Research On Improving Characteristics Of LED Luminescence With Surface Plasmon Polariton

The problem of resources scarcity and environmental degradation is becoming worse and worse,so resource conservation and environmental protection have become an inevitable choice for Chinese sustained economic development.Semiconductor Light Emitting Diode?LED?is widely used in the fields of lighting,display and communication because of its advantages of environmental friendliness,long service life,high efficiency,high speed,and high reliability,which is far more than traditional light source.However,due to the inherent properties of the Group III nitride LED materials and the lack of manufacturing processes,the current LED luminous efficiency is not ideal,there is still huge room for improvement in performance.In this paper,we have innovatively combined media/metal nanostructures with surface plasmons,which have simultaneously improved Internal quantum efficiency and light extraction efficiency of GaN-based blue LED.All of this can provide some theoretical guidance in the future research.The main research contents are as follows:?1?The luminescent properties and research status of LED are mainly analyzed,and the reasons for the low LED luminous efficiency are discussed.Several feasible schemes for improving LED light extraction efficiency are introduced in detail.What's more,The basic principle,advantages and disadvantages are introduced.Then,the research progress and application fields of surface plasmon LED are introduced.?2?Then,we take p-n junction as a theoretical model to understand the basic principle of LED,which including radiative recombination and non-radiative recombination;LED light escape cone model and quantum efficiency.Here,we mainly present the concept of surface plasmons,basic properties,excitation mode and coupling mechanism of exciton and LED quantum well.?3?The finite element method which is a numerical simulation method commonly used in modern optical device analysis is applied in this design,and here,we present some simple derivation of its principle formula.We use COMSOL Multiphysics simulation software as numerical simulation,the use of software and parameter settings are mainly discussed in the paper and the dispersion model of metal materials is introduced,too.Subsequently,the material selection and structural design process of the LED model are introduced,so as to ensure the maximum luminous performance of LED.?4?The COMSOL Multiphysics simulation software is used to optimize the parameters of the silver film thickness,grating period,grating duty cycle and ITO buffer layer thickness in the LED structure.Then the SPP mode characteristics,Purcell effect,normalized radiation power and normalized absorption power are analyzed.The results show that the structure has a higher transmission efficiency in the visible range whose Purcell factor increased 16.4 times,luminous efficiency increased 9.514 times at a period of p=280 nm,a duty cycle of f=0.5,d_SiO2=25 nm,d_Ag=15 nm and d_ITO=30nm.