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/f noise has been qualitatively investigated on MoS2 field-effect transistors (FETs) with different layer numbers. 1/f noise in multi-layer (2-layer and thicker) MoS2 devices follows the Hooge mobility fluctuation model. But for monolayer MoS2 FET, 1/f noise is dominated by the carrier number fluctuation model in a weak accumulation regime, while the mobility fluctuationmodel is the dominant source in a strong accumulation regime. Such 1/f noise characteristics are explained with the depth of intrinsic defect trap energy levels in MoS2 thin films through first-principle calculation and the enhanced gate control by using engineered back-gate stack.