Integrating Surface Textures on ZnO Substrate for High Light Extraction Efficiency Light-Emitting Diode
Integrating Surface Textures on ZnO Substrate for High Light Extraction Efficiency Light-Emitting Diode
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DOI：
10.1021/jp501574a
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发表时间：
2014-06
影响因子：
3.7
通讯作者：
Qinghong Zheng;Dan Zhang;Jin Huang;Yonghao Wang;F. Huang
中科院分区：
文献类型：
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作者：
Qinghong Zheng;Dan Zhang;Jin Huang;Yonghao Wang;F. Huang
由于ZnO材料的折射率较大，ZnO基发光二极管（LED）的光提取效率（LEE）受到全反射的限制。我们提出了一种结合实验和计算的方法来研究集成的表面纹理的光提取效率从ZnO材料的影响。分别在HCl和KOH溶液中对O极性ZnO单晶进行选择性和各向异性刻蚀，得到了六棱锥和凹坑织构。通过两步湿法刻蚀工艺将密集的六棱锥集成到六边形凹坑中。光线追迹模拟结果表明，衬底织构化可以通过提高LEE和改善光场均匀性来改善ZnO基LED的性能。通过将金字塔纹理集成到六边形凹坑中，相对于平面ZnO单晶的集成光致发光提取提高了117%。
Due to the large refractive index of ZnO material, light extraction efficiency (LEE) of ZnO based light-emitting diode (LED) is limited by the total reflection. We present a combined experimental and computational approach to study the effects of integrated surface textures on the efficiency of light extraction from the ZnO material. Hexagonal pyramids and pits textures were obtained by selective and anisotropic etching of O-polarity ZnO single crystal in HCl and KOH solutions, respectively. Dense hexagonal pyramids were integrated into the hexagonal pits via a two-step wet etching process. Ray-tracing simulations indicate that the substrate texturing can improve the performance of the ZnO based LEDs by enhancing the LEE and improving the light field uniformity. The integrated photoluminescence extraction was improved by a factor of 117% with respect to that of a planar ZnO single crystal through integrating the pyramids textures into the hexagonal pits.