Effect of interlayer tunneling barrier on carrier transport and fluctuation in multilayer ReS₂

Multilayer rhenium disulfide (ReS2) has recently attracted significant attention because of the decoupled van der Waals interaction between its adjacent layers that leads to a much higher interlayer resistivity than that in other layered materials. Although the carrier transport in multilayer materials is well described by the interlayer resistance and Thomas-Fermi charge screening length (λ) in theoretical resistor network models, the understanding of the effect of electric field-dependent interlayer tunneling barrier (Eint) on current fluctuation in two-dimensional (2D) multilayer materials is limited. Herein, we report the effects of Eint on carrier transport and charge fluctuation in multilayer ReS2. The electrostatic back-gate (VBG)- and drain bias (VD)-dependent Eint causes channel migration along the c-axis in 2D multilayer systems and consequently results in two plateaus in the transconductance curve, thereby allowing us to determine the top and bottom carrier mobilities of multilayer ReS2 separately. Furthermore, the strong correlation between Eint and the Coulomb scattering parameter in multilayer ReS2 is elucidated via low-frequency noise spectroscopy. The results of our study provide a clear insight into the origins of carrier transport and current fluctuation in 2D multilayer devices.