Two-dimensional (2D) materials have interested researchers all over the world for years due to their unique properties. Their ultra-thin thicknesses, lack of dangling bonds, and excellent thermal stabilities make them promising material candidates for use in next generation nanoelectronic devices. Graphene was the first 2D material discovered and has extremely high carrier mobility (>10^5 cm^2/V-sec). However, it lacks a finite band gap, restricting its potential use in field-effect transistors (FETs) to only the channel. Alternatively, MoS2 is a compound 2D material with a finite band gap and low dielectric constant. As a result, it has recently been generating great interest in both academia and industry for its potential use in switchable devices.

In this work, we have explored the interface states that form between the channel of a monolayer MoS2 transistor and a high-k gate dielectric. These interface states result in a large hysteresis in the transfer characteristic (i.e. drain current versus gate voltage) of the transistor. By applying carefully designed pulses to the gate of the transistor, we show that it is possible to both understand the nature of the interface states and minimize the hysteresis. This allows for reliable extraction of material parameters such as mobility from the transfer characteristics.





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