ABSTRACT
The phenomenon of surface plasmon (SP) coupling with a light emitter and its application to light-emitting didoes (LEDs) in the visible range is reviewed and the details of SP coupling in the deep-UV range with Al nanostructures are discussed. First, the fundamental principles of SP coupling with a light emitter for enhancing its emission efficiency are explained. For the application to an LED, several useful metal nanostructures for inducing SP coupling with its quantum wells (QWs) are introduced. Then, the effects of SP coupling in an LED for improving its operation functions, including enhancing internal quantum efficiency (IQE), reducing efficiency droop, and increasing modulation bandwidth, are elucidated. Next, we focus the discussion on the SP coupling in the deep-UV range with Al nanostructures. The IQE enhancement of deep-UV AlxGa1−xN/AlyGa1−yN (x < y) QWs is shown by fabricating surface Al nanoparticles on a QW structure through thermally annealing an Al thin film for inducing SP coupling. Through temperature-dependent photoluminescence measurement, the enhancements of IQE in different emission polarizations are illustrated.
