Towards realistic atomic-scale modeling of nanoscale devices

On the nanoscale, electrical currents behave radically different compared to on the microscale. As the active regions become comparable to or smaller than the mean-free path of the material, it becomes necessary to describe the electron transport by quantum-mechanical methods instead of using classical relations like Ohm's law. Over the past decade, methods for computing electron tunneling currents in nanosized junctions have evolved steadily, and are now approaching a sophistication where they can provide real assistance in the development of novel semiconductor materials and devices. At the same time, the industry's demand for such solutions is rising rapidly to meet the challenges both above and under the 16 nm node. In this paper we provide an overview of the current state-of-the-art of the field of how to model electrical currents on the nanoscale, using atomic-scale simulations.