Nanoscale Dielectric Capacitors Composed of Graphene and Boron Nitride Layers: A First Principles Study of High-Capacitance at Nanoscale

摘要

We investigate a nanoscale dielectric capacitor model consisting oftwo-dimensional, hexagonal h-BN layers placed between two commensurate andmetallic graphene layers using self-consistent field density functional theory.The separation of equal amounts of electric charge of different sign indifferent graphene layers is achieved by applying electric field perpendicularto the layers. The stored charge, energy, and the electric potential differencegenerated between the metallic layers are calculated from the first-principlesfor the relaxed structures. Predicted high-capacitance values exhibit thecharacteristics of supercapacitors. The capacitive behavior of the presentnanoscale model is compared with that of the classical Helmholtz model, whichreveals crucial quantum size effects at small separations, which in turn recedeas the separation between metallic planes increases.