Threshold Voltage Control through Solvent Doping of Monolayer MoS<sub>2</sub> Transistors.

Neilson, Kathryn; Mokhtarzadeh, Charles; Jaikissoon, Marc; Bennett, Robert K A; Buragohain, Pratyush; Verma Penumatcha, Ashish; Kumar Pinnepalli, Sai Siva; Rogan, Carly et al. · Nano Lett · 2025

basic_science · Level V

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Abstract

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 (<i>V</i><sub>T</sub>), while retaining switching behavior. In this work, we explore n-doping monolayer MoS<sub>2</sub> with solvents of varying polarity to both enhance transistor performance and understand how solvents impact the <i>V</i><sub>T</sub>. We find that solvent polarity predictably shifts the <i>V</i><sub>T</sub> when states are available near the MoS<sub>2</sub> conduction band. This n-doping shifts the <i>V</i><sub>T</sub>, 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 <i>V</i><sub>T</sub> shifting and offer clarity on the role solvents play in processing 2D devices.