Improved emission of GaN-LED based on the optimized multilayered lamellar micro-gratings

We propose a type of GaN-LED based on the optimized multilayered lamellar micro-grating. This structure contains a SiO2 inserted-layer, an Ag grating and a TiO2 film cover-layer. The Ag grating with optimized parameters is used to enhance the internal quantum efficiency and the transmission simultaneously. The TiO2 layer with optimized thickness is utilized to improve the transmission through the multilayered structure. The inserted SiO2 layer suppresses the power loss of Ag grating and further promotes the transmission. The properties of the guided-modes and Purcell effect in this structure are analyzed. The photoluminescence experiment indicates that its peak intensity of top-emission is about 2.2 times greater than the naked sample.