  2D materials are expected to be favorable channel materials for field-effect
transistor (FET) with extremely short channel length because of their superior
immunity to short-channel effects (SCE). Graphene, which is the most famous 2D
material, has no bandgap without additional techniques and this property is
major hindrance in reducing the drain leakage. Therefore, 2D materials with
finite band gap, such as transition metal dichalcogenides (TMDs, e.g. MoS2
WSe2) or phosphorene, are required for the low power consumption FETs. Hafnium
disulfide (HfS2) is a novel TMD, which has not been investigated as channel
material. We focused on its potential for well-balanced mobility and bandgap
properties. The higher electron affinity of Hf dichalcogenides compared with Mo
or W chalcogenides facilitates the formation of low resistance contact and
staggered heterojunction with other 2D materials. Here we demonstrate the first
few layer HfS2 FET with robust current saturation and high current on/off ratio
of more than 10^4.
