Patterned Assembly of Transition Metal Dichalcogenide/Graphene Heterostructures via Direct Laser Writing

Abstract

Connecting two-dimensional (2D) material layers via interface linkers represents a new avenue for fabricating 2D heterostructures. Utilizing light to remotely modulate this interface function allows for seamless assembly and patterning in a single run. Here, an efficient method for fabricating patterned 2D heterostructures using direct laser writing is demonstrated, drawing a conceptual parallel to laser printing. In the approach, functionalized transition metal dichalcogenide (TMD) dispersions serve as inks, graphene as the substrate, and a Raman laser as the patterning tool. Unlike laser printing's electrostatic interactions, the method achieves patterned assembly through covalent bonding between TMDs and graphene. Selective Raman laser irradiation of functionalized TMD/graphene heterostructures triggers localized reactions, forming chemically modified domains exclusively in the laser-irradiated regions, as confirmed by Raman spectroscopy, Kelvin probe force microscopy (KPFM), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Experimental and theoretical analyses of the interface composition and structure provide new insights into laser-induced chemistry. The work demonstrates the potential for high-throughput assembly of customizable 2D heterostructures, with enhanced compatibility for subsequent patterning through photolabile linkers and photoinduced coupling. Additionally, the results provide deeper insights into chemistry within confined 2D spaces, offering a novel approach to nanoscale heterostructure engineering.