Metal-Insulator Transition and Charge Transport mechanisms in SnSe2 Field Effect Transistor

We report an observation of metal-insulator transition in a thin film of SnSe2. The room-temperature carrier concentration of SnSe2 film was increased by electrostatic doping to 1.14× 1013 cm−2. A crossover from insulating phase to metallic state was clearly observed. The low-temperature charge transport mechanism is governed by two-dimensional(2D) variable-range hopping. This mechanism is influenced by band bending and gap states introduced by seleniumvacancies. At low temperatures, the mobility is primarily limited by charged impurities, while at higher temperatures, itfollows a power-law dependence, μ = T−γ , indicating a dominance of electron-phonon scattering. The application of agate field shifts the Fermi level toward the conduction band, and at sufficiently high temperatures, this drives the systeminto a metallic state. Our findings offer insights into the charge transport mechanisms in SnSe2 FET, this understandingwill allow for the optimization of other 2D materials for advanced electronic device applications.