Atomistic Boron-Doped Graphene Field-Effect Transistors: A Route toward Unipolar Characteristics

摘要

We report fully quantum simulations of realistic models of boron-dopedgraphene-based field effect transistors, including atomistic details based onDFT calculations. We show that the self-consistent solution of thethree-dimensional (3D) Poisson and Schr"odinger equations with arepresentation in terms of a tight-binding Hamiltonian manages to accuratelyreproduce the DFT results for an isolated boron-doped graphene nanoribbon.Using a 3D Poisson/Schr"odinger solver within the Non-Equilibrium Green'sFunctions (NEGF) formalism, self-consistent calculations of the gate-screenedscattering potentials induced by the boron impurities have been performed,allowing the theoretical exploration of the tunability of transistorcharacteristics. The boron-doped graphene transistors are found to approachunipolar behavior as the boron concentration is increased, and by tuning thedensity of chemical dopants the electron-hole transport asymmetry can be finelyadjusted. Correspondingly, the onset of a mobility gap in the device isobserved. Although the computed asymmetries are not sufficient to warrantproper device operation, our results represent an initial step in the directionof improved transfer characteristics and, in particular, the developedsimulation strategy is a powerful new tool for modeling doped graphenenanostructures.