Contact optimisation strategy for wafer-scale field-effect transistors based on two-dimensional semiconductors

Two-dimensional(2D)semiconductors can be utilized to continually miniaturize nanoscale electronic de-vices.However,achieving a practical solution for satisfying electrical contact with 2D semiconductors remains challenging.In this study,we developed a novel contact structure with transferred multilayer(t-ML)MoS 2 by integrating both edge and top contact.After in-situ plasma treatment for the edge of the MoS 2 channel and successive metal deposition,we achieved 16 times lower contact resistivity(22.8 kΩμm)than that of the top contacted devices.The thickness-dependent electrical measurement indicates that edge contact is highly effective with thick MoS 2 due to the alleviated current-crowding effect re-sulting from the small contact area.The temperature-dependent transport measurement further confirms the effective minimization of the influence from the Schottky barrier and tunnelling barrier.Finally,the simplified resistor network model and energy-band diagram were proposed to understand the carrier transport mechanism.Our work provides a practical strategy for achieving excellent electrical contact between bulk metals and 2D semiconductors,paving the way for future large-scale 2D electronic devices.