Gui Yaliang, Miscuglio Mario, Ma Zhizhen, Tahersima Mohammad H, Sun Shuai, Amin Rubab, Dalir Hamed, Sorger Volker J
Department of Electrical and Computer Engineering, George Washington University, 800 22nd St. NW, Washington, DC, 20052, USA.
Omega Optics, Inc. 8500 Shoal Creek Blvd., Bldg. 4, Suite 200, Austin, Texas, 78757, USA.
Sci Rep. 2019 Aug 2;9(1):11279. doi: 10.1038/s41598-019-47631-5.
The class of transparent conductive oxides includes the material indium tin oxide (ITO) and has become a widely used material of modern every-day life such as in touch screens of smart phones and watches, but also used as an optically transparent low electrically-resistive contract in the photovoltaics industry. More recently ITO has shown epsilon-near-zero (ENZ) behavior in the telecommunication frequency band enabling both strong index modulation and other optically-exotic applications such as metatronics. However, the ability to precisely obtain targeted electrical and optical material properties in ITO is still challenging due to complex intrinsic effects in ITO and as such no integrated metatronic platform has been demonstrated to-date. Here we deliver an extensive and accurate description process parameter of RF-sputtering, showing a holistic control of the quality of ITO thin films in the visible and particularly near-infrared spectral region. We are able to custom-engineer the ENZ point across the telecommunication band by explicitly controlling the sputtering process conditions. Exploiting this control, we design a functional sub-wavelength-scale filter based on lumped circuit-elements, towards the realization of integrated metatronic devices and circuits.
透明导电氧化物类别包括氧化铟锡（ITO）材料，它已成为现代日常生活中广泛使用的材料，例如用于智能手机和手表的触摸屏，也用作光伏行业中的光学透明低电阻接触材料。最近，ITO在电信频段表现出近零介电常数（ENZ）行为，这使得强折射率调制以及诸如超材料等其他光学奇异应用成为可能。然而，由于ITO中存在复杂的固有效应，精确获得ITO中目标电学和光学材料特性的能力仍然具有挑战性，因此迄今为止尚未展示出集成超材料平台。在此，我们给出了射频溅射工艺参数的全面且准确的描述，展示了对可见光特别是近红外光谱区域中ITO薄膜质量的整体控制。通过明确控制溅射工艺条件，我们能够在整个电信频段定制设计ENZ点。利用这种控制，我们基于集总电路元件设计了一种功能性亚波长尺度滤波器，以实现集成超材料器件和电路。
