I am using PG remover for lift-off purpose. I heat metal deposited sample in PG remover at 70C for carrying out lift-off process faster. Does is affect electronic properties of graphene?
Remover PG is NMP-based solvent mixture. So, residual NMP molecules might affect the electrical properties of graphene such as Dirac point because lone pair electrons in pyrollidone functional group of NMP can be donated to the graphene, resulting in n-doping. However, NMP is a small molecule and can be removed by the conventional baking process. I would suggest that you carry out the high temperature annealing of your device after lift-off process to remove residual NMP completely. Because the boiling temperature of NMP is relative high (~210C), annealing around 200C would be recommended. This high temperature annealing is also helpful to remove the residual water molecules that induce p-doping of graphene.
In our lab, we remove LOR resist with xylene at 80°C, and graphene quality is OK
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