Dear colleague Mahdieh Zaji,
Have a nice time and good day,
Peace be up on you.
You can coat two electrodes on the film surface to use co-planner method or use sandwich method by coat on electrode first then deposit the wanted film on it the coat the second electrode.
Please see the two attached files, it may help you.
Yours
A. EL-Denglawey
Hi Mahdieh,
The best way to determine the (specific) resistivity of a polymer film (or thin film) is to use the transmission line method (TLM). You can find the details on the internet but it is a series of metal contacts on the polymer, either a variation in concentric rings or a series of dots in line, between which the resistance is measured. Plotting the resistance in a graph will give you the sheet resistance/specific resistance of the polymer (slope of the graph) and the contact resistance between polymer and metal (intercept on Y-axis). This is the method used to determine both these two important parameters. Be aware that using different metal contacts can lead to different contact resistances. They can be low ohmic or high ohmic (schottky). This depends on the work function of the metal, the fermi level of the polymer (assuming semiconductor behaviour), the electron affinity of the polymer and the doping level of the polymer. A general overview of this can be found in the link attached. I also attached a nice desciption of the TLM method.
https://en.wikipedia.org/wiki/Work_function
Dear Mahdieh Zaji! I would agree with Professor Eldenglawey.
And to check if you have got a good (ohmic) contact between metal electrodes and polymer film, you may measure I(U) dependence - it should be linear. Or you may measure R(U) - it should be constant.
Another possibility is to use an impedancemeter (after applying contacts to the film) and to analyze frequency dependencies of the film impedance. This way you will get more information on the film properties.
Another one possibility is to deposit your thin polymer film onto conducting substrate (lower electrode) and then to use the Scanning Spreading Resistance Microscopy (SSRM). This approach provides an information on the local resistance of the film and gives you a possibility to draw a map of the local resistance distribution over the film. This is extremely useful if you have a heterogeneous film.
Hi Mahdieh,
Besides the two-point measurement technique well explained by Professor Eldenglawey, there is also the four-point measurement technique. You can find more details about both these techniques in the attached file below.
Hi Mahdieh,
Please follow Dr. Peter Knapen's and Dr. Mohamed Akbi's comments. They are right. You can go for four probe measurement. At first do a metal contact my metallization on the film and then measure it with a standard source-measure unit. This will give you the resistance of the sample. Then you can find the resistivity or sheet resistance of the sample by doing simple mathematics. Moreover, the LTM method will give you the vivid results for specific resistance of the polymer film.
Best of work...
Sample resistance was measured by impedance spectroscopy at frequencies of 100 Hz ... 1 MHz.
The sum of ionic transference numbers was determined by the EMF method in the cell:
(Pt) │Ln2(WO4)3 │(Pt).
The effect of oxygen partial pressure on conductivity was measured
The nature of mass and charge transfer were determined by the Tubandt method in a two-piece cell:
(-)Pt│Ln2(WO4)3│Ln2(WO4)3│Pt(+)
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