高效率光子晶体發光二極体之研究

Abstract

如 何加強 LEDs 的發光效率呢? 加強內部量子效率是一個根本的方式 ,但是這須要從磊晶成長計技術著手,要付出相當大的成本. 或可以改善級汲光效率為途徑, 例如表面粗糙化,較厚的窗戶層 , 或者以金屬為反射面. 在本研討工作 ,採取光子晶體反射層為提高發光效率的手段. 光子晶體反射層採用介電質材料. 介電質材料是以電偶極振盪為其光反射機制. 因此僅有及微小的能量耗損.是極佳的反光材料 . 本研討將比較光子晶體LED與 ITO LED , 金屬反射鏡LED 之效能差異. 藉此來說明光子晶體LED的優越性.

How to maximize the efficiency of LEDs? One way is to increase the internal quantum efficiency, this way should put efforts in epitaxy ; the other way is to increase the extraction efficiency .There are many techniques to improve the extraction efficiency, such as rough surface, thick window-layer, wafer bonding with metal reflector…etc. , In this study , we try a new method to increase the light output , that is ,photonic crystal technique . The reflectance ratio of 1dimension photonic crystal reflector is better than metal reflector . It is because the material of PhC layers used for LEDs is dielectrics . The light reflection of dielectrics is dipole-oscillation mechanism , this way, the incident light will not lose energy. Here we will compare the PhC LED to the ITO LED and Metal reflector LED to convince the advantage of the photonic crystal technology .