Threshold Voltage Control through Solvent Doping of Monolayer MoS₂ Transistors

Two-dimensional (2D) materials are promising for beyond-silicon logic due to their ultrathin bodies for atomically thin channels. A key challenge lies in doping, to enable high-performance devices with a predictable and tunable threshold voltage (V_T), while retaining switching behavior. In this work, we explore n-doping monolayer MoS₂ with solvents of varying polarity to both enhance transistor performance and understand how solvents impact the V_T. We find that solvent polarity predictably shifts the V_T when states are available near the MoS₂ conduction band. This n-doping shifts the V_T, increases the maximum on-current, and is achieved without significant degradation in the subthreshold swing. We also find that solvent doping reduces the Schottky barrier width, enabling a two-fold reduction in contact resistance. These findings provide a method to tune carrier concentrations by V_T shifting and offer clarity on the role solvents play in processing 2D devices.