Fig. 1: Fabrication of two-dimensional gold flakes (2DGFs).
From: Large area single crystal gold of single nanometer thickness for nanophotonics
a Schematic illustration of the atomic-level precision etching approach for fabricating 2DGFs. The light blue arrow shows the reaction of cysteamines with oxygen molecules to form cysteamine radicals (CYS cysteamine, CYS• cysteamine radical). Inset, enlarged view of the etching of gold atoms with cysteamine radicals to form a soluble gold-thiolate complex. b Optical transmission micrographs of a gold flake taken at various etching times. c Measured thickness of the gold flake as a function of the etching time. The dashed line is a linear fit to the measured data points. d Optical reflection micrographs of a 2DGF folded on itself. e Scanning electron microscopy image of a 3.8-nm-thick 2DGF suspended across a groove. f Atomic force microscopy (AFM) image of a gold flake locally etched to implement a concentric ring pattern. A line scan along the indicated dashed line is also shown.
