Ultrathin and ultrasmooth gold films on monolayer MoS2

TL;DR

This paper demonstrates that monolayer MoS2 can serve as an effective adhesion layer for depositing continuous, ultrathin gold films of 3-4 nm thickness, enabling flexible, transparent nanophotonic devices with metallic properties.

Contribution

It introduces the use of monolayer MoS2 as a novel adhesion layer for ultrathin gold films, facilitating the creation of continuous, ultrasmooth metallic layers at nanometer scale.

Findings

Ultrathin gold films on MoS2 exhibit metallic properties down to 3-4 nm.

Optical losses increase as film thickness decreases, due to fine-grained structure and voids.

Atomic-scale MoS2 interfaces can be transferred to various substrates for advanced device applications.

Abstract

Sub-10 nm continuous metal films are promising candidates for flexible and transparent nanophotonics and optoelectronics applications. In this Letter, we demonstrate that monolayer MoS2 is a perspective adhesion layer for the deposition of continuous conductive gold films with a thickness of only 3-4 nm. Optical properties of continuous ultrathin gold films deposited on two-dimensional MoS2 grown by chemical vapor deposition are investigated by spectroscopic ellipsometry over a wide wavelength range (300-3300 nm). Results show that optical losses in ultrathin films increase with decreasing thickness due to the fine-grained structure and the presence of a small number of voids, however, they exhibit metallic properties down to a thickness of 3-4 nm. The atomic-scale MoS2 interfaces can be transferred to any substrate and thus open up new opportunities for the creation of metasurfaces and a new type of van der Waals heterostructures with atomically thin metal layers.