Enhancement of light extraction efficiency of GaN-based light-emitting diode using ZnO sol-gel direct imprinting |
| |
Authors: | Seong-Hwan LeeKyeong-Jae Byeon Hyoungwon ParkJoong-Yeon Cho Ki-Yeon YangHeon Lee |
| |
Affiliation: | a Department of Materials Science and Engineering, Korea University, Seoul 136-701, Republic of Korea b Nano Fabrication Group, Samsung Advanced Institute of Technology (SAIT), Yongin 446-712, Republic of Korea |
| |
Abstract: | ZnO nano-structures were formed on transparent conducting oxide layer of GaN LED device on non-patterned (non-PSS) and patterned sapphire substrates (PSS). Since ZnO nano-structures were formed by sol-gel direct imprinting process, plasma etching process, which may create the plasma induced damage, was not used. Due to the ZnO nano-structures, light extracted from active layer was coupled with ZnO nano-structures and thus total internal reflection at the ITO layer was suppressed. According to electroluminescence measurement, the emission intensities of GaN LED devices with ZnO nano-structures, on both non-PSS and PSS sapphire substrates were increased by 20.5% and 19.0%, respectively, compared to GaN LED devices without ZnO nano-structures, due to the suppression of total internal reflection. Moreover, it is confirmed that there is no decrease of light extraction on side direction due to light focusing to vertical axis by nanostructure. Electrical performance of GaN LED devices were not degraded by ZnO sol-gel direct imprinting process. |
| |
Keywords: | Light extraction efficiency Light emitting diode Sol-gel direct imprinting ZnO PSS substrate EL measurement |
本文献已被 ScienceDirect 等数据库收录! |
|