Jeong Hyun, Kim Yong Hwan, Seo Tae Hoon, Lee Hong Seok, Kim Jun Sung, Suh Eun-Kyung, Jeong Mun Seok
Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju, South Korea.
Opt Express. 2012 May 7;20(10):10597-604. doi: 10.1364/OE.20.010597.
We report on the efficiency enhancement in GaN-based light-emitting diodes (LEDs) using ZnO micro-walls grown by a hydrothermal method. The formation of ZnO micro-walls at the indium tin oxide (ITO) border on the LED structure is explained by the heterogeneous nucleation effect. The light output power of LEDs with ZnO micro-walls operated at 20 mA was found to increase by approximately 30% compared to conventional LEDs. Moreover, the finding of nearly the same current-voltage characteristics of GaN-based LEDs with and without a ZnO micro-wall shows that the ZnO micro-wall does not influence the electrical properties of the device but only leads to an increase in the light extraction efficiency. From the confocal scanning electroluminescence results, we confirm that ZnO micro-walls enhance the light output power via the photon wave-guiding effect.
我们报道了利用水热法生长的ZnO微壁提高基于GaN的发光二极管（LED）的效率。LED结构上氧化铟锡（ITO）边界处ZnO微壁的形成是由异质成核效应解释的。发现具有ZnO微壁的LED在20 mA电流下工作时，其光输出功率与传统LED相比增加了约30%。此外，有和没有ZnO微壁的基于GaN的LED具有几乎相同的电流-电压特性这一发现表明，ZnO微壁不会影响器件的电学性能，而只会导致光提取效率的提高。从共聚焦扫描电致发光结果来看，我们证实ZnO微壁通过光子波导效应提高了光输出功率。
