藉由不同結構電流阻擋層來提高GaN發光二極體之出光效率研究

本研究主要藉由在電流阻擋層的結構上做設計，由一般的單層結構的SiO_2到提升反射率之布拉格反射鏡多層結構，藉以改變電流方向，並透過此不同電流阻擋層來提取電極下方所遮蔽的光，以研究其發光強度、發光角度及電壓的變化。研究中藉由不同結構來改善電流擴散的特性以及減少電極下方光的吸收，來研製提升發光二極體發光效率之製程。後續再以高倍光學顯微鏡分析其結構特性與外觀差異，積分球量測發光強度，四點探針量測其導電特性。研究結果顯示在不同結構中，以3層布拉格反射鏡結構的電流阻擋層具有最佳的光電特性。在光學量測中不同厚度的單層SiO_2結構其亮度約增加3.5~4%，電壓增加較大約0.2V，而多層結構中5層布拉格反射鏡結構的電流阻擋層於亮度約提升了4.5%，但電壓增加較多，約增加0.3V，其中最佳的為具有3層布拉格反射鏡結構的電流阻擋層於亮度方面約提高了6.5%，而其電壓僅增加了0.05V，幾乎是不需額外電壓的增加。

關鍵字

電流阻擋層

並列摘要

In this study, the changed structures of the current blocking layer had been done. The current direction had been modified by the single layer structure and the multi-layer Distributed Bragg Reflector structures, which had led the LED to have more higher reflectivity. Light was extracted from the shielding electrode by this below type of current blocking layer. The luminous intensity, light angle and voltage variations had also been measured. The different structures improve current spreading and reduce the light absorption below the electrodes , The emitting efficiency of LED had been enhanced by this process. The optical microscopy had been used to analysis structural characteristics. The luminous intensity had been measured by integrating sphere and the electrical property had been measured by four-point probe. The results shown 3-layer Distributed Bragg Reflector structure of the current blocking layer has the best optical properties, the different thickness of single layer structure increases the brightness about 3.5 to 4%, a large increase in the voltage about 0.2V, the multilayer structure current barrier layer of the 5-layer Distributed Bragg Reflector structure improved in brightness about 4.5%, but the voltage increased, more than 0.3V . The best current barrier layer is 3-layer Distributed Bragg reflector structure, which the brightness improved about 6.5%, and the voltage increase only 0.05V.