Operation and Design of Dirac-Source FETs Using Ab Initio Transport Simulations: Subthreshold Swing and Drive Current

This article investigates the operation and design of Dirac-source FETs (DSFETs), by using ab initio transport simulations based on the NEGF formalism, which seems appropriate given the novelty of the physics and of the device architecture introduced by DSFETs. In particular, we first discuss the limitations in terms of drive current of DSFETs based on a graphene-MoS<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> van der Waals heterojunction. Then, we propose a novel p-type DSFET based on hydrogenated graphene (HGr). Our simulation results suggest that the HGr-DSFET has a robust sub-60 mV/dec operation and an <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small>-current between <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times $</tex-math> </inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times $</tex-math> </inline-formula> larger than the graphene-MoS<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> DSFET counterpart. Our study investigates the influence on the device operation of several material and design parameters, using either ballistic simulations or simulations accounting for electron–phonon scattering.