Analysis of Hysteresis Observed in Multi-Layered MoS2 Field Effect Transistors

To implement a field effect transistor with multi-layered MoS2 (hereafter denoted as MoS2 FET), many practical problems need to be overcome, such as the hysteresis generation of the devices. In order to clarify further the origin of the hysteresis observed in the transfer characteristics of the MoS2 FET, we analyzed the capacitance-voltage (C-V) characteristics of the MoS2 capacitor. The MoS2 capacitor can overcome the effect of the adsorbed molecules (e. g., water molecules) on the hysteresis generation. Based on both the arguments presented in previous works for the role of sulfur vacancy in MoS2 and the hysteresis characteristics of the MoS2 capacitor observed in the current work, we suggest a model for the donor-like interface traps that originated from the sulfur vacancy defects at the SiO2/MoS2 interface to determine the origin of hysteresis generation in MoS2 FET. We further argue that the energy level of donor-like interface traps is mainly localized below the mid-band gap, which explains the asymmetrical increase of hysteresis depending on the direction of gate sweep voltage.