Quantum capacitance

About: Quantum capacitance is a research topic. Over the lifetime, 954 publications have been published within this topic receiving 24165 citations.

Side-gate modulation effects on high-quality BN-Graphene-BN nanoribbon capacitors

Abstract: High-quality BN-Graphene-BN nanoribbon capacitors with double side-gates of graphene have been experimentally realized. The double side-gates can effectively modulate the electronic properties of graphene nanoribbon capacitors. By applying anti-symmetric side-gate voltages, we observed significant upward shifting and flattening of the V-shaped capacitance curve near the charge neutrality point. Symmetric side-gate voltages, however, only resulted in tilted upward shifting along the opposite direction of applied gate voltages. These modulation effects followed the behavior of graphene nanoribbons predicted theoretically for metallic side-gate modulation. The negative quantum capacitance phenomenon predicted by numerical simulations for graphene nanoribbons modulated by graphene side-gates was not observed, possibly due to the weakened interactions between the graphene nanoribbon and side-gate electrodes caused by the Ga+ beam etching process.

Simulation and analysis of quantum capacitance in single-gate MOSFET, double-gate MOSFET and CNTFET devices for nanometre regime

Abstract: Carbon nanotube based FET devices are getting more and more importance today because of their high channel mobility and improved gate capacitance versus voltage characteristics In this paper we compare and analyse the effect of gate capacitance on varying oxide thickness for single gate MOSFET, double gate MOSFET and CNTFET It is seen that in nanometre regime quantum capacitance plays the major role in deciding the gate capacitance of a CNTFET and we find a favourable characteristics of decreasing gate capacitance with the decrease in the oxide thickness which is not possible to get in single gate silicon MOSFET and double gate MOSFET

rf Quantum Capacitance of the Topological Insulator Bi 2 Se 3 in the Bulk Depleted Regime for Field-Effect Transistors

Abstract: A metal-dielectric topological-insulator capacitor device based on hexagonal-boron-nitrate-(h-BN) encapsulated CVD-grown Bi 2 Se 3 is realized and investigated in the radio-frequency regime. The rf quantum capacitance and device resistance are extracted for frequencies as high as 10 GHz and studied as a function of the applied gate voltage. The superior quality h-BN gate dielectric combined with the optimized transport characteristics of CVD-grown Bi 2 Se 3 (n ∼ 10 18 cm −3 in 8 nm) on h-BN allow us to attain a bulk depleted regime by dielectric gating. A quantum-capacitance minimum and a linear variation of the capacitance with the chemical potential are observed revealing a Dirac regime. The topological surface state in proximity to the gate is seen to reach charge neutrality, but the bottom surface state remains charged and capacitively coupled to the top via the insulating bulk. Our work paves the way toward implementation of topological materials in rf devices.

Scaling effects on the gate capacitance of graphene nanoribbon transistors

Abstract: Scaling effects on the gate capacitance of graphene nanoribbon field-effect transistors (GNRFETs) are studied by means of a semi-analytical model. The influence of nanoribbon width, gateinsulator thickness and dielectric constant scaling on the capacitance — voltage characteristics is explored. Gate capacitance has non-monotonic behavior with ripples for thin and high-k gate-insulators. However, beyond the quantum capacitance limit, the ripples are suppressed and smooth monotonic characteristics are obtained.