Determining Graphene and Substrate Quality from the Coupled Hall Mobility Measurements and Theoretical Modeling

An increase of mobility up to ~2600 cm
²
/Vs is observed in graphene by Hall bar characterization within the temperature range from 40 K to 300 K. The increasing trend is attributed to Coulomb scattering by employing theoretical modeling based on the momentum relaxation time approximation of the Boltzmann transport equation. We also find that at room temperature and for higher charge densities additional mechanisms such as lattice defect and/or substrate corrugation scattering become important and restrict the mobility down to only ~200 cm
²
/Vs and carrier mean free paths well under ~35nm.