The intrinsic origin of hysteresis in MoS₂ field effect transistors

We investigate the hysteresis and gate voltage stress effect in MoS₂ field effect transistors (FETs). We observe that both the suspended and the SiO₂-supported FETs have large hysteresis in their transfer curves under vacuum which cannot be attributed to the traps at the interface between the MoS₂ and the SiO₂ or in the SiO₂ substrate or the gas adsorption/desorption effect. Our findings indicate that the hysteresis we observe comes from the MoS₂ itself, revealing an intrinsic origin of the hysteresis besides some extrinsic factors. The fact that the FETs based on thinner MoS₂ have larger hysteresis than that with thicker MoS₂ suggests that the surface of MoS₂ plays a key role in the hysteresis. The gate voltage sweep range, sweep direction, sweep time and loading history all affect the hysteresis observed in the transfer curves.