Employing Poly(4-Vinylpyridine) as the Dielectrics for Enhanced Molybdenum Disulfide Field-Effect Transistors

Herein, field-effect transistors (FET) based on multilayer molybdenum disulfide (MoS2) nanoflakes are fabricated by employing poly(4-vinylpyridine) (PVP) as the modified layer of typical inorganic dielectric (SiO2). The MoS2 nanoflakes are directly exfoliated from bulk MoS2 and transferred onto the PVP surface instead of bare SiO2 substrate that renders the enlarged nanoflake size. Taking advantage of the high surface energy and low surface roughness of PVP surface, the enhanced interaction between PVP and MoS2 bulk crystal may be achieved that is responsible for the large-size MoS2 nanoflakes (approximate to 2.5 x 10(5) mu m(2)). Importantly, MoS2 FETs based on the double-gate insulators consisting of PVP and SiO2 exhibit improved device performances. The on-state current presents a fivefold increase and the field-effect mobility is improved from 4.75 to 167.79 cm(2) Vs(-1), which are attributed to the PVP surface with low charge-trap states and the lowered Schottky Barrier height (phi(SB)). The current studies will effectively push the applications of MoS2 nanoflakes in flexible electronics.