Experimental and modeling study of 1/f noise in multilayer MoS_2 and MoSe_2 field-effect transistors

摘要

In field-effect transistors (FETs) with two-dimensional (2D) transition metal dichalcogenide channels, the dependence of field-effect mobility on atomic layer thickness has been studied and interpreted in terms of interface scattering and interlayer coupling resistance (R_(int)). However, a model for 1/f noise, such as in MoS_2 and in MoSe_2 FETs, for various contact metals and layer number thicknesses has not been reported. In this work, we have experimentally studied current-voltage and 1/f noise on MoS_2 and MoSe_2 FETs with source and drain contacts of high and low work function metals to understand both the mobility and the noise behavior. We have developed a noise model incorporating layer number dependent Hooge parameters and R_(int). The noise and mobility models utilize screening lengths for charge, mobility, and Hooge parameter to describe the variation of these quantities with a layer number. Using our single model topology with appropriate fitting parameters for each material and each contact metal, the model captures the experimentally observed layer thickness dependence of the Hooge parameter. Our noise analysis is fully comprehensive and, hence, could be applied to any 2D layered systems.