Electronic transport in Si:P δ-doped wires

Despite the importance of Si:P $\ensuremath{\delta}$-doped wires for modern nanoelectronics, there are currently no computational models of electron transport in these devices. In this paper we present a nonequilibrium Green's function model for electronic transport in a $\ensuremath{\delta}$-doped wire, which is described by a tight-binding Hamiltonian matrix within a single-band effective-mass approximation. We use this transport model to calculate the current-voltage characteristics of a number of $\ensuremath{\delta}$-doped wires, achieving good agreement with experiment. To motivate our transport model we have performed density-functional calculations for a variety of $\ensuremath{\delta}$-doped wires, each with different donor configurations. These calculations also allow us to accurately define the electronic extent of a $\ensuremath{\delta}$-doped wire, which we find to be at least 4.6 nm.