Electron transport analysis in positional isomers - A DFT-NEGF approach

Abstract Molecular electronics is believed to be the possible solution to the problem of miniaturization of conventional silicon-based electronics. Since various quantum effects occur in this regime, it is vital to understand the transport properties of organic molecules. The electron transport properties of 4,6‐dibromobenzene‐1,3‐dithiol; 2,4‐dibromobenzene‐1,3‐dithiol and 2,5-dibromobenzene-1,3-dithiol molecules was analyzed using Density Functional Theory (DFT) with Non-Equilibrium Green's Function (NEGF). The density of states at zero bias of all these molecules more or less resemble the same nearby Fermi region. While increasing the bias, the bias window gets opened and the available density of states nearby Fermi region changes and produce nonlinearity in the current flow. The projected density of states was calculated to get an insight into the molecular contribution in electron transport. At higher bias, the dissimilarity between the forward and reverse bias transmission coefficient was observed. Due to this, rectification was present in these molecular junctions. Out of these molecular junctions, 2,4‐dibromobenzene‐1,3‐dithiol shows higher rectification ratio than 4,6-dibromobenzene-1,3-dithiol and 2,5-dibromobenzene‐1,3‐dithiol molecules.