TY - JOUR
T1 - Simulation of Bipolar Charge Transport in Graphene by Using a Discontinuous Galerkin Method
AU - Armando Majorana,  Giovanni Nastasi & Vittorio Romano
JO - Communications in Computational Physics
VL - 1
SP - 114
EP - 134
PY - 2019
DA - 2019/02
SN - 26
DO - http://doi.org/10.4208/cicp.OA-2018-0052
UR - https://global-sci.org/intro/article_detail/cicp/13028.html
KW - Graphene, bipolar charge transport, discontinuous Galerkin method.
AB - <p style="text-align: justify;">Charge transport in suspended monolayer graphene is simulated by a numerical deterministic approach, based on a discontinuous Galerkin (DG) method, for
solving the semiclassical Boltzmann equation for electrons. Both the conduction and
valence bands are included and the interband scatterings are taken into account.<br/>The use of a Direct Simulation Monte Carlo (DSMC) approach, which properly
describes the interband scatterings, is computationally very expensive because the valence band is very populated and a huge number of particles are needed. Also the choice
of simulating holes instead of electrons does not overcome the problem because there
is a certain degree of ambiguity in the generation and recombination terms of electron-hole pairs. Often, direct solutions of the Boltzmann equations with a DSMC neglect
the interband scatterings on the basis of physical arguments. The DG approach does
not suffer from the previous drawbacks and requires a reasonable computing effort.<br/>In the present paper the importance of the interband scatterings is accurately evaluated for several values of the Fermi energy, addressing the issue related to the validity
of neglecting the generation-recombination terms. It is found out that the inclusion of
the interband scatterings produces huge variations in the average values, as the current, with zero Fermi energy while, as expected, the effect of the interband scattering
becomes negligible by increasing the absolute value of the Fermi energy.</p>