Clean assembly of van der Waals heterostructures with high-quality CVD-grown transition metal dichalcogenides

Transition metal dichalcogenides (TMDs) have become pivotal in exploring the strongly correlated physics of two-dimensional materials systems, such as superconductivity, Mott insulators, and moiré excitons, etc. Their unique optical and electronic properties offer a platform to investigate quantum phenomena at the nanoscale, particularly in van der Waals heterostructures. However, few-layer TMDs synthesized through chemical vapor deposition (CVD) present challenges in terms of crystal quality and the precision of transfer processes, limiting their utility in condensed matter experiments. In this work, we develop a refined method to assemble high-quality van der Waals heterostructures using CVD-grown monolayer TMDs (MoS₂, WSe₂, WS₂, MoSe₂). This method includes reliable hBN encapsulation and the formation of homo- and hetero-bilayer moiré superlattices, addressing the hurdles of maintaining structural integrity during transfer. The resulting heterostructures preserve the high crystalline quality of the CVD-grown TMD flakes, making them suitable for probing intricate quantum phenomena in low-dimensional electron systems.