I am trying to get suggestions on other ways I can calculate an accurate conductivity value without the use of a four-point probe. The thickness of the films are uniform (< 10µm variation) and the films are around 50 to 100µm thick, too thick for accurate measurements with the 4 pt probe set-up we have... I have been simply using a multi-meter as a two-point probe and calculating resistivity using Rho= R(A/L), resistance values of the films are between 10 kΩ and 10MΩ. Would something like a Hall Effect probe work for this case? My current set-up is pretty crude right now..
Thanks!
Dear Matthew,
If your resistance is in kohm and more, you can safely use two point probe. For more accurate measurements you have to make proper electrical contact using some conductive paste or depositing metallic film by evaporation technique. You can mount your film in a metallic sample holder and create vacuum inside to get rid of moisture and for electromagnetic shielding if the resistance is in megaohms.
If you are trying to measure ionic conductivity of the polymer film with two point probe? You can keep the sample between two stainless blocking electrodes and use the spring for good contact.See the attached figure for more information.
Our electrochemical work station could measure voltage-curtrent curves, whose slope is the resistance (R).
Thank you all. I was able to obtain sheet resistance values with the four point probe using silver paste to decrease the contact resistance, and making sure the current was in the correct range.
Could you clarify the range of current you used?
I'm using copper tape to reduce contact resistance. Should there be any major differences between different materials used? (ie. any difference between copper tape vs silver paste?)
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