Unveiling the Contact Physics of Molecular Crystal Sb2O3: From Conventional Metals to 2D Electride Electrodes for High-Performance Transistors

Two-dimensional inorganic molecular crystals (IMCs) are emerging van der Waals materials with discrete molecular cages and wide bandgaps, but their contact physics with metal electrodes remains largely unexplored. Here, we report a first-principles study of monolayer Sb2O3, a prototypical IMC, contacted with bulk metals (Ag, Au, Cu, Ni, Pd, Pt) and 2D electrodes (graphene and electride Ba2N). Sb2O3 is dynamically and thermally stable, with an indirect bandgap of 3.26 eV and a work function of 5.68 eV. Cu forms a true n-type Ohmic contact; Ag and Ni form thin n-type Schottky barriers with moderate tunnel resistance; Au, Pd, and Pt form thick n-type Schottky barriers with high resistance due to large work functions and stronger Fermi-level pinning. The extracted pinning factor S = 0.62 indicates moderate suppression of metal-induced gap states. Remarkably, Ba2N creates an atomically sharp van der Waals interface, delivering an n-type Ohmic contact with near-zero Schottky barrier, ∼100% tunneling probability, and tunneling specific resistivity approaching the quantum limit, far outperforming graphene. These results establish Sb2O3 as a viable channel material and Ba2N as a transformative electrode for low-resistance molecular-crystal nanoelectronics.