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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: The quantum capacitance measured on few layer black phosphorus and its difference compared to that from conductance measurement is reported and provides guidelines for theoretical understanding and modeling of black phosphorus devices.
Abstract: The unique electrical, optical and thermal properties of black phosphorus have triggered the development of black phosphorus transistors as well as a wide range of other relevant applications. However, there are still challenges in understanding and modeling gated black phosphorus, among which the exploration of quantum capacitance is crucial. Understanding quantum capacitance requires specified measurements other than typical characterizations done before for black phosphorus transistors. Recently, Kuiri et al (Nanotechnology 26 485704) reported the quantum capacitance measured on few layer black phosphorus and its difference compared to that from conductance measurement. Localized states near the band edge were observed by the capacitance measurement, which was considered as the main reason for the difference. The new findings provide guidelines for theoretical understanding and modeling of black phosphorus devices.
3 citations
TL;DR: This work used a small coaxially gated carbon nanotube as a paradigmatical capacitor system and showed that quantum capacitance can be adjusted from very large positive to very large negative values, compared to the corresponding classical geometric value.
Abstract: Quantum capacitance is a fundamental quantity that can directly reveal many-body interactions among electrons and is expected to play a critical role in nanoelectronics. One of the many tantalizing recent physical revelations about quantum capacitance is that it can possess a negative value, hence allowing for the possibility of enhancing the overall capacitance in some particular material systems beyond the scaling predicted by classical electrostatics. Using detailed quantum mechanical simulations, we found an intriguing result that mechanical strains can tune both signs and values of quantum capacitance. We used a small coaxially gated carbon nanotube as a paradigmatical capacitor system and showed that, for the range of mechanical strain considered, quantum capacitance can be adjusted from very large positive to very large negative values (in the order of plus/minus hundreds of attofarads), compared to the corresponding classical geometric value (0.31035 aF). This finding opens novel avenues in designing quantum capacitance for applications in nanosensors, energy storage, and nanoelectronics.
3 citations
20 Aug 2021
TL;DR: In this article, the influence of magnetite concentration on energetic and electronic parameters of graphene/Fe3O4 composites is estimated using quantum chemical methods, and it is found that adding magnetite to pure graphene significantly changes its zone structure and capacitive properties.
Abstract: The outstanding mechanical and conductive properties of graphene and high theoretical capacity of magnetite make a composite based on these two structures a prospective material for application in flexible energy storage devices. In this study using quantum chemical methods, the influence of magnetite concentration on energetic and electronic parameters of graphene/Fe3O4 composites is estimated. It is found that the addition of magnetite to pure graphene significantly changes its zone structure and capacitive properties. By varying the concentration of Fe3O4 particles, it is possible to tune the capacity of the composite for application in hybrid and symmetric supercapacitors.
3 citations
23 Jun 2003
TL;DR: In this paper, the 3D quantum mechanical effect of the fringe field on the energy was extracted as a correction factor to the capacitance for each region, and the results were compared with those for a device with infinitely large gate.
Abstract: In this paper, we compare the 3D VQM expressions obtained for the capacitive energy of the oxide region and the depletion region with those for a device with infinitely large gate. The 3D quantum mechanical effect of the fringe field on the energy is then extracted as a correction factor to the capacitance for each region.
3 citations
01 Jul 2019
TL;DR: In this paper, the total charge density and single-stranded GDNA needed for the charge neutrality point (CNP) shift to take place was evaluated by simulating the GFET transfer characteristics using drift-diffusion model in MATLAB.
Abstract: Guanine nucleobases in DNA (GDNA) has a strong binding affinity towards lead (II) ions. Functionalized with graphene field-effect transistor (GFET), it makes an ideal sensing element for GFET-based sensor. The sensing is typically observed in the transfer characteristics of the GFET. Upon successful binding of GDNA with Pb2+, the Charge Neutrality Point (CNP) of the GFET will be right-shifted accordingly. This paper aims to evaluate the total charge density and single-stranded GDNA needed for the CNP shift to take place. This is achieved by simulating the GFET transfer characteristics using drift-diffusion model in MATLAB. The simulation takes into account graphene quantum capacitance, channel capacitance and related charges including the captured Pb2+ ions. It reproduces correctly the published transfer characteristics of GFET. Moreover, it also can estimate the CNP shift, number of single strand DNA needed, and number of ions captured. Knowing such features are essentials in enhancing the sensitivity and limit of detections of the GDNA-GFET sensor.
3 citations