How can the electrical conductivity of graphene be measured?

In summary, there is limited information available on how the conductivity of graphene is measured, but it is likely that a similar method used for metal wires would be applied. Graphene does have a cross sectional area, and its conductivity can be measured by sandwiching it between layers and using a galvinometer. There is ongoing research on using graphene as a particle detector, but it requires clever techniques due to its thinness. Exposure to cosmic radiation may affect the conductivity of graphene, but it is a small and unlikely effect.
  • #1
Droctagonopus
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I've tried searching for it but while there are a lot of hits on the fact that graphene's conductivity is high, there seem to be very few on how the conductivity is actually measured.

Would you use the same method as you do with metal wires? Using cross sectional area, length, an ohmmeter and calculating the resistivity from that? Graphene doesn't have a cross sectional area, does it?

How would one go about measuring its conductivity?
 
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  • #2
Droctagonopus said:
I've tried searching for it but while there are a lot of hits on the fact that graphene's conductivity is high, there seem to be very few on how the conductivity is actually measured.

Would you use the same method as you do with metal wires?
Pretty much ... you have to adjust the exact details to the sample but the concept is much the same.

Using cross sectional area, length, an ohmmeter and calculating the resistivity from that? Graphene doesn't have a cross sectional area, does it?
Of course it does - atoms have a thickness too. You'll find resistivity data for different directions through a sample.

How would one go about measuring its conductivity?
Off the top of my head, I'd want to sandwich a sample between two layers of something else with a small hole for the electrical contact. So I'd be measuring the conductivity of three resistors in parallel, two of which I know.

I could also just use many layers of the stuff.

See:
http://www.nobelprize.org/nobel_prizes/physics/laureates/2010/advanced-physicsprize2010.pdf
 
  • #3
Thank you. :D

Another, kinda unrelated, question I want to ask. Would exposure to cosmic radiation, which is mainly fast moving protons affect the conductivity of a sample of graphene in any way?
 
  • #4
The technically correct answer is "no".
This is because "conductivity" is a material property.

But I suspect you are thinking something like, "if I bias a sample of graphene and put a galvinometer in the circuit - and a cosmic ray passes through the sample, would the galvinometer needle jump?"

i.e. could you use a sheet of graphene as a particle detector?

Short answer: probably.

Note: a proton stopped in the sheet will attract an electron - which slightly changes the current.
This is a really small effect, and considering how thin graphene sheets gets to be, an unlikely one.
To exploit graphene for particle detection you have to get clever.

Fox M. (2012) http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=6144014&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D6144014 IEEE Transactions in Nanotechnology May 2012

It's an area of active development.
 

1. How is electrical conductivity of graphene measured?

The electrical conductivity of graphene is typically measured using a four-point probe method, where four electrodes are placed on the surface of the graphene and a known current is passed through them. The voltage drop across the electrodes is then measured, and the conductivity can be calculated using Ohm's law. Other methods, such as scanning tunneling microscopy or Hall effect measurements, can also be used.

2. What factors affect the electrical conductivity of graphene?

The electrical conductivity of graphene can be affected by a variety of factors, including the number of layers of graphene, the presence of defects or impurities, and the type of substrate the graphene is placed on. Additionally, the doping level of the graphene, which can be controlled by introducing impurities or applying an external electric field, can also greatly influence its conductivity.

3. Can graphene's electrical conductivity be tuned?

Yes, the electrical conductivity of graphene can be tuned by changing its doping level. By introducing specific impurities or applying an external electric field, the number of free charge carriers in the graphene can be altered, thus changing its electrical conductivity. This ability to tune the conductivity makes graphene a promising material for various electronic applications.

4. How does graphene's electrical conductivity compare to other materials?

Graphene has one of the highest known electrical conductivities of any material, with values up to 100,000 times higher than copper. This is due to its unique electronic structure, which allows for extremely efficient transport of charge carriers. Additionally, graphene's conductivity is not affected by temperature, making it a potentially useful material for high-temperature applications.

5. Are there any challenges in measuring the electrical conductivity of graphene?

Yes, there are some challenges in accurately measuring the electrical conductivity of graphene. One major challenge is the small size of graphene, which can make it difficult to create electrodes and apply a current without disrupting the material. Additionally, the presence of defects or impurities can also affect the accuracy of measurements. However, with careful experimental design and advanced techniques, accurate measurements of graphene's electrical conductivity can be achieved.

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