Surface-plasmon-enhanced GaN-LED based on a multilayered M-shaped nano-grating.

A multilayered metallic M-shaped nano-grating is proposed to enhance the internal quantum efficiency, light extraction efficiency and surface-plasmon (SP) extraction efficiency of the gallium nitride-based light emitting diodes. This structure is fabricated by the low-cost nano-imprint lithography. The suitable grating based on quasi-symmetrical-waveguide structure has a high transmission in the visible region. The properties of SP mode and the Purcell effect in this type of LED is investigated. The experimental results demonstrate that its peak photoluminescence intensity of the proposed LED is over 10 times greater than that from a naked GaN-LED without any nanostructure.