Versatile construction of van der Waals heterostructures using a dual-function polymeric film

Abstract

The proliferation of van der Waals (vdW) heterostructures formed by stacking layered materials can accelerate scientific and technological advances. Here, we report a strategy for constructing vdW heterostructures through the interface engineering of the exfoliation substrate using a sub-5 nm polymeric film. Our construction method has two main features that distinguish it from existing techniques. First is the consistency of its exfoliation process in increasing the yield and in producing large (>10,000 μm 2) monolayer graphene. Second is the applicability of its layer transfer process to different layered materials without requiring a specialized stamp-a feature useful for generalizing the assembly process. We demonstrate vdW graphene devices with peak carrier mobility of 200,000 and 800,000 cm 2 V −1 s −1 at room temperature and 9 K, respectively. The simplicity of our construction method and its versatility to different layered materials may open doors for automating the fabrication process of vdW heterostructures.

Reconfigurable electronics by disassembling and reassembling van der Waals heterostructures

“…1b . Here, the atomically flat PVA substrate could ensure the intimate contact and strong interaction between substrates and 2D materials 28 , 29 (compared to the weak vdW force within MoS 2 /WSe 2 heterostructure), which is essential to avoid the MoS 2 /substrate separation during following disassembling process. This is in great contrast to conventional transfer techniques using polydimethylsiloxane (PDMS) 30 or polypropylene carbonate (PPC) 31 as the handling polymers, where the whole vdWH stack would be either left on the substrate or picked up by the polymer, as schematically illustrated in Supplementary Fig.…”

Graphene Synthesis: Method, Exfoliation Mechanism and Large-Scale Production

“…The exfoliation method, using flake graphite or pyrolytic graphite with high crystallinity as raw material, separates the stacked sheets through external forces such as impact, [35], shear [36], friction [37], airflow expansion [38], blasting [39], chemical intercalation [40], redox [41], and electrode reactions [42], which significantly weaken and destroy the Van der Waals forces between graphite sheets to form single-layer, doublelayer, or few-layer graphene. According to the "power source" in the peeling process, it is categorized into electrochemical exfoliation [8,12,13,[25][26][27][28], oxide-assisted liquid phase exfoliation [6,9,43], mechanical exfoliation [27,[44][45][46][47], and three other categories.…”

Mitigation of Electromigration in Metal Interconnects via Hexagonal Boron Nitride as an Ångström‐Thin Passivation Layer

“…[ 31 ] We adopted a PVA‐assisted micro‐mechanical cleavage and exfoliation method to obtain monolayer hBN flakes from bulk hBN crystals. [ 32 ] All Cu interconnects studied had a length of 20 µm, a width of 5 µm, and a thickness of 55 nm. These dimensions were chosen to accommodate the average lateral size of monolayer hBN crystals obtainable through micro‐mechanical exfoliation (approximately 30 µm) and also adhere to contemporary manufacturing standards in IC dimensions.…”