Ask the Staff

ruchit.mehta.1 2012-03-29 08:28 PM
Electrical Measurements in solution
Hello!

I am trying to do electrical measurements on graphene FETs in solution medium. Going to perform the experiments in the Bio-wing.
However, I am not completely sure how to proceed with it. I have large area graphene which is contacted through silver paint. How do I go about passivating these contacts before exposing the sample to the solution. Also, what kind of instruments are available in Birck for these kind of liquid medium measurements? Just want to know the best strategy forward.

Any kind of help would be appreciated !
Thank you.

-
Ruchit

aamer.mahmood.1 2012-03-30 01:33 PM
Electrical measurements in a solution
Ruchit,
Based on our discussion, I understand that you have small (10s of micrometer range) graphene channels and aluminum pads to serve as electrical contact pads at the ends of the channels. You want to make VI measurements across the graphene channels.
Before measurements in saline solution, you need to have the right kind of package and this reply deals with that.
Given the small size of your samples, I suggest you mount your samples on slightly larger substrates like FR4. Get untrasonic wire bonds from the device Al to the larger Cu pads on the FR4 and use conductive epoxy to connect test wires to the larger Cu pads. You can cover the larger Cu as well as the smaller Al pads with dielectric epoxy for passivation. This should provide you with a mechanically and electrically strong and robust connection.
Please discuss with Gale Lockwood before proceeding as she has a lot of experience with similar bonding and packaging jobs.
Best regards.
-Aamer Mahmood