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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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01 Jan 2013
TL;DR: In this paper, the authors demonstrate that single-layer graphene with a high density of Ag adatoms displays the unconventional phenomenon of negative quantum capacitance near the charge neutrality point (CNP).
Abstract: We demonstrate that single-layer graphene (SLG) decorated with a high density of Ag adatoms displays the unconventional phenomenon of negative quantum capacitance. The Ag adatoms act as resonant impurities and form nearly dispersionless resonant impurity bands near the charge neutrality point (CNP). Resonant impurities quench the kinetic energy and drive the electrons to the Coulomb energy dominated regime with negative compressibility. In the absence of a magnetic field, negative quantum capacitance is observed near the CNP. In the quantum Hall regime, negative quantum capacitance behavior at several Landau level positions is displayed, which is associated with the quenching of kinetic energy by the formation of Landau levels. The negative quantum capacitance effect near the CNP is further enhanced in the presence of Landau levels due to the magnetic-field-enhanced Coulomb interactions.
19 citations
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TL;DR: In this paper, a highly sensitive integrated capacitance bridge for quantum capacitance measurements was proposed, based on a GaAs HEMT amplifier, which achieved a resolution at room temperature of 10aF per root Hz for a 10mV AC excitation at 17.5 kHz, with improved resolution at cryogenic temperatures, for the same excitation amplitude.
Abstract: We have developed a highly-sensitive integrated capacitance bridge for quantum capacitance measurements. Our bridge, based on a GaAs HEMT amplifier, delivers attofarad (aF) resolution using a small AC excitation at or below kT over a broad temperature range (4K-300K). We have achieved a resolution at room temperature of 10aF per root Hz for a 10mV AC excitation at 17.5 kHz, with improved resolution at cryogenic temperatures, for the same excitation amplitude. We demonstrate the performance of our capacitance bridge by measuring the quantum capacitance of top-gated graphene devices and comparing against results obtained with the highest resolution commercially-available capacitance measurement bridge. Under identical test conditions, our bridge exceeds the resolution of the commercial tool by up to several orders of magnitude.
19 citations
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TL;DR: In this article, the authors reported joint first-principles/continuum calculations (JFPCCs) on a monolayer graphene electrode immersed in an electrolyte coupled with a reference electrode under an applied potential.
18 citations
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TL;DR: In this article, the current-voltage characteristics of ballistic carbon-nanotube field effect transistors are characterized with an iterative simulation program, where the influence of carbon nanotube chirality and diameter on the output current is considered.
Abstract: Current–voltage characteristics of ballistic carbon-nanotube field-effect transistors are characterized with an iterative simulation program. The influence of carbon-nanotube chirality and diameter on the output current is considered. An analytical current–voltage expression under the quantum capacitance limit and low-voltage application is derived. Our simulation results are compared with actual measurement data.
18 citations
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03 Dec 2010TL;DR: In this article, a simple phenomenological model for the quantum capacitance of bilayer graphene is presented, which is calculated from the broadened density of states taking into account electron-hole puddles and possible finite lifetime of electronic states through a Gaussian broadening distribution.
Abstract: We present a simple phenomenological model for the quantum capacitance of bilayer graphene. Quantum capacitance is calculated from the broadened density of states taking into account electron-hole puddles and possible finite lifetime of electronic states through a Gaussian broadening distribution. The obtained results are in agreement with many features recently observed in quantum capacitance measurements on gated bilayer graphene. The temperature dependence of quantum capacitance is also investigated.
18 citations