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 the SnSe2 film was increased by electrostatic doping to 1.14×1013cm−2. A crossover from the insulating phase to the metallic state was clearly observed. The low-temperature charge transport mechanism is governed by two-dimensional variable-range hopping. This mechanism is influenced by band bending and gap states introduced by selenium vacancies. At low temperatures, the mobility is primarily limited by charged impurities, while at higher temperatures, it follows a power-law dependence, μ=T−γ, indicating a dominance of electron–phonon scattering. The application of a gate field shifts the Fermi level toward the conduction band, and at sufficiently high temperatures, this drives the system into a metallic state. Our findings offer insights into the charge transport mechanisms in SnSe2 field-effect transistor, this understanding will allow for the optimization of other 2D materials for advanced electronic device applications.