Hi Jia, TLM is the easiest one, but you will need let's say 5 structures and extrapolate Rc. The larger the number of structures, the better. Cross-Bridge Kelvin (CBK) can use just three contacts in total. The very minimum that you can do is ONE structure with only two contacts, in that case you will need to look the impedance vs frequency, as in parallel to Rc there always is a contact capacitance Cc. 

I uploaded for you this paper, sorry it's in French but the abstract is in English

https://www.researchgate.net/publication/257013565_Modle_de_propagation_large_bande_%28110_GHz%29_du_graphene

Let me know if you need more help on this.

P.S. Kamal, I'm very interested in your paper, could you upload the full text?

Conference Paper Modèle de propagation large bande (110 GHz) du graphene

Thanks Very Much, Vincenzi!

I don't comprehend that "Cross-Bridge Kelvin (CBK) can use just three contacts in total. The very minimum that you can do is ONE structure with only two contacts".

I read the abstract of your paper and I am curious that is GSG structure indispensable to extract the contact resistance by your method.

Thanks for your patience.

Hi Jia, no problem at all!

for the CBK structure you can have a look at this paper from Nagashio, on page 2 you'll see what I was referring to -->  http://link.aip.org/link/APPLAB/v97/i14/p143514/s1&Agg=doi

I'm sorry I can't give more info on that technique because I have limited internet access for now...

About the GSG structure, that is only necessary to study the impedance at very high frequencies (tens of GHz), but if you have a very basic device made of two electrodes and a patterned graphene strip you can measure it with an impedance meter up to a few hundreds of MHz. The impedance vs freq will give you a measure of Rc, Cc and Rsquare of your graphene device, so all the data on Rc that you'll need according to its very simple equivalent circuit. If you couple that measure with TLM for various graphene strip lengths you will be able to extrapolate the DC Rc value and double check the values you extracted before in frequency.

There are more papers on how to link the value of Rc to backgate bias (if you have a back electrode), its usefulness depends on what you're looking for.

I hope I helped, feel free to ask.

Best, Giancarlo