Electron mobility calculation for graphene on substrates

Abstract

By a semiclassical Monte Carlo method, the electron mobility in graphene is calculated for three different substrates: SiO2, HfO2, and hexagonal boron nitride (h-BN). The calculations account for polar and non-polar surface optical phonon (OP) scatterings induced by the substrates and charged impurity (CI) scattering, in addition to intrinsic phonon scattering in pristine graphene. It is found that HfO2 is unsuitable as a substrate, because the surface OP scattering of the substrate significantly degrades the electron mobility. The mobility on the SiO2 and h-BN substrates decreases due to CI scattering. However, the mobility on the h-BN substrate exhibits a high electron mobility of 170 000 cm2/(V·s) for electron densities less than 1012 cm−2. Therefore, h-BN should be an appealing substrate for graphene devices, as confirmed experimentally.