Tunable plasmons in ultrathin metal films
Tunable plasmons in ultrathin metal films
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DOI：
10.1038/s41566-019-0366-x
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发表时间：
2019-05-01
期刊：
影响因子：
35
通讯作者：
Pruneri, Valerio
中科院分区：
文献类型：
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作者：
Maniyara, Rinu Abraham;Rodrigo, Daniel;Pruneri, Valerio
当一个或多个维度降低到纳米尺度时，电子，光子及其等离子体相互作用的物理学发生了巨大变化（1）。例如，石墨烯显示出独特的电学、光学和等离子体性质，这些性质可以通过门控或化学掺杂来调节（2-5）。类似地，低至原子厚度的双金属薄膜（UTMF）可以具有新的量子光学效应（6，7）、特殊的介电性质（8）和预测的强等离子体激元（9，10）。然而，真正的二维等离子体在金属迄今为止一直难以捉摸，因为在生产足够薄的连续膜的大面积的困难。由于沉积技术，即使在1 nm的厚度，允许渗滤，我们展示了几个纳米厚的金UTMF的等离子体激元，新的分散制度和大的电调谐性的明确证据。波长为1.5-5 μ m的共振峰通过使用相对低的电压进行选通而被移动数百纳米并且被幅度调制百分之几十。研究结果为金属在等离子体应用中的应用提供了方法，如电光调制、生物传感和智能窗。
The physics of electrons, photons and their plasmonic interactions changes greatly when one or more dimensions are reduced down to the nanometre scale(1). For example, graphene shows unique electrical, optical and plasmonic properties, which are tunable through gating or chemical doping(2-5). Similarly, ultrathin metal films (UTMFs) down to atomic thickness can possess new quantum optical effects(6,7), peculiar dielectric properties(8) and predicted strong plasmons(9,10). However, truly two-dimensional plasmonics in metals has so far been elusive because of the difficulty in producing large areas of sufficiently thin continuous films. Thanks to a deposition technique that allows percolation even at 1 nm thickness, we demonstrate plasmons in few-nanometre-thick gold UTMFs, with clear evidence of new dispersion regimes and large electrical tunability. Resonance peaks at wavelengths of 1.5-5 mu m are shifted by hundreds of nanometres and amplitude-modulated by tens of per cent through gating using relatively low voltages. The results suggest ways to use metals in plasmonic applications, such as electro-optic modulation, biosensing and smart windows.