Drain induced barrier increasing in multilayer ReS₂

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 (ReS₂) as a possible reverse short channel effect (rSCE). The reported decoupled layer interaction and much higher interlayer resistivity of ReS₂ 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 ReS₂, 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.