The synthesis of lateral heterostructures assembled by atomically-thin materials with distinct intrinsic properties is important for future heterojunction-embedded two-dimensional (2D) devices. Here we report an etching-assisted chemical vapor deposition method to synthesize large-area continuous lateral graphene/hexagonal boron nitride (Gr/h-BN) heterostructures on carbon-containing copper foils. The h-BN film is first synthesized on the copper foil, followed by hydrogen etching, and then epitaxial graphene domains are grown to form continuous lateral heterostructures. Analyses, including Raman spectroscopy, atomic force microscopy, scanning electron microscopy, x-ray photoelectron spectroscopy, and ultraviolet-visible absorption spectroscopy, are used to characterize the coexistence of both materials and the highly continuous nature of this lateral heterostructure. This facile and scalable synthesizing method enables the potential usage of Gr/h-BN heterostructure in both fundamental studies and related 2D devices.

Two-dimensional (2D) semiconductors like molybdenum disulfide (MoS2) exhibit superior performance at nanometer-scale thickness compared to silicon. Notably, multilayers are more resistant to breakage during transfer and boast enhanced electrical properties over monolayers. In this study, we synthesized 4-in. multilayer MoS2 using a rapid thermal processing system through the ammonium tetrathiomolybdate precursor thermolysis. A 200 nm-scale space confinement on the sample surface was used to reduce sulfur loss during annealing and to facilitate vacancy healing by self-feeding sulfur atoms. Various characterizations confirmed good crystallinity, surface flatness, and continuity, including Raman spectroscopy, x-ray photoelectron spectroscopy, scanning transmission electron microscopy, and atomic force microscopy. Moreover, these samples showed a significant enhancement in electron mobility. Our approach benefits efficiency, scalability, and procedural simplicity, paving a promising path toward large-scale production of multilayer 2D semiconductors.