Khan Firoz, Baek Seong-Ho, Kaur Jasmeet, Fareed Imran, Mobin Abdul, Kim Jae Hyun
Division of Nano and Energy Convergence Research, Daegu Gyeongbuk Institute of Science & Technology (DGIST), 50-1 Sang-Ri, Hyeonpung-Myeon, Dalseong-gun, Daegu, 711-873, Republic of Korea.
Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi, 110 012, India.
Nanoscale Res Lett. 2015 Dec;10(1):376. doi: 10.1186/s11671-015-1087-9. Epub 2015 Sep 29.
In this paper, we present an optical model that simulates the light trapping and scattering effects of a paraboloid texture surface first time. This model was experimentally verified by measuring the reflectance values of the periodically textured silicon (Si) surface with the shape of a paraboloid under different conditions. A paraboloid texture surface was obtained by electrochemical etching Si in the solution of hydrofluoric acid, dimethylsulfoxide (DMSO), and deionized (DI) water. The paraboloid texture surface has the advantage of giving a lower reflectance value than the hemispherical, random pyramidal, and regular pyramidal texture surfaces. In the case of parabola, the light can be concentrated in the direction of the Si surface compared to the hemispherical, random pyramidal, and regular pyramidal textured surfaces. Furthermore, in a paraboloid textured surface, there can be a maximum value of 4 or even more by anisotropic etching duration compared to the hemispherical or pyramidal textured surfaces which have a maximum h/D (depth and diameter of the texture) value of 0.5. The reflectance values were found to be strongly dependent on the h/D ratio of the texture surface. The measured reflectance values were well matched with the simulated ones. The minimum reflectance value of ~4 % was obtained at a wavelength of 600 nm for an h/D ratio of 3.75. The simulation results showed that the reflectance value for the h/D ratio can be reduced to ~0.5 % by reducing the separations among the textures. This periodic paraboloidal structure can be applied to the surface texturing technique by substituting with a conventional pyramid textured surface or moth-eye antireflection coating.
在本文中，我们首次提出了一种光学模型，该模型可模拟抛物面纹理表面的光捕获和散射效应。通过测量不同条件下呈抛物面形状的周期性纹理硅（Si）表面的反射率值，对该模型进行了实验验证。通过在氢氟酸、二甲基亚砜（DMSO）和去离子（DI）水的溶液中对硅进行电化学蚀刻，获得了抛物面纹理表面。与半球形、随机金字塔形和规则金字塔形纹理表面相比，抛物面纹理表面具有更低反射率值的优势。对于抛物面而言，与半球形、随机金字塔形和规则金字塔形纹理表面相比，光可以在硅表面的方向上被集中。此外，在抛物面纹理表面中，通过各向异性蚀刻持续时间，与半球形或金字塔形纹理表面（其最大h/D（纹理的深度和直径）值为0.5）相比，可以有4甚至更大的最大值。发现反射率值强烈依赖于纹理表面的h/D比。测量的反射率值与模拟值匹配良好。对于h/D比为3.75的情况，在波长600nm处获得了约4%的最小反射率值。模拟结果表明，通过减小纹理之间的间距，h/D比的反射率值可以降低到约0.5%。这种周期性抛物面结构可以通过替代传统的金字塔纹理表面或蛾眼抗反射涂层应用于表面纹理化技术。
