Currently, graphene has to be removed from its growth substrate to an insulating surface for most applications. This transfer requires the introduction of polymer supports, which inevitably contaminate the graphene surface. Ideas to effectively remove these polymer contaminants are encouraged.
Ar/H2 annealing for long hours always helps. If you want to carry out low temp measurements in a cryostat then the best way to go is to do also a current annealing to your device. There are some papers out there that claim cleaner transfer techniques; are you happy with the one that you currently use?
If you already at some device level. I would recommend to get a high current through it under a vacuum. All fragments (small one, non-covalent contaminants) will go away (Transforming amorphous carbon into graphene by current-induced annealing arxiv (submitted 2012) ). In case, If you have lots of long chains and an amorphous carbon there, I would better use an electron beam exposition (graphene crossection for electrons is smaller than in case dust, so dust will be crashed and evaporated this way). Here is some paper on this issue too: Amorphous Carbon under 80 kV Electron Irradiation: A Means to Make or Break Graphene Adv. Mat. 2012. It is not an extremely cheap way, e-beam I mean, but it is a way.
@Avdoshenko... annealing in vaccum under high voltage looks interesting.. I have a doubt, did you observe any heat buildup in the devices at high voltages?..
will be waiting for your paper in arxiv.. :)
"heat buildup" i'm not quite sure what you mean. But the paper is already on arxiv, you can check your guess/doubts. :) http://arxiv.org/abs/1201.3131
Thanks for that link.. so technically its joule heating that induce graphene healing..
That's right, but if the thing on top is small enough it would be evaporated essentially.
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