ABSTRACT We measured the electric conductivity of large (25 × 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.

中文翻译：

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石墨烯到石墨；电导率的逐层实验测量和密度函数理论计算

摘要 我们测量了大（25 × 50 毫米）石墨烯薄膜的电导率作为 1-20 层范围内层数的函数。我们还使用密度函数理论计算了此类样品的能隙。我们的结果显示单层石墨烯的电导率略高于 ITO，并且随着石墨烯层数的增加呈指数下降。实验和模拟结果都显示石墨烯在 18-20 层处会聚成石墨。