Scalable Etchant-Free Transfer Technique for Low-Dimensional Materials from Metal Thin Film Surfaces

Graphene nanoribbons (GNRs) are quantum materials with tunable bandgap and electronic properties that depend strongly on ribbon width and edge structures, making them promising candidates for future electronics, particularly as channel materials in field-effect transistors (FETs). A bottom-up approach allows for atomic-level control of GNR structure and edge configuration through a catalytic reaction on metal surfaces, typically gold. To integrate GNRs into devices, they must be transferred from gold to insulating substrates. Current methods, involving gold film etching or polymer-assisted electrochemical transfer from bulk gold, face challenges such as potential damage, contamination by etchants, and limited scalability. We propose a new technique to transfer GNRs from large area gold thin films without etchants by using low melting point alloys. This method involves depositing GNRs on a gold film, supporting them with a polymer layer, and placing them onto molten alloy for electrochemical transfer. The alloy serves as an anode during the process to detach the polymer and GNRs from the gold film for transfer onto desired substrates, followed by polymer removal. This research advances GNR transfer techniques and offers scalable solutions for various low-dimensional materials. The method is applicable not only to carbon-based materials but also to transition metal dichalcogenides (TMDs), MXenes, hexagonal boron nitride (hBN), and other 2D materials obtained from metal solid solutions.