Modeling of Electron Devices Based on 2-D Materials

Abstract

The advent of graphene and related two-dimensional (2D) materials has attracted the interest of the electron device research community in the last fourteen years. The possibility to boost transistor performance and the prospects to build novel device concepts with 2D materials and their heterostructures has awakened a strong experimental interest that requires continuous support from modeling. In this paper we review the state of the art in simulation of electron devices based on two-dimensional materials. We outline the main methods to model the electronic bandstructure and to study electron transport, classifying them in terms of accuracy and computational cost. We briefly discuss how they can be combined in a multiscale approach to provide quantitative understanding of the mechanisms determining the operation of electron devices and we examine the application of these methods to the different families of 2D materials. Finally we shortly analyze the main open challenges of modeling 2D-based electron devices.

Tunnel-Field-Effect Spin Filter from Two-Dimensional Antiferromagnetic Stanene

“…For the DFT calculations, a space of 32Å and 20Å of vacuum in the direction of the nanoribbon width and the direction orthogonal to the nanoribbon plane, respectively, are assumed to minimize the interaction between periodic repetitions of the cell. We have performed a structural optimization within the Broyden-Fletcher-Goldfarb-Shanno algorithm until forces were smaller than 5 × 10 −3 eV/Å with a convergence threshold for energy of 10 scheme [55,56]. To this purpose, we have projected the plane-wave DFT basis set into a Maximally Localized Wannier Functions (MLWF) basis set, exploiting Wannier90 code [57], resulting in Hamiltonians of 96 nearest-neighbors for both spin-up and spin-down states.…”

Lateral Heterostructure Field-Effect Transistors Based on Two-Dimensional Material Stacks with Varying Thickness and Energy Filtering Source

“…We have adopted a multiscale simulation approach combining different levels of physical abstraction, ranging from ab initio calculations of materials properties to full device simulations based on coherent quantum transport. 30 We have calculated the electronic band-structure of monolayer and bilayer PdS 2 , PtS 2 , and NiS 2 using density functional theory (DFT) as implemented in the Quantum Espresso suite 31 (see Methods ). The strong dependence of the electronic structure on the number of layers is highlighted in Figure 1 a: When the crystal structure is varied from monolayer to bilayer, PdS 2 and NiS 2 undergo a phase change from semiconductor to semimetal, whereas PtS 2 has its energy gap reduced from 1.59 to 0.48 eV.…”

High-Performance Two-Dimensional InSe Field-Effect Transistors with Novel Sandwiched Ohmic Contact for Sub-10 nm Nodes: a Theoretical Study

“…The channel and its two interfaces with active regions were additionally relaxed with fixed source and drain. All simulations were based on non-equilibrium Green’s function (NEGF) theory and carried out by QuantumATK with fully self-consistent calculation [34–36], which was usually employed to design and investigate transistors at sub-10 nm nodes [17, 37–39]. Double-zeta polarized basis set were employed with mech-cut off of 90 Rydberg.…”

“…The SB at the active regions yields large contact resistance, and low doping level further degrades current density. Achieving low contact resistance with sufficiently doped active regions has become the main limiting factor for 2D materials-based FET (2D FET) to achieve high performance [17–19].…”