Drain induced barrier increasing in multilayer ReS ₂

Abstract

Abstract The interlayer tunneling resistivity ( R int ) and Thomas-Fermi charge screening effects play critical roles in the carrier transport of two-dimensional (2D) multilayer devices. For example, the vertical electric field modifies the R int , resulting in a channel migration along the c -axis. However, because R int varies considerably with the drain electric field in addition to the vertical field, the effective contribution of each layer to the total current varies with the drain bias ( V D ). Here, we demonstrate a drain induced barrier increasing (DIBI) in 2D multilayer rhenium disulfide (ReS 2 ) as a possible reverse short channel effect (rSCE). The reported decoupled layer interaction and much higher interlayer resistivity of ReS 2 compared to other 2D materials allow us to observe the DIBI clearly. As V D increases, the effective amplitude of R int decreases dramatically, leading to (i) the increase of off-current, (ii) the enhancement of field-effect mobility, and (iii) the blue shift of the flat band voltage ( V FB ), which is in sharp contrast to a previous report on a short-channel bulk-Si device with drain induced barrier lowering (DIBL). We attribute this difference to the weakened Fermi level ( E F ) tunability when the channel migrates from the bottom to the top surface of ReS 2 , and to an opposite electrostatic force resulting from V D , implying the increased importance of V D -dependent R int in the carrier transport mechanism of 2D multilayer systems. The V D -dependent Coulomb scattering parameter probed via a low frequency (LF) noise analysis provides deeper insights for the channel shift. Our findings pave the way for understanding and exploiting the fundamental charge transport mechanism in 2D multilayer systems.