Employing poly(4-vinylpyridine) as the dielectrics for enhanced molybdenum disulfide field-effect transistors

Herein, field-effect transistors (FET) based on multilayer molybdenum disulfide (MoS${}_2$) nanoflakes are fabricated by employing poly(4-vinylpyridine) (PVP) as the modified layer of typical inorganic dielectric (SiO${}_2$). The MoS${}_2$ nanoflakes are directly exfoliated from bulk MoS${}_2$ and transferred onto the PVP surface instead of bare SiO${}_2$ 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 MoS${}_2$ bulk crystal may be achieved that is responsible for the large-size MoS${}_2$ nanoflakes (≈2.5 × 10${}^5$ µm${}^2$). Importantly, MoS${}_2$ FETs based on the double-gate insulators consisting of PVP and SiO${}_2$ 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 (Φ${}_{SB}$). The current studies will effectively push the applications of MoS${}_2$ nanoflakes in flexible electronics. (© 2022 Wiley‐VCH GmbH)