ITO表面粗化提高GaN基LED芯片出光效率  

Light-output Enhancement of GaN-based Light-emitting Diodes with Surface Textured ITO

作　　者：胡金勇[1] 黄华茂[1] 王洪[1] 胡晓龙[1] 

机构地区：[1]华南理工大学理学院物理系广东省光电工程技术研究开发中心,广东广州510640

出　　处：《发光学报》2014年第5期613-617,共5页Chinese Journal of Luminescence

基　　金：国家高技术研究发展计划(863)(2014AA032609);广东省战略性新兴产业发展专项资金(2010A081002009;2011A081301004;2012A080302003);中央高校基本科研业务费专项资金(2013ZM093;2013ZP0017)资助项目

摘　　要：使用现有生产线上工艺成熟且成本低廉的技术实现ITO粗化以提高GaN基LED蓝光芯片的出光效率是产业界重要的研究课题。本文通过普通光刻技术和湿法腐蚀技术,实现ITO表面粗化,有效地提高了LED芯片的输出光功率。输入电流为20 mA时,ITO层制备密集分布的三角周期圆孔阵列后,芯片输出光功率提升11.4%,但正向电压升高0.178 V;微结构优化设计后,芯片输出光功率提升8.2%,正向电压仅升高0.044 V。小电流注入时,密集分布的三角周期圆孔阵列有利于获得较高的输出光功率。大电流注入时,这种结构将导致电流拥挤,芯片的电光转化效率衰减严重。经过优化设计后的微结构阵列器件,具有较高的电注入效率,因此芯片的出光效率较高且随输入电流的增加而衰减的趋势较慢,因此更适合大电流下工作。The sophisticated techniques of photolithography and wet-etching are used to fabricate GaN-based LED chips with surface-textured ITO layer to enhance the light output efficiency. It is shown that the light-output power can be efficiently improved by this surface-textured method. After the triangle-lattice of close-packed micro-holes are fabricated, the light-output power of LED chips under the injection current of 20 mA exhibits 11.4% enhancement comparing to the conventional LED chips. However, the forward voltage correspondingly increases 0.178 V. With our proposed micro-structures, the light-output power can also be enhanced by 8.2%, while the forward voltage increases only 0.044 V. It is also shown that the close-packed micro-hole pattern benefits high light-output under small injection current. However, this pattern would induce current-crowding if the injection current become high, and thus the light-output efficiency would decrease significantly. On the other hand, our optimized micro-structure is help for high electric-injection efficiency. This induces a high light-output efficiency, and the efficiency droop can be suppressed. The proposed micro-structure is preferred for high power LED chips under large current injection.

关 键 词：LED ITO 表面粗化 出光效率 

分 类 号：TN304.2+3[电子电信—物理电子学]