers were deposited 10 nm above the QWs. A 32-fold increase in the spontaneous emission rate of InGaN/GaN at 440 nm probed by the time-resolved PL measurements was also observed. Likewise, both light emission intensities and rates were enhanced for organic materials, CdSe-based nanocrystals, and also Si/SiO2 nanostructures. These enhancements should be attributed to the SP coupling. Electron–hole pairs in the materials couple to electron vibrations at the metal surface and produce SPs instead of photons or phonons. This new path increases the spontaneous emission rate and the IQEs. The SP-emitter coupling technique would lead to super bright and high-speed solid-state light-emitting devices that offer realistic alternatives to conventional fluorescent light sources.