Showing papers by "Vittorio Romano published in 2016"

Monte Carlo Analysis of Thermal Effects in Monolayer Graphene

Abstract: Thermal effects in monolayer graphene under an electron flow are investigated with a Monte Carlo (MC) analysis. The crystal heating is described by simulating the phonon dynamics. In particular, the balance equations for the energy of acoustic, Γ optical, and K phonons are deduced. They contain a heating source which is evaluated by counting the emission and absorption processes during the MC simulation of electron flow. The rate of temperature rise is obtained for several Fermi energies and applied electric voltages.

Charge transport and mobility in monolayer graphene

Abstract: For electron devices that make use of innovative materials, a basic step in the development of models and simulation computer aided design (CAD) tools is the determination of the mobility curves for the charge carriers. These can be obtained from experimental data or by directly solving the electron semiclassical Boltzmann equation. Usually the numerical solutions of the transport equation are obtained by Direct Simulation Monte Carlo (DSMC) approaches with the unavoidable stochastic noise due to the statistical fluctuations. Here we derive the mobility curves numerically solving the electron semiclassical Boltzmann equation with a deterministic method based on a discontinuous Galerkin (DG) scheme in the case of monolayer graphene. Comparisons with analytical mobility formulas are presented.

Erratum to: Building bridges for innovation in ageing: Synergies between action groups of the EIP on AHA

Abstract: The authors would like to change and use the correct name of M. Khaitov which is M. Kaitov on this manuscript. The authors have incorrectly used her other name during the finalization of this research. With this, the authors hereby publish the correct author names as presented above.

Electron Quantum Transport in Disordered Graphene

Abstract: We discuss the strategies for the calculation of quantum transport in disordered graphene systems from the quasi-one-dimensional to the two-dimensional limit. To this end, we employ real- and momentum-space versions of the non-equilibrium Green’s function formalism along with acceleration algorithms that can overcome computational limitations when dealing with two-terminal devices of dimensions that range from the nano- to the micro-scale. We apply this formalism for the case of rectangular graphene samples with a finite concentration of single-vacancy defects and discuss the resulting localization regimes.

Deterministic solutions of the Boltzmann equation for charge transport in graphene on substrates

Abstract: In this paper, the low and high field mobilities of graphene on substrates are studied, by means of deterministic solutions, obtained using a Discontinuous Galerkin (DG) numerical scheme, of the semiclassical Boltzmann equation for charge transport in graphene. It is shown that there is a strong dependence on the distance between the impurities and the graphene layer with significant changes both in the low and high field mobility curves. We remark that the use of a DG scheme avoids the intrinsic noise typical of the Direct Monte Carlo Simulation (DSMC) results and allows to evaluate the low field mobility with considerable accuracy, making less ambiguous the comparison with experimental measurements.