Hi,
I am wanting to do some Hall mobility measurements on graphene-based thin films (continuous, cm-scale). Does anyone have any advice on how best to do this? Any technical advice, good commercial systems you would recommend, example references you'd like to share, etc.?
Thanks in advance!
Dear friend Zacary L. Croft
Hall mobility measurements are commonly used to study the electronic properties of thin films, including graphene-based films. To perform Hall measurements on thin films, a magnetic field is applied perpendicular to the film surface, and the transverse voltage is measured as a function of the current passing through the film. This allows for the determination of the carrier density, Hall coefficient, and mobility of the material.
There are various methods and instruments available for Hall mobility measurements on thin films, including van der Pauw and Hall bar techniques. The choice of method and instrument depends on the specific requirements of the experiment, such as the size and shape of the sample, the temperature range, and the desired accuracy and sensitivity of the measurement.
Some commercial systems that can be used for Hall mobility measurements on thin films include the Lakeshore 8400 Series Hall Effect Measurement System and the Ecopia HMS-5000 Hall Measurement System. However, there are many other options available on the market.
Some example references related to Hall mobility measurements on graphene-based thin films include:
1. Novoselov, K. S., et al. "Two-dimensional gas of massless Dirac fermions in graphene." Nature, vol. 438, no. 7065, 2005, pp. 197-200.
2. Tan, Y. W., et al. "Measurement of scattering rate and minimum conductivity in graphene." Physical Review Letters, vol. 99, no. 24, 2007, p. 246803.
3. Wang, W., et al. "Improved Hall mobility of epitaxial graphene grown on 6H-SiC (0001) substrate by high-temperature annealing." Applied Physics Letters, vol. 92, no. 20, 2008, p. 203102.
4. Liu, L., et al. "High mobility ambipolar graphene field effect transistor using epitaxial graphene on SiC substrate." Applied Physics Letters, vol. 94, no. 17, 2009, p. 173104.
These references provide some examples of the use of Hall mobility measurements in graphene research and may serve as a starting point for further literature searches.
Deposit Au 1 micron thickness to make the Hall contacts on graphene. Distance between current contacts is 1 - 1.5 cm. Distance between Hall voltage contacts is 5 mm.
With a current of 1 mA between the Hall current contacts you could measure 1 mV (say) Hall voltage using 0.1 T magnetic field for a good semiconductor.
If you do not use Au contacts deposited on graphene use Silver paste (as a drop) to make the current and voltage Hall contacts.
https://www.nist.gov/image/bighallbar970png
Dear sir, how to know wether my material is p-type or n-type from the meaurement data.
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