Ternary transition metal chalcogenide Nb${}_2$Pd${}_3$Se${}_8$. A new candidate of 1D van der Waals materials for field-effect transistors

In this work, high-quality 1D van der Waals (vdW) Nb${}_2$Pd${}_3$Se${}_8$ is synthesized, showing an excellent scalability from bulk to single-ribbon due to weakly bonded repeating unit ribbons. The calculation of electronic band structures confirmed that this novel Nb${}_2$Pd${}_3$Se${}_8$ is a semiconducting material, displaying indirect-to-direct bandgap transition with decreasing the number of unit-ribbons from bulk to single. Field effect transistors (FETs) fabricated on the mechanically exfoliated Nb${}_2$Pd${}_3$Se${}_8$ nanowires exhibit n-type transport characteristics at room temperature, resulting in the values for the electron mobility and I${}_{on}$/I${}_{off}$ ratio of 31 cm${}^2$ V${}^{-1}$ s${}^{-1}$ and $\approx$10${}^4$, respectively. Through transport measurements at various temperatures from room temperature down to 90 K, it is confirmed that Nb${}_2$Pd${}_3$Se${}_8$ FETs can achieve negligible Schottky barrier height (SBH) for the Au contacts at the temperature range, displaying clear ohmic contact characteristics. Furthermore, top-gated FETs fabricated with the Al${}_2$O${}_3$ dielectric layer are studied simultaneously with back-gated FETs. (© 2021 Wiley‐VCH GmbH)