Full-band study of ultra-thin Si:P nanowires

Metallic property and Ohmic conduction in densely phosphorus δ-doping ultra-thin silicon nanowires (Si:P NWs) are studied. A 10-band sp³ d⁵ s* tight-binding approach is used to describe device electronic structures atomistically. Electrostatics at equilibrium are self-consistently calculated with our in-house 3-D parallel Schrödinger-Poisson solver that is coupled to the Local Density Approximation to consider the electron exchange-correlation in simulations. We not only confirm the NW channel is metallic by calculating the equilibrium bandstructure of a 1.5nm wide and 1/4 atomic monolayer doping [110] Si:P NW, but also provide a strong connection to experiment by calculating ohmic conduction properties of a few NW channels and showing a quantitatively good agreement to the measured data. This work can be highlighted as the first study of Si:P NWs with a full-band atomistic approach.