The diffusion of Ag in GaN-based surface plasmon light-emitting diodes under different temperature annealing

In order to achieve effective coupling between the surface plasmon and the quantum wells (QWs) for surface plasmon LEDs, metal-embedded or thin p-GaN layer approach have been normally been used, but by taking either of these methods, the enhancement of the IQE of the fabricated SP-LEDs is not remarkable, in some cases, the internal quantum efficiency even decreases. Here, this study is to clarify the origin and understand what kind of influence of temperature treatment to the LED structure. GaN based LEDs with Ag from the same epitaxial wafer were annealed under different temperatures to imitate the high temperature treatment during the SP-LED fabrication. The results show that the diffusion of Ag into the quantum wells could be one of the reasons and in order to realize SP-LEDs with high IQE, high temperature treatments need to be avoided to prevent the diffusion of metal.