Thermally activated trap charges responsible for hysteresis in multilayer MoS₂ field-effect transistors

Hysteresis, which is induced by both extrinsic and intrinsic causes, is often observed in molybdenum disulphide (MoS₂) field-effect transistors (FETs), and several extrinsic hysteresis effects have been reported in unpassivated bottom-gate MoS₂ device structures. In this study, interface-trap-induced hysteresis and other electrical properties are examined. We experimentally investigate thermally activated trap charges near a silicon-dioxide (SiO₂)-MoS₂ interface that gives rise to hysteresis in a multilayer MoS₂ FET in a temperature region of 10-300 K. The threshold voltage (V_TH) and field-effect mobility (μ_FE) decrease with the increase in temperature, regardless of the gate-bias sweep direction. The hysteresis that coincides with the trend of subthreshold swing increases sharply above T = 150 K as the released charges from interface traps become dominant over the fixed charges. Based on a temperature-dependent hysteresis analysis, we discussed the activation energy of interface traps and maximum interface trap density of the fabricated multilayer MoS₂ FET.