Plasmonics in Atomically Thin Crystalline Silver Films
Plasmonics in Atomically Thin Crystalline Silver Films
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DOI：
10.1021/acsnano.9b01651
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发表时间：
2019-07-01
期刊：
影响因子：
17.1
通讯作者：
Garcia de Abajo, F. Javier
中科院分区：
文献类型：
--
作者：
Abd El-Fattah, Zakaria M.;Mkhitaryan, Vahagn;Garcia de Abajo, F. Javier
原子尺度上的光物质相互作用控制着光发射和激光等基本现象，同时实现了包括光电子学和光通信在内的基本日常技术。在这种情况下，等离子体激元，导电材料中的集体电子振荡，是重要的，因为它们允许在纳米尺度上操纵光场。石墨烯和其他二维晶体的出现将等离子体激元推到了真正的原子尺度，显示出吸引人的特性，如大的电可调性。然而，这些材料中的等离子体振子要么太宽，要么位于低频，远低于技术相关的近红外区。在这里，我们展示了锐利的近红外等离子体在光刻图案化的晶圆级原子级薄银晶体薄膜。我们测量的光谱揭示了窄的等离子体激元（质量因子类似于4），进一步支持的低薄层电阻相媲美的块体金属在几个原子层银膜下降到七个Ag（111）单层。良好的晶体质量和等离子体激元窄，尽管增加了一个薄的钝化电介质，这使得我们的样品对环境条件有弹性。在原子级薄的银中观察到的光谱尖锐和强约束的等离子体激元在电光调制和光学传感应用中具有巨大的潜力。
Light matter interaction at the atomic scale rules fundamental phenomena such as photoemission and lasing while enabling basic everyday technologies, including photovoltaics and optical communications. In this context, plasmons, the collective electron oscillations in conducting materials, are important because they allow the manipulation of optical fields at the nanoscale. The advent of graphene and other two-dimensional crystals has pushed plasmons down to genuinely atomic dimensions, displaying appealing properties such as a large electrical tunability. However, plasmons in these materials are either too broad or lying at low frequencies, well below the technologically relevant near-infrared regime. Here, we demonstrate sharp near-infrared plasmons in lithographically patterned wafer-scale atomically thin silver crystalline films. Our measured optical spectra reveal narrow plasmons (quality factor of similar to 4), further supported by a low sheet resistance comparable to bulk metal in few-atomic-layer silver films down to seven Ag(111) monolayers. Good crystal quality and plasmon narrowness are obtained despite the addition of a thin passivating dielectric, which renders our samples resilient to ambient conditions. The observation of spectrally sharp and strongly confined plasmons in atomically thin silver holds great potential for electro-optical modulation and optical sensing applications.