Electron transport via a few-dopant cluster in the presence of counter-dopants in silicon nanowire transistors

Electron transport through a few-donor cluster flanked by acceptors is studied by first-principles and semi-empirical simulations in gated Si-nanowire transistors with n + electrostatically-doped source/drain. Local density-of-states spectra are probed by electrical characteristics at room temperature for clarifying modifications induced by acceptor-atoms on the energy states of the few-donor cluster. It is found that acceptor-atoms located between the few-donor cluster and the leads mainly shift the cluster potential, introducing a minor distortion to its energy spectrum. The results change only weakly as the acceptor-atoms are moved towards the Si nanowire surface, and systematically depend on the number of acceptors.