Abstract
The resistivity of ultraclean suspended graphene is strongly temperature (T) dependent for 5<T<240 K. At T-5 K transport is near-ballistic in a device of approximately 2 microm dimension and a mobility approximately 170,000 cm2/V s. At large carrier density, n>0.5 x 10(11) cm(-2), the resistivity increases with increasing T and is linear above 50 K, suggesting carrier scattering from acoustic phonons. At T=240 K the mobility is approximately 120,000 cm2/V s, higher than in any known semiconductor. At the charge neutral point we observe a nonuniversal conductivity that decreases with decreasing T, consistent with a density inhomogeneity <10(8) cm(-2).
Highlights
Graphene, a single layer of graphite, is a remarkable recent addition to the family of two-dimensional electronic materials
N > 0.5×1011cm−2, the resistivity increases with increasing T and is linear above 50 K, suggesting carrier scattering from acoustic phonons
The formation of electron and hole puddles can further contribute to scattering at low carrier density [12, 13]
Summary
A single layer of graphite, is a remarkable recent addition to the family of two-dimensional electronic materials. At T ∼ 5 K transport is near-ballistic in a device of ∼ 2 μm dimension and a mobility ∼ 170, 000 cm2/Vs. At large carrier density, n > 0.5×1011cm−2, the resistivity increases with increasing T and is linear above 50 K, suggesting carrier scattering from acoustic phonons. When the temperature is increased, the resistivity exhibits two distinct behaviors, depending on carrier density.
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