Electron transport properties of molecular devices based on silicon-1, 6-hexanedithiol-silicon

Abstract

To reveal how the electronic transport properties of the silicon-sulfur molecular junction depend on its microscopic structure, we studied the configuration and electronic transport properties of a silicon-1, 6-hexanedithiol-silicon molecular device, based on density functional theory (DFT) combined with the non-equilibrium Green’s function (NEGF) method. Eight groups of molecular junctions were modeled, each consisting of a 1, 6-hexanedithiol molecule spanning two silicon tips. Following optimisation of the molecular structure, first of the 1, 6-hexanedithiol by itself and then of the junction as a whole, the zero-bias conductance and electronic transmission spectrum were calculated. The results show that silicon-sulfur molecular junctions have characteristics that differ significantly from those of gold-sulfur molecular junctions. The structural details of the silicon-sulfur molecular junction are shown to have a crucial influence on its electronic transport properties such as zero-bias piezoelectric conductance and transmission spectra.