Wafer‐Scale Synthesis of V2O5 Single Crystals for Ultrahigh Doping of 2D Materials

Abstract The controllable growth of wafer‐scale single‐crystalline 2D materials is foundational for future electronic and photonic applications. Layer‐by‐layer integration enables the fabrication of 2D heterostructure with multiple functionalities, such as doping of 2D materials, which enhances the conductivity and tunes work function to improve electrical contacts. The synthesis of wafer‐scale single‐crystalline 2D dopants enables subsequent integration with other 2D materials, which can avoid lattice defects and interface scattering centers typically associated with heteroatom doping or amorphous dopant. However, the synthesis of single‐crystalline 2D dopants remains unexplored. Here, this study reports an effective approach to synthesize centimetre‐sized V 2 O 5 bulk single‐crystal and inch‐sized V 2 O 5 single‐crystalline films, which can efficiently dope graphene and transition metal dichalcogenides (TMDs). Interfacing graphene with single‐crystalline V 2 O 5 enables hole doping of graphene, achieving a carrier density of ≈10 13 cm −2 and carrier mobility of ≈4400 cm 2 V −1 s −1 . The preservation of carrier mobility of graphene is enabled by a defect‐free interface and large energies of surface optical phonon modes of V 2 O 5 . Combined with reliable wafer‐scale synthesis and layer‐by‐layer stacking techniques for fabricating 2D materials/V 2 O 5 heterostructure, the results provide a scalable method for uniform, stable and efficient doping, facilitating the integration of 2D heterostructure into high‐speed logic circuits and photonics for optical communications.