  Two-dimensional (2D) materials are particularly attractive to build the
channel of next-generation field-effect transistors (FETs) with gate lengths
below 10-15 nm. Because the 2D technology has not yet reached the same level of
maturity as its Silicon counterpart, device simulation can be of great help to
predict the ultimate performance of 2D FETs and provide experimentalists with
reliable design guidelines. In this paper, an ab initio modelling approach
dedicated to well-known and exotic 2D materials is presented and applied to the
simulation of various components, from thermionic to tunnelling transistors
based on mono- and multi-layer channels. Moreover, the physics of metal - 2D
semiconductor contacts is revealed and the importance of different scattering
sources on the mobility of selected 2D materials is discussed. It is expected
that modeling frameworks similar to the one described here will not only
accompany future developments of 2D devices, but will also enable them.
