micromachines Review 2D Electronics Based on Graphene Field Effect Transistors: Tutorial for Modelling and Simulation Bassem Jmai † , Vitor Silva † and Paulo M. Mendes *   Citation: Jmai, B.; Silva, V.; Mendes, P.M. 2D Electronics Based on Graphene Field Effect Transistors: Tutorial for Modelling and Simulation. Micromachines 2021, 12, 979. https://doi.org/10.3390/ mi12080979 Academic Editor: Ha Duong Ngo Received: 28 July 2021 Accepted: 16 August 2021 Published: 18 August 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). CMEMS-UMinho, University of Minho, 4800-058 Guimarães, Portugal; bassem.jmai@fst.utm.tn (B.J.); vitor.silva@inl.int (V.S.) * Correspondence: paulo.mendes@dei.uminho.pt † These authors contributed equally to this work. Abstract: This paper provides modeling and simulation insights into field-effect transistors based on graphene (GFET), focusing on the devices’ architecture with regards to the position of the gate (top-gated graphene transistors, back-gated graphene transistors, and top-/back-gated graphene transistors), substrate (silicon, silicon carbide, and quartz/glass), and the graphene growth (CVD, CVD on SiC, and mechanical exfoliation). These aspects are explored and discussed in order to facilitate the selection of the appropriate topology for system-level design, based on the most common topologies. Since most of the GFET models reported in the literature are complex and hard to understand, a model of a GFET was implemented and made available in MATLAB, Verilog in Cadence, and VHDL-AMS in Simplorer—useful tools for circuit designers with different backgrounds. A tutorial is presented, enabling the researchers to easily implement the model to predict the performance of their devices. In short, this paper aims to provide the initial knowledge and tools for researchers willing to use GFETs in their designs at the system level, who are looking to implement an initial setup that allows the inclusion of the performance of GFETs. Keywords: graphene field-effect transistors (GFETs); MATLAB; Verilog; VHDL-AMS; modeling 1. Introduction The development of CMOS (complementary metal-oxide semiconductor) transistors is achieving its performance limit, due to the maximum downscaling according to Moore’s law. Several new materials have appeared with the potential to overcome silicon devices’ performance; most of these rely on two-dimensional (2D) materials. Those families of materials feature dangling-bond free surfaces exhibiting excellent electronic and optical properties. Such materials range from graphene to other 2D materials, such as the transition metal dichalcogenides (TMDCs). TMDCs have a finite bandgap, which is essential to enable low-power digital electronics. The state of the art of the TMDC transistors and silicon transistors is similar, as reported in [1], where MoS 2 was used as the channel of the transistor, achieving an intrinsic maximum oscillation frequency (f max ) of 50 GHz at low temperatures. Despite the promising results at cryogenic temperatures, the FET mobility at room temperature remains low for TMDCs. Because of that, graphene (a monolayer of carbon atoms in a honeycomb lattice) is being widely pursued as an enabling material; it has amazing properties at room temperature, such as high saturation velocity and high carrier mobility, which make this material suitable for radiofrequency (RF) applications, for example. Since the discovery of graphene by Geim and Novoselov in 2004 [2], it continues to attract the interest of the scientific community, both for the prospects it offers in fundamen- tal research [3,4], and for applied physics [5,6]. Graphene is a 2D material, consisting of a sheet of carbon atoms arranged in a honeycomb lattice, weakly bonded to a supporting substrate [7]. The absence of a band gap in the band structure of graphene [8] is a serious obstacle for the development of digital applications based on this material (in contrast with Micromachines 2021, 12, 979. https://doi.org/10.3390/mi12080979 https://www.mdpi.com/journal/micromachines