▎ 摘　　要

We measured the electric conductivity of large (25 x 50 mm) graphene films as a function of number of layers in the range of 1-20 layers. We also calculated the energy gap for such samples using density function theory. Our results showed a conductivity slightly above that of ITO for monolayer graphene and an exponential decrease as the number of graphene layers increased. Both experimental and simulation results showed a convergence of graphene into graphite at as little as 18-20 layers.