Only gold can pull this off: mechanical exfoliations of transition metal dichalcogenides beyond scotch tape

Abstract

Following in graphene’s wake, the scotch tape method became the key enabler for the preparation of 2D materials, providing easy access to high-quality materials mainly limited by low yield. At this time, transition metal dichalcogenides (TMDC) received tremendous attention as a promising class of two-dimensional (2D) semiconductors. The motivation to reach the 2D limit of TMDCs and many other layered materials has long been set, and with the rise of gold-mediated exfoliations towards the millimeter scale, the stacking of these 2D single-layer building blocks into artificial 3D lattices is more relevant than ever. On this note, this review presents the recent developments in gold-mediated exfoliations beyond scotch tape, accompanied by a methods walkthrough for such a process. These matured gold exfoliations unlock a whole palette of 2D building blocks, ready for the assembly of macroscopic van der Waals heterostructures, or twistronics. Ultimately, mechanical exfoliation as a key enabler for high-quality single layers, evolved from scotch tape to gold, and became an even more potent tool in the process.