First-principles simulations of nanoscale transistors

We describe the transport characteristics of a 50 nm (gate length) 2D InAs tunnel field-effect n-i-n transistor in a double-gate fin-like geometry (fin width 2.3 nm) by means of atomic-scale simulations. In particular, we compare results from density functional theory (DFT) using the Meta-GGA exchange correlation potential with those from a tight-binding Hamiltonian. For the first time we show that the two methods give comparable results, proving the predictive power of atomic-scale simulations for this type of devices, and that it is possible to accurately study realistic ultrascaled devices with first-principles methods.