Ultra-thin gold films: Towards 2D metals for photonic and optoelectronic applications

Abstract

Fabrication of continuous ultra-thin (<10 nm) and ultra-smooth gold films on different substrates is reported. Using a variety of electrical, optical and structural characterization techniques, we show that monolayer MoS2 can be superior to more conventional adhesion/seeding layers as an optical substrate for realizing ultra-thin gold films. Our results show that optical losses in ultrathin gold 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.