Gate-Controlled Metal-Insulator Transition in TiS 3 Nanowire Field-Effect Transistors.

We explore the electrical characteristics of TiS nanowire field-effect transistor (FETs), over the wide temperature range from 3 - 350 K. These nanomaterials have a quasi-one-dimensional (1D) crystal structure and exhibit a gate-controlled metal-insulator transition (MIT) in their transfer curves. Their room-temperature mobility is 20 - 30 cm/Vs, two orders of magnitude smaller than predicted previously, a result that we explain quantitatively in terms of the influence of polar-optical phonon scattering in these materials. In the insulating state (< 220 K), the transfer curves exhibit unusual mesoscopic fluctuations, and a current suppression near zero bias that is common to charge-density wave (CDW) systems. The fluctuations have a non-monotonic temperature dependence, and wash out at a temperature close to that of the bulk MIT, suggesting they may be a feature of quantum interference in the CDW state. Overall, our results demonstrate that quasi-1D TiS nanostructures represent a viable candidate for FET realiztion, and that their functionality is influenced by complex phenomena.