Velický Matěj, Hendren William R, Donnelly Gavin E, Katzen Joel M, Bowman Robert M, Huang Fumin
Nanotechnology. 2018 Jul 6;29(27):275205. doi: 10.1088/1361-6528/aabec1. Epub 2018 Apr 17.
Metals have been increasingly used as substrates in devices based on two-dimensional (2D) materials. However, the high reflectivity of bulk metals results in low optical contrast (<3%) and therefore poor visibility of transparent mono- and few-layer 2D materials on these surfaces. Here we demonstrate that by engineering the complex reflectivity of a purpose-designed multilayer heterostructure composed of thin Au films (2-8 nm) on SiO/Si substrate, the optical contrast of graphene and graphene oxide (GO) can be significantly enhanced in comparison to bulk Au, up to about 3 and 5 times, respectively. In particular, we achieved ∼17% optical contrast for monolayer GO, which is even 2 times higher than that on bare SiO/Si substrate. The experimental results are in good agreement with theoretical simulations. This concept is demonstrated for Au, but the methodology is applicable to other metals and can be adopted to design a variety of high-contrast metallic substrates. This will facilitate research and applications of 2D materials in areas such as plasmonics, photonics, catalysis and sensors.
金属越来越多地被用作基于二维（2D）材料的器件的衬底。然而，块状金属的高反射率导致光学对比度低（<3%），因此透明的单层和少数层二维材料在这些表面上的可见性较差。在这里，我们证明，通过设计由SiO/Si衬底上的薄金膜（2-8纳米）组成的特定多层异质结构的复反射率，与块状金相比，石墨烯和氧化石墨烯（GO）的光学对比度可以显著提高，分别高达约3倍和5倍。特别是，我们实现了单层GO约17%的光学对比度，这甚至比在裸露的SiO/Si衬底上的对比度高出2倍。实验结果与理论模拟结果吻合良好。这个概念是针对金进行演示的，但该方法适用于其他金属，并且可以用于设计各种高对比度金属衬底。这将促进二维材料在等离子体学、光子学、催化和传感器等领域中的研究和应用
