高反射率电极及n-GaN表面粗化的InGaN/GaN多量子阱LED的研制

InGaN/GaN Multiple Quantum Wells LEDs with High Reflective Electrode Pads and Roughened n-GaN Surface

摘要:

采用高反射率的Cr/Al/Pd/Au作为LED的p-GaN和n-GaN金属电极,替代低反射率的Cr/Pd/Au电极,减小了金属电极对光的吸收,使入射到高反射率金属电极的光经过反射后增加了出射概率,提高了光萃取效率.通过进一步粗化n-GaN表面,抑制了n-GaN/空气界面的光全反射,提高了光萃取效率.实验结果表明,在350mA电流下,采用高反射率的Cr/Al/Pd/Au电极的LED相比传统电极LED光输出增加了14.3%;结合n-GaN表面粗化,LED的光输出则增加了35.3%.

Abstract:

In this paper,high reflective Cr/Al/Pd/Au metals were adopted as p and n-type electrode pads instead of the low reflective Cr/Pd/Au.Most of the photons emitting to Cr/Al/Pd/Au metals were reflected,which increases the probability of light emitting out of LED and improves the light extraction efficiency (LEE).Combining with the roughened n-GaN surface,the total internal reflection at the interface between n-GaN and air was inhibited and the LEE was further improved.In comparison to LED with Cr/Pd/Au electrode pads,the light output of LED with Cr/Al/Pd/Au electrode pads was enhanced by 14.3% at an injection current of 350mA,furthermore,the light output of LED with Cr/Al/Pd/Au electrode pads and roughened n-GaN layer is improved by 35.3%.