I got some info about the transferring method but not all the details, according to that process First, coat MoS2 which is on sapphire with a thin film of PMMA. Second, put the sample into BOE(buffer oxide etchant) to weaken the van der Waals force between MoS2 and sapphire. Third, peel the PMMA-MoS2 film and transfer it onto target sample. Finally, remove PMMA by acetone.
I tried this method but failed, the PMMA coated on MoS2/sapphire sample was peeled off after 8 minutes of putting it in BOE,
I want to know
1. For how much time we need to put PMMA/MoS2/sapphire in BOE to weaken the van der waals force between sapphire and MoS2.
2. How we can peel PMMA/MoS2 from PMMA/MoS2/sapphire, scotch tape ? or any other process
Anyone have experience and knowledge please help me
Hi Khalil,
I think you can dilute BOE in DI water to reduce the concentration and avoid that the PMMA will be etched away. For safety reasons I used KOH (2M) instead of BOE. In that case additional heating is necessary (~80oC) for 20-30 min. After that the the PMMA/MoS2 is barely attached to the surface and as soon as you transfer to DI water the surface tension will help to detach the film.
However, in some cases is not so easy to transfer, seems that it may be dependent of the quality of your film (residual oxide) may cause not homogeneous detach of the film (after you finish the transfer you may see some areas did not lift)
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