Lateral graphene/MoS2 heterostructures for steep-slope Dirac-source field-effect transistors

Based on first-principles calculations and quantum transport simulations, we systematically study the transport properties of n-type Dirac-source transistors based on lateral graphene/MoS2 2 heterostructures. Through manipulation of the graphene source doping concentration, we achieve a steep subthreshold swing (SS) of 48 mV/decade in the graphene/MoS2 2 lateral heterostructure Dirac-source transistor, while maintaining an ON-state current of 456.718 mu A/mu m, / mu m, meeting the [International Technology Roadmap for Semiconductors 2013 ed., https://www.semiconductors.org/resources/2013] requirements for low-power devices. Our analysis reveals that too high or too low source doping concentrations are detrimental to both SS and ON-state currents due to unfavorable band alignments at the graphene/MoS2 2 interface. Additionally, we observe a dual effect of interface states on device performance. The interface Schottky barrier (SB) is slightly decreased from the OFF state to the ON state due to the pinning of the interface states, and the increase of the current is attributed to the thinning of the SB. On the other hand, interface states shorten the tunneling path through the triangular SB at the ON state, thereby enhancing the ON-state currents. Finally we summarize the working mechanism of lateral heterostructure Dirac-source transistors. Our calculations can serve as a theoretical guide for designing Dirac-source transistors with both steep SS and large ON-state currents based on two-dimensional lateral heterostructures.