Tuning Schottky Barrier of Single-Layer MoS₂ Field-Effect Transistors with Graphene Electrodes

Two-dimensional materials have the potential to be applied in flexible and transparent electronics. In this study, single-layer MoS₂ field-effect transistors (FETs) with Au/Ti-graphene heteroelectrodes were fabricated to examine the effect of the electrodes on the electrical properties of the MoS₂ FETs. The contact barrier potential was tuned using an electric field. Asymmetrical gate behavior was observed owing to the difference between the MoS₂ FETs, specifically between the MoS₂ FETs with Au/Ti electrodes and those with graphene electrodes. The contact barrier of the MoS₂ FETs with Au/Ti electrodes did not change with the electric field. However, the contact barrier at the MoS₂-graphene interface could be modulated. The MoS₂ FETs with Au/Ti-graphene electrodes exhibited enhanced on/off ratios (~10² times) and electron mobility (~2.5 times) compared to the MoS₂ FETs with Au/Ti electrodes. These results could improve the understanding of desirable contact formation for high-performance MoS₂ FETs and provide a facile route for viable electronic applications.