You can use a four point probe set-up to measure the conductivity of your films. There are several companies who provide such systems. Alternatively if you can find a source-measure-unit which Keithley or Keysight provide as well, voyage meter and home-made four probe station, you build your own system.

The links below give you some ideas how to do it. Hope it helps.

https://en.napson.co.jp/technique/

http://four-point-probes.com/four-point-probe-manual/

dear Sara Bazhair ;

the best way to measure the conductivity of a surface coated with metal alloy is the four-point probe measuring device, Loresta Resistivity Meter, model MCP T400, from Mitsubishi, This meter measures the electrical resistance under 1.99 x 107 Ω. The electrical resistivity of the coated samples can be measured by contacting its surface with these four pins.

for more detailes can read the following reference;

https://www.pveducation.org/pvcdrom/characterisation/four-point-probe-resistivity-measurements

Dear Sara,

this is a very challenging task. This is due to the fact, that you must separate the conductivity of the supporting layer from the thin metallic surface layer. If you could make an isolating substrate with the same film (therefore you must produce intime 2 films on different substrates, then the 4 point methods - recommended by Xuhua and Mahmood- could be applied. I myself would more like Hall measurements.

In your case with 2 conducting layers optical methods must be recommended. The measurements of the reflectivity give a complex refractive index which is a function of the conductivity. I attach a Phd work which I found.

Regard

R. Mitdank

thank you this has been very useful !