I have a small quantity of Calcium Zinc Nitride material powder, Ca2ZnN2 and i want to make a film on a glass substrate using spin coating method. I've tried n-hexane as a solvent to disperse the material in it but i obtained a non homogeneous suspension, which gives a non proper film. The applied speed for spin coating was 1000 and 2000 rpm for one minute. I can try another spinning condition but the solution itself is not dispersed well. May I try a higher viscosity liquid.
Hello
I think in your case the problem comes from the solution as you have mentioned. In order to adjust the thickness, you need to check the viscosity (higher: thicker film, lower: thinner film). Also, check that you have a good solution texture (are you using an ultra-sonicator for the dispersion? Do you have bubbles or particles before performing the spin coating?)
Regards
Loraine
Dear Mostafa Shawky ,
Once a suspension is prepared from the particle as the n-hexane did NOT dissolve Ca2ZnN2 , a continuous film is not obtained. Spin coating may help to distribute the particle on the substrate but it does NOT help to join the particles with each other.
You may try:
- using heat treatment.
- deposit Ca2ZnN2 from its precursor.
I agreed with Imad Disher. It is quite tricky to dissolve inorganic materials into organic solvent if u donnt have any organic moleculars attached onto the surface of inorganic materials which we called ligand. But if u are able to make it small enough usually below 10 nm, it is possible to obtain a even suspension. In your case I think u should ultrasonicate the suspension for at least one hour and.then spin-coate it immediately for maybe 3 or 2 times.
Hello Mostafa,
Do you really need to follow the spin coating method to prepare the thin film?
If it's not necessary, you may have to try with the doctor blading method to make the film. In this method, you can control the thickness of the film as per your requirement. To go for the doctor blading method you may have to make the paste with the help of some solvent and surfactants.
If that is not working for your purpose, then you may have to try the other methods that Imad Disher suggested.
Hope this will help you.
Good Luck with your works!!!
Kulatheepan
Dear Mostafa,
your process is partially successful by careful and planned experimental work you can optimize your process. As the colleagues hinted the grain size in the powder is an effective parameter. As the grain size decreases the suspension becomes denser and more homogeneous. The other factor is the viscosity of the solvent. Then comes the speed of spinning. After each experiment you have to evaluate your film rigorously.
Wish you success.
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