I tried to transfer monolayer WSe2 from sapphire substrates to PDMS, but I failed. The transfer process is very normal. First, coat WSe2 which is on sapphire with a thin film of PMMA by spin coating. Second, put the sample into BOE(buffer oxide enchant) to weaken the van der Waals force between WSe2 and sapphire. Third, peel the PMMA-WSe2 film and transfer it onto PDMS. Finally, remove PMMA by acetone. The first three steps are all no problem, but when the sample was dipped into acetone to remove PMMA, I found that the surface of PDMS was damaged, and also, WSe2 seemed to be damaged by the deformation of PDMS. Is there any other good method to transfer WSe2 from sapphire to PDMS, or is there any other solvent to remove PMMA? Thank you!
I am not sure I understand what you mean by the surface of PMMA was damaged in acetone. It should have dissolved in acetone, and unless the PMMA was cross-linked or overbaked, you shouldn't see much residue leftover. You can try hot-acetone (@65C on a hotplate), to see if that helps. The deformation of PDMS can damage your films, if they're large in size. What substrate is your PDMS on?
You could potentially add a few more steps if this continues to fail. Transfer the WSe2 film to a SiO2 substrate first, using the usual PMMA etch and clean method. Then, utilize a dry/stamp transfer method to just "pick up" the film with a PDMS stamp. Again, I suspect a large-area WSe2 film may buckle and crack due to PDMS deformation.
Dear Miss Liu, I have also tried to transfer 2D MoS2 or WS2 to other substrate or TEM Grid. When I immerse the PMMA/2D material into acetone to remove the PMMA layer. The PMMA will leave the target substrate and float on the surface of the acetone. May I know how do you remove the PMMA?
Hi, Baoshan. To remove PMMA, I usually immerse the PMMA/2D material/Substrate into acetone, as you said. But before doing this, I usually put the PMMA/2D material/Substrate into the oven (the temperature is 50 C) and leave it until the material to be completely dried and "pasted" on the substrate. And then immerse it into acetone. Hope it helps.
Dear Yanan, thanks for your help. I think the drying would be very necessary.
Wish both of us a good luck!
Hi everyone one,
I tried this method, but the PMMA coated on MoS2/sapphire sample was peeled off after 8 minutes putting it in BOE,
Can any help me
1. After coating PMMA on MoS2/sapphire sample for how much time we need to dip in BOE to weaken force between sapphire and MoS2.
2. How we can peel PMMA/MoS2 from PMMA/MoS2/sapphire, scotch tape ? or any other process
thanks
Hi All ,
I have graphene on a sapphire substrate grown by CVD method. I'm going to transfer graphene from a sapphire substrate to a TEM grid. What is a suitable method for transfer the monolayer on TEM grid?. I'm not interested in using any polymer residue or wet transfer approach.
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