Structural Design Of Semiconductor To Improve Led Light Extraction Efficiency Based On Surface Plasmons

In recent years, Ga N-based LED development very quickly in LED family, it can be used to create a blue LED, together with red and green LED of other materials will be able to achieve full color display.Thus, the development potential of Ga N-based LED-related technology is enormous.However, due to the inherent properties of the semiconductor material, Ga N-based LED efficiency is not very good, there is still a huge space to improve performance.This article focuses on the use of current popular media/metal nanostructures and surface plasmon technology to improve the performance of Ga N-based LED.FDTD is used in the research which is commonly used in the modern optoelectronic devices analysis. Ga N-based LED model with various parameters is established. the impact of the media/metal nanostructures on Ga N LED performance is discussed and structure is optimized, theoretical support is provided for the development of new and efficient Ga N-based LED.The main contents include:1. On the basis of the development and research of the LED light extraction efficiency, the reason for the low efficiency of LED light was discussed, the basic principles, advantages, and disadvantages of currently several waves to improve LED light extraction efficiency were described in detail.2. The concept and development process of surface plasmon was introduced, electromagnetic properties of surface plasmons was analyzed. The basic properties of graphene and surface plasmon on graphene were described. The principle of using surface plasmons to improve LED light extraction efficiency was emphasized.3. Mixed-grating structure LED was established by etching two-dimensional grating on upper surface of silver and etching one-dimensional grating on under surface of silver. A numerical simulation was conducted using the finite difference time domain method(FDTD). The results showed that light extraction efficiency of LED has improved a lot with mixed-grating structure. The grating period, duty cycle, silver film thickness and light source depth have been optimized. Simulation results were as follows: When the grating period was 280 nm, duty cycle was 0.23, silver film thickness was 20 nm and light source depth was 20 nm, light extraction efficiency of double-grating structure was improved by 18 times than that with general structure. These results provided some references for practical high performance design and optimization of Ga N-LED.4. Graphene grating LED with graphene layer was inserted in Ga N and grating was etched on the surface is designed. In this structure, silver film was replaced by a grapheme layer to produce SP, and by this way, the light loss in the previous silver film can be avoided.The finite difference time domain(FDTD) method was used for numerical simulation,with results showing that the light extraction efficiency of LED with graphene grating structure was increased by about 1.7 times than LED with mixed-grating structure.