Showing papers by "Vittorio Romano published in 2014"
TL;DR: In this paper, a hydrodynamical model for simulating charge transport in graphene is formulated by using of the maximum entropy principle and both electrons in the conduction band and holes in the valence band are considered and it is assumed a linear dispersion relation for the energy bands around the equivalent Dirac points.
Abstract: A hydrodynamical model for simulating charge transport in graphene is formulated by using of the maximum entropy principle. Both electrons in the conduction band and holes in the valence band are considered and it is assumed a linear dispersion relation for the energy bands around the equivalent Dirac points. The closure relations do not contain any fitting parameters except the ones already present in the kinetic description.
47 citations
TL;DR: In this paper, the authors present a macroscopical model for charge transport in compound semiconductors to make use of analytic ellipsoidal approximations for the energy dispersion relationships in the neighbours of the lowest minima of the conduction bands.
Abstract: We present the first macroscopical model for charge transport in compound semiconductors to make use of analytic ellipsoidal approximations for the energy dispersion relationships in the neighbours of the lowest minima of the conduction bands. The model considers the main scattering mechanisms charges undergo in polar semiconductors, that is the acoustic, polar optical, intervalley non-polar optical phonon interactions and the ionized impurity scattering. Simulations are shown for the cases of bulk 4H and 6H-SiC.
14 citations
03 Jun 2014
TL;DR: In this article, a hydrodynamical model for the charge and the heat transport in graphene is presented, where macroscopic variables are moments of the electron, hole and phonon distribution functions, and their evolution equations are derived from the Boltzmann equations by integration.
Abstract: In this paper we present a hydrodynamical model for the charge and the heat transport in graphene. The macroscopic variables are moments of the electron, hole and phonon distribution functions, and their evolution equations are derived from the Boltzmann equations by integration. The system of equations is closed by means of the maximum entropy principle and all the main scattering mechanisms are taken into account. Numerical simulations are presented in the case of a suspended graphene monolayer.
10 citations
TL;DR: Cheng et al. as mentioned in this paper used a numerical scheme based on the discontinuous Galerkin method for finding deterministic (non stochastic) solutions of the electron Boltzmann transport equation in graphene.
Abstract: The aim of this work is to use a numerical scheme based on the discontinuous Galerkin method for finding deterministic (non stochastic) solutions of the electron Boltzmann transport equation in graphene. The same methods has been already successfully applied to a more conventional semiconductor material like Si (Cheng et al., Comput Methods Appl Mech Eng 198(37–40):3130–3150, 2009; Cheng et al., Boletin de la Sociedad Espanola de Matematica Aplicada 54:47–64, 2011). A n-type doping or equivalently a high value of the Fermi potential is considered. Therefore we neglect the inter band scatterings but retain all the main electron-phonon scatterings. Simulations in graphene nano-ribbons are presented and discussed.
1 citations
TL;DR: In this paper, a hydrodynamical model for the charge and the heat transport in graphene is presented, where state variables are moments of the electron, hole and phonon distribution functions, and their evolution equations are derived from the respective Boltzmann equations by integration.
Abstract: A hydrodynamical model for the charge and the heat transport in graphene is presented. The state variables are moments of the electron, hole and phonon distribution functions, and their evolution equations are derived from the respective Boltzmann equations by integration. The closure of the system is obtained by means of the maximum entropy principle and all the main scattering mechanisms are taken into account. Numerical simulations are presented in the case of a suspended graphene monolayer.
01 Jan 2014
TL;DR: In this article, a double-gate MOSFET was simulated by using a subband model based on the maximum entropy principle (MEP), and the model was shown to work well on a nanoscale double-gated MOSFLET.
Abstract: A nanoscale double-gate MOSFET is simulated by using a subband model based on the maximum entropy principle (MEP).
TL;DR: In this article, an optimal control approach based on the adjoint method for the design of a semiconductor device is considered, and a consistent energy transport model, free of any fitting parameters, formulated on the basis of the maximum entropy principle (MEP) is used as mathematical model.
Abstract: An optimal control approach based on the adjoint method for the design of a semiconductor device is considered. A consistent energy transport model, free of any fitting parameters, formulated on the basis of the maximum entropy principle (MEP) is used as mathematical model. The robustness of the optimal control approach is verified by a numerical sensitivity analysis, performed by introducing a Gaussian noise in the reference doping profile.