Mobility overestimation in MoS${}_2$ transistors due to invasive voltage probes

Abstract

Improving carrier mobilities of two-dimensional (2D) semiconductors is highly sought after. Recently, Ng. et al. [1] reported rippled molybdenum disulfide (MoS${}_2$) transistors on bulged silicon nitride (SiN${}_x$) substrates that exhibit high electron mobilities up to ~900 cm${}^2$V${}^{-1}$s${}^{-1}$. The high mobility values were attributed to the suppression of electron-phonon scattering by the lattice distortion in the rippled MoS${}_2$ channel. While the results are compelling, this Matters Arising shows that the mobility values in ref. [1] are likely to be overestimated due to invasive voltage probes in the four-probe measurement setup, which causes a positive threshold voltage shift near the voltage probes and an artificial overestimation of apparent field-effect mobility.

6 pages, 2 figures