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.