Control of polarity in multilayer MoTe field-effect transistors by channel thickness.

In this study, electronic properties of field-effect transistors (FETs) fabricated from exfoliated MoTe single crystals are investigated as a function of channel thickness. The conductivity type in FETs gradually changes from n-type for thick MoTe layers (above ≈ 65 nm) to ambipolar behavior for intermediate MoTe thickness (between ≈ 60 and 15 nm) to p- type for thin layers (below ≈ 10 nm). The n-type behavior in quasi-bulk MoTe is attributed to doping with chlorine atoms from the TeCl transport agent used for the chemical vapor transport (CVT) growth of MoTe.