Surface plasmon mediated emission from metal/ZnO: an example for the fabrication of high brightness top-emitting light emitting diodes

摘要

In this study, we have attempted to enhance the forward emission from metal-capped ZnO mediated by surface plasmon (SP) cross coupling. By using metal alloys and dielectric grating, it is proposed that energy from ZnO can be resonantly coupled to metal/ZnO SPs, transferred to metal/grating SPs and then Bragg scattered to the free space. Although the experimental conditions are not yet been optimized, preliminary results from Al (30 nm) capped ZnO thin film show the forward/backward emission intensity ratio can be increased from 0.1 to 0.6 after the introduction of dielectric grating with periodicity of ～ 800nm on metal side. The ratio is compared favorably with the bare ZnO emission ratio of 0.5. It is thus believed SP cross coupling can be used for fabricating high brightness top-emitting light emitting diodes (LEDs).