THz time-domain spectroscopy of nanometric-thick gold layers
THz time-domain spectroscopy of nanometric-thick gold layers
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纳米金层的太赫兹时域光谱
DOI：
10.1109/icimw.2004.1422166
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
J. Coutaz
中科院分区：
文献类型：
--
作者：
F. Garet;L. Duvillaret;J. Coutaz
利用THzTDS技术研究了厚度从1.5 nm到30 nm的蒸发金膜的远红外(0.1-1.8THz)响应。在该频域中，自由载流子主要决定金属材料的光学性质。这些超薄膜是由当厚度大于一个临界值，即渗流阈值时接触的岛屿组成的，导致对这些厚度的金属响应。远低于这个阈值，岛是完全分开的，不允许导电：薄膜表现为电介质层。在临界厚度附近，观察到渗流型电导率。THzTDS可以清楚地观察到这三个区域，并确定远红外超薄金层的复折射率。
Using THz time-domain spectroscopy (THz TDS), we study the far infrared (0.1-1.8 THz) response of evaporated gold films whose thicknesses spread from 1.5 up to 30 nm. In this frequency domain, free carriers mainly dictate the optical properties of metallic materials. These ultra thin films are composed of islands that are in contact when the thickness is larger than a critical value, namely the percolation threshold, leading to a metallic response for those thicknesses. Well below this threshold, the islands are completely separated and no electric conduction is allowed: the films behave as dielectric layers. Around the critical thickness, percolation-type conductivity is observed. THz TDS permits to clearly observe these 3 regimes and to determine the complex refractive index of ultra thin gold layers in the far infrared.