First-principles study of nonclassical effects in silicon-based nanocapacitors

Abstract

Properties of silicon-based nanocapacitor are studied from first principles. The nanocapacitor consists of electrodes of the silicon-based material planar polysilane. Nonclassical effects are analyzed by changing both the electrode spacing and the applied bias simultaneously. Even when the electrode spacing is fixed, the effective electrode spacing decreases with applied bias because of the quantum capacitance effect. In addition, when the electrostatic capacitance is analyzed in detail, it is also found that the effective electrode surface changes complicatedly with electrode spacing and applied bias because of the dielectric polarization effect of the electrode material. The dielectric polarization effect is one order of the magnitude smaller than the quantum capacitance effect, which is due to the nature of the electrode material, planar polysilane. It is clarified that a nanocapacitor is governed by the detailed properties of the electronic states of the electrode materials as well as the geometry.