利用金屬孔洞電極提升發光二極體之外部量子效率

Abstract

本論文提出自洽計算及傅立葉模型法探討金屬孔洞電極發光二極體之電性與光性。考慮光子循環效應下，以蒙地卡羅光跡追蹤法計算載子產生速率並加於電子電洞連續方程式中。入射光激發電極表面態使得大於臨界角仍有穿透率以及利用週期性結構造成布拉格散射，改變光子反射路徑來降低全反射效應。金屬孔洞電極不僅可以提升光萃取效率同時也可以解決電流擴散及散熱問題。此外我們也分析金屬孔洞長度、電極厚度的影響，在適當的電極設計下其外部量子效率與傳統平面式結構相比有顯著提升但仍低於表面粗化結構。

In this thesis, we present a self-consistent calculation and Fourier Modal Method to investigate the electrical and optical properties of light-emitting diodes with metallic hole array contacts. For the photon recycling effect, we include a generate rate in the electron-hole continuity equations which is obtained by the Monte-Carlo ray-tracing method. The limitation of the critical angle can be broken by surface-state assisted transmission. In addition, the light with large incident angles has the opportunity to be scattered into the light cone. Thus, the extraction efficiency can be improved. In addition, we studied the influences of the hole size as well as the contact thickness on the device performance. With a proper design we find that the external efficiency can be significantly improved which is larger than that for planar surface structures but lower than that for surface texture structures.