Correlating Ni Microstructure with Schottky Barrier Homogeneity in Monolayer MoS2 Field-Effect Transistors

The performance of electronic devices based on two-dimensional (2D) transition metal dichalcogenides is critically limited by the contact resistance at the metal-semiconductor interface.While the Schottky barrier height (SBH) is a key parameter, its spatial inhomogeneity, often governed by the metal's microstructure, remains a significant yet underexplored challenge.This work presents a systematic investigation directly correlating the microstructure of nickel (Ni) contacts with the electrical homogeneity and performance of monolayer MoS2 field-effect transistors (FETs).By engineering Ni contacts with distinct microstructures-varying in grain size and crystallographic orientation through controlled deposition and annealing-we demonstrate that contacts with larger, (111)-textured grains achieve a superior interface.Through nanoscale structural characterization and detailed electrical analysis, we show that this optimized microstructure reduces the standard deviation of the SBH distribution by over 50% compared to fine-grained, polycrystalline contacts.This enhanced homogeneity translates directly to a 40% reduction in median specific contact resistivity (to 2.8km) and a twofold increase in the ON-state current.Our findings establish nanoscale control of metal microstructure as a fundamental strategy for achieving high-performance and reliable 2D electronic devices.

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