Hello Jose,

What film thickness were you looking for? I imagine the viscosity of the SU-8 will strongly affect the CNT dispersion.

I currently use cyclopentanone to dilute SU-8 and have managed to achieve SU-8 films down to 80 nm.

How are you currently mixing the SU-8 and CNTs? Could you try sonicating the solution?

What spin settings (ramp/speed/duration) are you using? Again, I imagine that the spin speed/duration may affect the dispersion of CNTs through the SU-8.

I guess mixing CNT is a good option to increase the conductivity of SU-8 film. I think you should revisit the mixing method to improve the dispersion of CNT. Good dispersion of CNT into SU-8 matrix will provide  good conductivity to the film.

Also, just a thought, you could try  Polyaniline in place of CNT as an alternative. Impregnation by metal nano-particle into the SU-8 matrix may helps too.

Best wishes!

Kunal

@ Jules

Thanks for your reply.

I am looking for thickness in the range of 2 to 5 um. Yeah..I accept that the viscosity of SU-8 will increase as we mix CNT with it. We are mixing in such a way that we could spin coat the solution over silicon wafer for the desired thickness. But in almost all the trials, after doing lithography, the CNTs look aggregated at some point instead of well dispersed throughout the film. I tried 1-Methoxy-2-propanol acetate as a solvent, but the results were not good. We did both probe sonication and ultrasonication. I will use cylopentanone as a solvent and check the dispersion quality.

Thanking you again.

@kunal,

Thanks for the reply,

I am planning to redo the experiment with different solvents. Also I have plans to use PANI to improve conductivity of SU-8.