First-principles study of naphthalene-based single-electron transistor

Abstract

We have performed first-principle calculations based on density functional theory (DFT) and non-equilibrium greens functions (NEGF) for calculating the charging energies of molecular system weakly coupled to an environment. We apply this approach to the molecule naphthalene, which is lying flat on gate dielectric between the source and drain electrodes. Our calculated values of charging energy for naphthalene in an isolated case are in good agreement with experimental values. Further, in an electrostatic environment, the result shows renormalization of molecular energy levels and therefore reduces the charging energy of naphthalene. Subsequently, the charge stability diagram of naphthalene based single-electron transistor (SET) has been obtained by calculating the charging energies as a function of an external gate potential. This diagram shows the dependence of SET conductance on the gate voltage and the source-drain bias. Our implementation is intended to predict the charging energies of the naphthalene-based SETs that reveals further scope in realization of the devices at nanoscale.