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Quantum capacitance
About: Quantum capacitance is a research topic. Over the lifetime, 954 publications have been published within this topic receiving 24165 citations.
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TL;DR: In this paper, the problem of electrostatic screening of a charged line by undoped or weakly doped graphene is treated beyond the linear-response theory, and the induced electron density is found to be approximately doping independent, at intermediate distances $x$ from the charged line.
Abstract: The problem of electrostatic screening of a charged line by undoped or weakly doped graphene is treated beyond the linear-response theory. The induced electron density is found to be approximately doping independent, $n(x)\ensuremath{\sim}{x}^{\ensuremath{-}2}{log}^{2}x$, at intermediate distances $x$ from the charged line. At larger $x$, twin $p\text{\ensuremath{-}}n$ junctions may form if the external perturbation is repulsive for graphene charge carriers. The effect of such inhomogeneities on conductance and quantum capacitance of graphene is calculated. The results are relevant for transport properties of graphene grain boundaries and for local electrostatic control of graphene with ultrathin gates.
4 citations
TL;DR: A short overview of quantum capacitance can be found in this paper, with a review of some recent developments and some tantalizing recent physical revelations about quantum capacitabilities, such as the fact that quantum capacitation can posses a negative value, hence allowing for the possibility of enhancing the overall capacitance in some particular material systems.
Abstract: All materials (including conductors) possess the so-called quantum capacitance, which is present in series with the traditional geometric (electrostatic) capacitance. It is usually a large positive quantity and therefore irrelevant for most materials except for nanostructures. Quantum capacitance has been found to reduce the overall capacitance of nanostructures compared with what is predicted by classical electrostatics. One of many tantalizing recent physical revelations about quantum capacitance is that it can posses a negative value, hence, allowing for the possibility of enhancing (sometimes dramatically) the overall capacitance in some particular material systems—beyond the scaling predicted by classical electrostatics. We provide here a short overview of this subject and review some recent developments.
4 citations
10 Apr 2014
TL;DR: In this article, the effect of changing the width of a nanoribbon's width on the band gap energy has been analyzed using a variation of width method and the results showed that a compromise of between width of GNR and capacitance is the better designing of a GNR based device in nanotechnology.
Abstract: Graphene nanoribbon (GNR) relinquishes the zero band gap technology provides the promising candidates in electronic conduction. Lessening the width in nano scale as a ribbon creates considerable bandgap. The effect of changing the width of GNR, classical capacitance follows the linear curve need higher analysis of quantum capacitance in different regime using variation of width method. Persistence of quantum phenomena is observed through comparison of quantum capacitance and classical capacitance in nano scale device. In this paper at first we will observe the band gap energy for varying GNR's width. We will also calculate classical capacitance by varying again GNR's width. But classical capacitance does not give full information when electron goes through GNR channel. For this we will calculate a capacitance formed in GNR by varying GNR's width called quantum capacitance considering two regime named as degenerate and nondegenerate regime. From this we will get information that among classical capacitance, quantum capacitance in degenerate and nondegenerate regime which one dominates or is dominated over another. Upon this a compromise of between width of GNR and capacitance is the better designing of GNR based device in nanotechnology.
4 citations
TL;DR: In this paper, a small asymmetry in the Fermi velocity of electrons and holes in graphene was found, which can be verified by Landau level spectroscopy and quantum capacitance measurements of bi-axially strained graphene.
Abstract: Using full-potential density functional theory (DFT) calculations, we found a small asymmetry in the Fermi velocity of electrons and holes in graphene. These Fermi velocity values and their average were found to decrease with increasing in-plane homogeneous biaxial strain; the variation in Fermi velocity is quadratic in strain. The results, which can be verified by Landau level spectroscopy and quantum capacitance measurements of bi-axially strained graphene, promise potential applications in graphene based straintronics and flexible electronics.
4 citations
TL;DR: In this article, the authors presented a computationally efficient physics-based compact model for the Schottky barrier CNTFET, which captured a number of features exhibited by these transistors such as ballistic transport and channel potential variation with respect to channel charge.
Abstract: This paper presents a computationally efficient physics-based compact model for the Schottky barrier CNTFET. This compact model captured a number of features exhibited by these transistors such as ballistic transport and channel potential variation with respect to channel charge. Also quantum capacitance is pointed out. A new analytical model of the channel charge is presented here. The compact model accuracy is verified within its range of validity. To investigate on the SB influence, two classical circuit applications are simulated; the logical inverter and the 5 stages ring oscillator (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
4 citations