Thickness Dependence of Low-Frequency Noise in MoS2 Field-Effect Transistors With Enhanced Back-Gate Control
Low-frequency noise has become one of the major limitations on further exploration for the ultimate performance of nanoelectronic devices based on novel two-dimensional (2D) materials. Here, the low-frequency 1/<inline-formula> <tex-math notation="LaTeX">${f}$ </tex-math> </inline-formula> noise has been qualitatively investigated on MoS<sub>2</sub> field-effect transistors (FETs) with different layer numbers. 1/<inline-formula> <tex-math notation="LaTeX">${f}$ </tex-math> </inline-formula> noise in multi-layer (2-layer and thicker) MoS<sub>2</sub> devices follows the Hooge mobility fluctuation model. But for monolayer MoS<sub>2</sub> FET, 1/<inline-formula> <tex-math notation="LaTeX">${f}$ </tex-math> </inline-formula> noise is dominated by the carrier number fluctuation model in a weak accumulation regime, while the mobility fluctuation model is the dominant source in a strong accumulation regime. Such 1/<inline-formula> <tex-math notation="LaTeX">${f}$ </tex-math> </inline-formula> noise characteristics are explained with the depth of intrinsic defect trap energy levels in MoS<sub>2</sub> thin films through first-principle calculation and the enhanced gate control by using engineered back-gate stack.