How do I measure the mobility and conductivity of graphene? And another question, if I know the conductivity of graphene,how to calculate the conductance of the graphene flake theoretically since the conductance and conductivity of graphene have the same unit of [1/ohm].
Thank you, Hai-Yao.
As I understand, for a rectangular shaped graphene,conductane=W/L*conductivity.
Another question is how to measure the conductivity of graphene. I know I can calculate the mobility of graphene according to the relation:sigma=mu*e*n.
Best
Happy Mid-Autumn Festival.
Fuwei Qiu
The Van der Pauw method can be used to measure the resistivity, and hence conductivity, of graphene. You can find a description of the van der Pauw method in most text books on semiconductor characterization. You are correct that the mobility can be calculated from the conductivity, but the carrier density must be known. If this is not known, the carrier density can be measured using the Hall effect..
Thank you Jeffrey,
As the thickness of graphene is so small, the arrange of the electrode is rather difficult.So I think we can't measure the conductivity of graphene in the same way as semiconductor.
You are right ,we can mearsure the carrier density of graphene using the Hall effect.But for graphene, we can get the knowledge of carrier density if we know the thickness and biasing voltage of substrate,as is the described by Novoselov in [Two-dimensional gas of massless Dirac fermions in graphene]
Thank you for you consideration
Fuwei Qiu
2014,09,18
I think the four-point-probe measurement and van der pauw will be harmful to apply to the sensitive graphene layer. Non-contact sheet resistance measurement using high frequency eddy current will work better from my experience. https://en.wikipedia.org/wiki/Sheet_resistance#measurement
The graphene layer should be on a non-conductive substrate, otherwise the substrate will highly affect the measurement.
Please How can we proceed to measure the conductivity and mobility of the sheet of graphene when this sheet is too thin and so fragile ?Can we used Eddy current methods .Thank you very much
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