First-Principles Design of Ohmic FET Devices from 2D Transition Metal Dichalcogenides

A chlorine-doped ultrathin phase of hafnium disulfide (HfS2) is proposed as an ideal candidate material for 2D field-effect transistor (FET) device applications, down to the extreme sub-5 nm miniaturization limit. This transition metal dichalcogenide 2D material is designed to combine features of both a metal and a semiconductor, exhibiting a high electric conductivity comparable with ordinary metals, that can be abruptly cut down via gating due to an energy gap immediately below the Fermi level and its anomalous metallic properties. These unique features enable realizing an alternative design of a FET device in which electrode and channel are made of the same Cl-doped ML HfS2 phase, a potential breakthrough bypassing all issues associated with electronic (Schottky) and structural dis-homogeneities or low conductivity that have hindered progress in this field. This material/design combination shall lead to a FET device with purely ohmic behavior, high metallic conductance, no interfacial contact resistance, and facile gating with extremely high on/off ratio.