Is it possible to spin coat a Silicon wafer with a suspension of graphene or graphene oxide to carry out XPS, AFM, and SEM characterisations?
Are there any protocols that show the ideal rpm value for efficient spin-coating?
Or else, use the drop-casting method instead of spin-coat?
Any suggestions of other wafers that I could use?
Thanks!
If your graphene or GO sample sticks with the Si wafer substrate nicely then I think it would be fine.
Spin coating at rpm 2000 and drying under IR irradiation for few times, sucessive drop casting and drying under IR irradiation are the two commonly used techniques for this purpose. However, I'll tell you to properly make sure that your GO sample sticks very nicely with the substrte because XPS is done under extremely high-vacuum level such as 2.2 x10-10 mbar.
Many thanks Ayan!
Just another small question: Why do you dry under IR radiation for a few times after spin coating?
Generally, you should dry whatever you have deposited on the substrate. It helps the deposited material to stick on the substrate and it also helps to evaporate the solvent you used for deposition. If you want to repeat the spin-coating or drop-casting process then you should dry the substrate in a clean and cool place every time, before you start the new spin-coating or drop-casting.
However, for FESEM sample preparation, I've seen people scattering their powder samples on he thin Al foil and then blowing the extra sample by a rubber air blower (available with JEOL FESEM).
Thank you very much for your informative answers.
My main concern is that if I leave the samples in a cool and clean place to dry, there would be still contamination from the atmosphere - especially for AFM and XPS. I thought of storing the samples, or leave them to dry in a clean desiccator under vacuum, but then the solvent would vapourise, and consequently would act as a contaminant.
You may do the drying process in an argon glove box to reduce the probability of contamination. If you have 'clean room' facility, you can use that also for sample preparation. However, clean laboratories with good air conditioning system are good enough for this type of sample preparation.
that's a good question and a good answer, I appreciate that and waiting for more discussions.
regards
Maytham
Maria Magro
The GO powder dispersed in DI water at a concentration of 5 mg/ml
to form a GO paste, which was spin-coated on the Si substrate at
3000 rpm in 50 s. (15 drop)
Dear Mohamed Refaey,
Thank you very much for your help! Much appreciated.
Regards
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