Thickness-dependent carrier polarity of MoTe2 transistors with NiTe2 semimetal contacts.

We demonstrated that the carrier polarity of MoTe₂ transistors can be modulated by controlling the channel thickness with NiTe₂ semimetal contacts. The multilayer MoTe₂ transistors (thickness >7.1 nm) exhibit a symmetric ambipolar conduction, and a transition to unipolar p-type polarity occurs as the channel thickness decreased down to ∼2.3 nm. The position of the semimetal NiTe₂ work function was verified to be located at the mid-gap of multilayer MoTe₂, and the observed transition was interpreted by a synergistic effect of the channel thickness-dependent band alignment and charge transfer behavior with unique NiTe₂ semimetal contacts. [ABSTRACT FROM AUTHOR]