Measurement of Scattering Rate and Minimum Conductivity in Graphene

Understand

The conductivity of graphene samples with various levels of disorder is investigated for a set of specimens with mobility in the range of $1-20\times10^3$ cm$^2$/V sec.

• Comparing the experimental data with the theoretical transport calculations based on charged impurity scattering, we estimate that the impurity concentration in the samples varies from $2-15\times 10^{11}$ cm$^{-2}$.
• In the low carrier density limit, the conductivity exhibits values in the range of $2-12e^2/h$, which can be related to the residual density induced by the inhomogeneous charge distribution in the samples.
• The shape of the conductivity curves indicates that high mobility samples contain some short range disorder whereas low mobility samples are dominated by long range scatterers.