MIM-Diode-Like Rectification in Lateral 1T/1H/1T-MoS$_2$ Homojunctions via Interfacial Dipole Engineering

Lateral two-dimensional (2D) tunnel diodes that reproduce metal-insulator-metal (MIM)-diode-like rectification without using dissimilar contacts are attractive for scalable nanoelectronics. MoS$_2$ can exist in both the semiconducting 1H phase and the metallic 1T phase, enabling phase-engineered homojunctions within a single material. First-principles electronic structure and quantum transport calculations show that phase-engineered 1T/1H/1T--MoS$_2$ homojunctions exhibit pronounced MIM-diode-like rectification originating from interfacial charge transfer at asymmetric 1T/1H interfaces. The charge transfer establishes interface dipole steps that impose a built-in potential drop across the 1H barrier, thereby generating a trapezoidal tunnel barrier at zero bias. In contrast, symmetric 1T/1H interfaces do not form interface dipoles and show no rectification. To clarify the microscopic origin, a lateral graphene/hexagonal-boron-nitride/graphene junction is analyzed as a minimal MIM diode analogue with a simple interface and well-defined barrier, confirming that interface-induced dipoles, rather than work-function difference, enable the effect. The mechanism operates entirely within a single monolayer material system and does not rely on out-of-plane stacking, highlighting compatibility with phase patterning in 2D semiconductors. These results establish lateral 1T/1H/1T--MoS$_2$ as a fully 2D, single-material platform for MIM-diode-like rectification and position interface-dipole engineering as a general strategy for ultrathin in-plane diodes, high-frequency detectors, and energy-harvesting tunnel devices.