Enhanced near field mediated nanohole fabrication on silicon substrate by femtosecond laser pulse
Enhanced near field mediated nanohole fabrication on silicon substrate by femtosecond laser pulse
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DOI：
10.1016/j.apsusc.2007.01.025
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发表时间：
2007-05-30
影响因子：
6.7
通讯作者：
Obara, Minoru
中科院分区：
文献类型：
--
作者：
Nedyalkov, Nikolay N.;Miyanishi, Tomoya;Obara, Minoru
研究了在金颗粒附近近电磁场增强介导的硅表面纳米孔形成过程。使用直径为40、80和200纳米的金纳米球。在低于天然硅表面烧蚀阈值的影响下，激光脉冲照射样品，导致纳米级表面改性。研究了超短钛蓝宝石激光系统产生的基频（λ = 800 nm, 100 fs）和次谐波（λ = 400 nm, 250 fs）的纳米结构形成。利用时域有限差分（FDTD）仿真程序对近场分布进行了分析。在硅表面产生的形态变化的性质与激光照射的偏振和波长密切相关。当激光脉冲线极化时，产生的纳米孔形状在极化的e方向上被拉长。当激光辐射圆偏振时，孔的形状变得对称。烧蚀孔的大小取决于金颗粒的大小，因为最小的孔是由最小的颗粒产生的。激光能量和颗粒大小的变化使得制造横向尺寸从200 nm到40 nm以下的结构成为可能。在利用时域有限差分模型和米氏理论对近场特性进行仿真的基础上，对所得结果进行了解释。(C) 2007 Elsevier B.V.版权所有
Investigation of the process of nanohole formation on silicon surface mediated with near electromagnetic field enhancement in vicinity of gold particles is described. Gold nanospheres with diameters of 40, 80 and 200 nm are used. Irradiation of the samples with laser pulse at fluences below the ablation threshold for native Si surface, results in a nanosized surface modification. The nanostructure formation is investigated for the fundamental (lambda = 800 nm, 100 fs) and the second harmonic (lambda = 400 nm, 250 fs) of the laser radiation generated by ultrashort Ti:sapphire laser system. The near electric field distribution is analyzed by an Finite Difference Time Domain (FDTD) simulation code. The properties of the produced morphological changes on the Si surface are found to depend strongly on the polarization and the wavelength of the laser irradiation. When the laser pulse is linearly polarized the produced nanohole shape is elongated in the E-direction of the polarization. The shape of the hole becomes symmetrical when the laser radiation is circularly polarized. The size of the ablated holes depends on the size of the gold particles, as the smallest holes are produced with the smallest particles. The variation of the laser fluence and the particle size gives possibility of fabricating structures with lateral dimensions ranging from 200 nm to below 40 nm. Explanation of the obtained results is given on the basis simulations of the near field properties using FDTD model and Mie's theory. (C) 2007 Elsevier B.V. All rights reserved.