Photonic Crystal Design Of Overlay Of Light-Emitting Diode Based On Nitride

Light-emitting diode (LED) has a very wide range of applications in our life, due to its advantage, such as low-operating voltage and current, high reliability, durable, green and cheap. But for traditional LED, there exists many problems in the process of development, such as low-luminous efficiency, high cost. So it's very important to improve LED's light-extraction efficiency, especially in the time of energy saving.Yablonovitch and John put forward the concept of photonic crystals in1987, but it was not until1989, Yablonovitch and Gmitter first confirmed the three-dimensional photonic band structure by experience. And from then on, the research of photonic crystals began Thoroughly. Because it provided a new possible to improve the application of LED's luminous efficiencyBased on this background, this paper works on the design of photonic crystal forcing on the nitride LED's surface layer We provide the endorsement and guidance for improving LED's light-luminous efficiency. The paper mainly targets at the two-dimensional photonic crystal.First, we present and analysis LED and photonic crystal theory. Then we supply two kinds of simulation method of numerical calculation: Plane Wave Expansion Method(PWE) and Finite Difference Time-Domain method(FDTD). Based on the forward method, we analyze and compute the two-dimensional photonic crystal.Secondly, we analyze several typical two-dimensional photonic crystal structures(square-rods, square-holes, triangle-rods, triangle-holes, honey-rods, honey-holes) by using MPB and MEEP,which we can get the best structure parameters.Finally, with the data and parameters derived above, we use FDTD to simulate the LED luminous principle and cover the layer of P-GaN with photonic crystal. In order to optimize the effect of its transmission spectrum, we add a semicircle ball structure to the dielectric rods. By analyzing the transmission of energy, we verified the influence of photonic crystal on LED. The results has a great guidance on light emitting of LED.