Highly Tunable Schottky Barrier to 2D Semiconductors Enabled by an Inorganic-Molecular-Crystal Tunneling Layer

Effective tuning of the Schottky barrier, which determines charge transport across the metal-semiconductor interface, is essential for optimizing the performance of electronics and optoelectronic devices. However, interfacial disorders and orbital overlap between metals and semiconductors induce Fermi-level pinning (FLP), making the Schottky barrier height (SBH) largely insensitive to metal work function. Here, we demonstrate that depositing an ultrathin inorganic molecular crystal layer of Sb₂O₃ between metal and 2D semiconductors can eliminate FLP, enabling highly tunable SBH modulation. Owing to its van der Waals structure, Sb₂O₃ introduces no excess defects and protects the fragile 2D channel from metal deposition damage, yielding a clean, defect-free interface. Incorporation of Sb₂O₃ tunneling layer significantly reduces the SBH in 2D MoS₂ transistors, and the polarity of 2D WSe₂-based FET can be switched from n-type to p-type via adjusting the contact metal work function. The pinning factor turns from -0.11 to around -0.93, approaching the ideal Mott-Schottky limit. This scalable strategy offers broad applicability in high-performance 2D electronics.