Ballistic quantum transport in nano devices and circuits

Abstract

Ohm's law, a linear current-voltage pattern, has been and continues to be the basis for characterizing, evaluating performance, and designing integrated circuits, but is shown not to hold its supremacy as channel lengths are being scaled down. In a nanoscale circuit with reduced dimensionality in one or more of the three Cartesian directions, quantum effects transform the carrier statistics. In the high electric field, the collision free ballistic transform is predicted, while in low electric field the transport remains predominantly scattering-limited. In a muro/nano-circuit, even a low logic voltage of 1 V is above the critical voltage Vc (V>>Vc) triggering nonohmic behavior that results in ballistic current saturation. The saturation current is now controlled by ballistic (B) saturation velocity that is comparable to an appropriate thermal velocity for a nondegenerate and Fermi velocity for a degenerate system with given dimensionality. A quantum emission may lower this ballistic velocity. A review of the physics behind breakdown of Ohm's law and existence of quantum effects in engineering low-dimensional nanoelectronic devices is given.