Universal transfer of 2D materials grown on Au substrate using sulfur intercalation

Abstract

Herein, we report on a novel method for transferring two-dimensional (2D) materials grown on Au substrates using sulfur intercalation between the 2D materials and the Au surfaces. The strong nature of the S–Au bond allows intercalation of sulfur atoms into their interface, under a sulfurrich atmosphere, at 600 ∘C. The relaxed interfacial interaction achieved via intercalation is carefully confirmed by recovering phonon mode and work function of tungsten disulfide (WS2) in Raman spectra and Kelvin probe force microscopy, and, more importantly, by observing the expansion of the interfacial distance, from 0.24 to 0.44 nm, using cross-sectional transmission electron microscopy. The released interactions facilitate delamination of WS2 from the Au surface, using an electrochemical bubbling method. The resultant Au foil then is reused for repeated WS2 growth. The successful transfer of other 2D materials, including molybdenum disulfide and hexagonal boron nitride, is also demonstrated. Our strategy advances the use of Au substrates for growing wafer-scale 2D monolayers.