Electronic transport in Si:P delta-doped wires

TL;DR

This paper develops a nonequilibrium Green's function model for electron transport in Si:P delta-doped wires, validated by experimental current-voltage data and supported by density-functional calculations of electronic extent.

Contribution

It introduces the first computational transport model for Si:P delta-doped wires using NEGF and tight-binding Hamiltonian within a single-band approximation.

Findings

Good agreement between model and experimental I-V characteristics.

Delta-doped wires have an electronic extent of at least 4.6 nm.

Density-functional calculations inform the electronic structure of the wires.

Abstract

Despite the importance of Si:P 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 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 delta-doped wires, achieving good agreement with experiment. To motivate our transport model we have performed density-functional calculations for a variety of delta-doped wires, each with different donor configurations. These calculations also allow us to accurately define the electronic extent of a delta-doped wire, which we find to be at least 4.6 nm.