We investigate the impact of different substrates on the performance of a monolayer MoS 2 field-effect transistor (FET) by calculating the interface charge density between the MoS 2 layer and the substrate using first-principle calculations based on density functional theory to provide details about the overlap of electron orbitals at the interface. The electrical characteristics of the monolayer MoS 2 FET are determined by using the extracted interface charge density in numerical simulations. The electron transport behavior of the monolayer MoS 2 FET is modeled using the nonequilibrium Green’s function with mode space (NEGF_MS) approach. We study and compare the performance of monolayer MoS 2 FETs on different substrates, viz. SiO 2 , HfSiO 4 , Si 3 N 4 , HfO 2 , and h-BN. The results reveal that the monolayer MoS 2 FET on the h-BN/Si substrate exhibits an on-current of 548 µA/µm and a subthreshold swing of 65 mV/dec. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.