Indium tin oxide (ITO)-based sandwich structures with the insertion of ultrathin (<10 nm) titanium nitride (TiN) are investigated as near-infrared (NIR) plasmonic materials. The structural, electrical, and optical properties reveal the improvement of the sandwich structures stemmed from TiN insertion. TiN is a well-established alternative to noble metals such as gold, elevating the electron conductivity of sandwich structures as its thickness increases. Dielectric permittivities of TiN and top ITO layers show TiN-thickness-dependent properties, which lead to moderate and tunable effective permittivities for the sandwiches. The surface plasmon polaritons (SPP) of the ITO–TiN–ITO sandwich at the telecommunication window (1480–1570 nm) are activated by prism coupling using Kretschmann configuration. Compared with pure ITO films or sandwiches with metal insertion, the reflectivity dip for sandwiches with TiN is relatively deeper and wider, indicating the enhanced coupling ability in plasmonic materials for telecommunications. The SPP spatial profile, penetration depth, and degree of confinement, as well as the quality factors, demonstrate the applicability of such sandwiches for NIR plasmonic materials in various devices.

中文翻译：

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用于近红外等离子材料的ITO–TiN–ITO三明治

研究了插入有超薄（<10 nm）氮化钛（TiN）的基于氧化铟锡（ITO）的三明治结构，作为近红外（NIR）等离子体材料。结构，电学和光学性能表明，由于TiN的插入，三明治结构得到了改善。TiN是金等贵金属的行之有效的替代品，随着厚度的增加，它可以提高三明治结构的电子电导率。TiN和顶层ITO层的介电常数显示出TiN厚度相关的特性，从而导致三明治的中介电常数和可调有效介电常数。ITO–TiN–ITO三明治夹层的表面等离激元极化子（SPP）在电信窗口（1480–1570 nm）处通过使用Kretschmann配置的棱镜耦合来激活。与纯ITO膜或带有金属插入物的三明治相比，含TiN的三明治的反射率下降相对更深和更宽，这表明用于电信的等离激元材料的耦合能力增强。SPP的空间轮廓，穿透深度和限制程度以及质量因素证明了此类三明治材料可用于各种设备中的NIR等离子体材料。