Titanium oxide nanotube arrays for high light extraction efficiency of GaN-based vertical light-emitting diodes.
Titanium oxide nanotube arrays for high light extraction efficiency of GaN-based vertical light-emitting diodes.
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DOI：
10.1039/c6nr00503a
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发表时间：
2016-05
期刊：
影响因子：
6.7
通讯作者：
Young-Chul Leem;O. Seo;Yong-Ryun Jo;Joon-Heon Kim;Jaeyi Chun;Bong-Joong Kim;D. Noh;W. Lim;Yong-Il Kim;Seong-Ju Park
中科院分区：
文献类型：
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作者：
Young-Chul Leem;O. Seo;Yong-Ryun Jo;Joon-Heon Kim;Jaeyi Chun;Bong-Joong Kim;D. Noh;W. Lim;Yong-Il Kim;Seong-Ju Park
以ZnO纳米棒（NRs）为模板，通过液相转化工艺在n-GaN表面制备了高效InGaN/GaN多量子阱（MQW）垂直发光二极管（vled）。在注入电流为350 mA时，与ZnO纳米管和平面vled相比，TiO2纳米管的vled的光输出功率分别提高了23%和189%。光输出的大幅增强归因于VLED的n-GaN层向TiO2 NTs的有效光注入的协同效应，因为TiO2 NTs末端具有良好的折射率匹配和优越的光提取到空气中。利用时域有限差分模拟研究了不同结构的TiO2纳米管在vled上的光传输，结果表明，TiO2纳米管的壁厚应保持在20 nm左右，才能从vled中获得较好的光提取效果。
TiO2 nanotube (NT) arrays were fabricated on the surface of n-GaN through a liquid-phase conversion process using ZnO nanorods (NRs) as a template for high-efficiency InGaN/GaN multiple quantum well (MQW) vertical light-emitting diodes (VLEDs). The optical output power of the VLEDs with TiO2 NTs was remarkably enhanced by 23% and 189% at an injection current of 350 mA compared to those of VLEDs with ZnO NRs and planar VLEDs, respectively. The large enhancement in optical output is attributed to a synergistic effect of efficient light injection from the n-GaN layer of the VLED to TiO2 NTs because of the well-matched refractive indices and superior light extraction into air at the end of the TiO2 NTs. Light propagation along various configurations of TiO2 NTs on the VLEDs was investigated using finite-difference time domain simulations and the results indicated that the wall thickness of the TiO2 NTs should be maintained close to 20 nm for superior light extraction from the VLEDs.