| Green energy and sustainable development has become one of the most impotentissues for people in all of the world, The low-carbon economy themed as the green,environmental protection, energy saving and emission reduction has been become themajor melody of social economic development. Semiconductor Light Emitting Diodes(LEDs) present the advantages of environment friendliness, long lifetimes and the hugepotential of energy conservation, which attract considerable attention of scholars fromhome and abroad. However, the light extraction efficiency is still relatively low, thereforethe utilization of plasmon to improve the light extraction efficiency of LED has beenproposed, which has some practical and theoretical significance. The primary contentincludes:The basic principles, advantages, and disadvantages of currently several waves toimprove LED light extraction efficiency has been described in detail on the basis ofresearch on the development and current status of the LED light extraction efficiency.LED light emitting principle structure and luminescence properties were discussed;Plasmon concept, basic principles and the use of plasmons to improve the LED lightextraction efficiency were emphasized.In this paper, metal-metal double grating structure and metal-media double gratingstructure were established. Before we built these models, first, we described theoreticalanalysis of time domain finite difference method in detail, principle formulas were simplyderived. And then analyzed the specific parameters for numerical simulation of these twostructures by EastFDTD software, the specific choice of parameters and settings weredetermined, as well. Finally carried out a detailed analysis of the simulation results, whichverified the grating structure can excite metal surface plasmons, and improve the lightextraction efficiency of the LED. At a grating period of300nm and a silver film thicknessof30nm, light extraction efficiency reaches a maximum of0.44, which had increased18-fold and6-fold compared with less grating structure and single grating structurerespectively; At a grating period of365nm and a silver film thickness of390nm, light extraction efficiency reaches a maximum of0.53, this result compared with metal-metaldouble grating structure has improved9%. These numerical simulation analyses provide atheoretical basis for the progress of the LED light extraction efficiency. |
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