Room temperature velocity saturation in intrinsic graphene

We report ensemble Monte Carlo (EMC) studies of velocity saturation in intrinsic graphene at room temperature. The parameters for the phonon scatterings were obtained from fitting experimental data of graphene sheets in a variety of dielectric media, in which mobilities as high as 44,000 cm ²/Vs were observed at 300 K. In our work, velocity saturation was clearly observed at low carrier density (≤5×10¹² cm ^-2). Saturation velocity as high as 5.4×10⁷ cm/s was achieved at the lowest density (5×10¹¹ cm^-2). Only scatterings due to the acoustic phonon and the K-point intervalley optical phonon were considered in the simulation. As the density increases, the onset value increases and the saturation velocity decreases.