On the mobility and contact resistance evaluation for transistors based on MoS2 or two-dimensional semiconducting atomic crystals

Abstract

Contact resistance (Rc) can substantially obscure the extracted mobility based on standard transconductance or two-point conductance measurements of field-effect devices especially for low density of states materials such as MoS2 or similar atomic crystals. Currently, there exists a pressing need for a routine technique that can decouple mobility extraction from Rc. By combining experiments and analysis, we show that the Y-function method offers a robust route for evaluating the low-field mobility, threshold voltage and Rc even when the contact is a Schottky-barrier as is common in two-dimensional transistors. In addition, an independent modified transfer length method evaluation corroborates the Y-function analysis.