Electrical characterization of multilayer HfSe2 field-effect transistors on SiO2 substrate

We fabricated and characterized two-dimensional field-effect transistors (FETs) based on hafnium diselenide (HfSe2) crystalline nanoflakes. The HfSe2 FET exhibits an n-type semiconductor behavior with a high on/off current ratio exceeding 7.5 × 106. In the temperature range of 120 K–280 K, the thermally activated transport is observed at high carrier concentrations, while at low concentrations and low temperatures hopping conduction dominates the transport mechanism. We also observed the metal insulator transition at carrier density of ∼1.8 × 1012 cm−2. This initial report on the physical and electrical characterization of two dimensional HfSe2 material demonstrates the feasibility of this semiconducting material for electronic devices.