This is no efficient method to remove PR residue on graphene. In my opinion, UV ozone treatment may remove PR residue partly but the treatment time should been controlled. Overtreatment by UV ozone will introduce defects in graphene. After all the best way is insert a isolating layer between graphene and PR. 

Depends on your type of PR... cleaning with acetone or NMP followed by thermal annealing in Ar/H2 may help

DMSO is a great photoresist stripper for Novolac & epoxy based resists especially if you heat it to about 150oC. 

Dear Ron Reiserer,

I am curious that is graphene be destroyed by DMSO at 150℃?

And is there any matters need attention in DMSO clean process?

Thank you!

Stripper such as NMP may not suit for PR removing for graphene patterning since that always peel off graphene from substrate. And thermal annealing did little help to PR removing. I think adding a isolating layer between graphene and PR was the best way, just as Kunpeng Jia said.

Kunpeng Jia ,

what kind isolating layers be used to seperate PR and graphene?

A water soluble barrier layer like PVA could be compatible with a large array of substrates.

Since graphene can be stable to ~2600K (Kim et al. Phys. Status Solidi RRl 4, 2010), I don't believe that high temperature processes will damage it's structure. There is, of course, the matter of edge chemistry that is most definitely temperature sensitive.

There is also the matter of adhesion, thermal and chemical stability of the suspending substrate. You won't want to use temperatures that cause the substrate to decompose, and even the CTE of the material may cause adhesion failures if it is vastly different than the graphene.

As far as the DMSO goes, it has been successfully used in exfoliation of graphene in liquid phase and one group reported that it as among the top in stabilizing liquid suspensions (sorry I don't have the ref... someone at MIT I think) as far as aggregation goes. DMSO is also used in many graphene protocols, so I think it is a safe solvent for the graphene. The substrate may be a different story.

DMSO is frequently used in cleanroom processes but you should always check with the cleanroom manager to see if they allow it. Sometimes it may be allowed in some areas and not others.

Dawuth Pathan

Aluminum oxide is commonly used as isolating layer between graphene and PR.

How to remove aluminum oxide before PR patterning? Is there any side effect for introducing this isolation layer? Compared to UV/ozone treatment, which one you recommended for large area manufacture integration process? thank you.