Study of Light Extraction Efficiency of Vertical Light Emiiting Diodes with Textured Surface roughening

• Main Authors: Guan-Jung Lai, 賴冠中
• Other Authors: Yuh-Renn Wu
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/49199079879382616898

碩士 === 國立臺灣大學 === 光電工程學研究所 === 100 === In this thesis, we have developed a 2D Monte Carlo ray tracing method combined with our developed 2D-DDCC ( 2 Dimentional Drift Diffusion Charge Control ) program to solve Drift-Diffusion and Poisson equations. By combining these two techniques, we can obtain the carrier information, radiative recombination rate to estimate the device light extraction efficiency. As we know, most materials used for LED production have much higher refractive indices than the air. This means that many photons will be reflected back into the semiconductor at the medium/air interface due to the small total reflection angle. They also may be absorbed and be turned into heat, and making the LED efficiency droop. Therefore, 2D Monte Carlo ray tracing method plays important roles in optimizing the light extraction efficiency in the LED device. So we have applied our method to study in this thesis. We have studied several factors to enhance light extraction efficiency such as the changes in different shaped of roughness, metal area with roughness surface or flat surface, different n-GaN thickness , multiple metal contacts and different metal sizes.