Here's a problem that I thought was solved, but this article was published less than a month ago. Graphene has no band gap. Transistors don't switch off.

LOL

http://www.technologyreview.com/view/518426/how-to-save-the-troubled-graphene-transistor/

It's interesting that this fact never came up in the IBM article.

There are many articles that suggest possible workarounds, but these are largely in the theoritical realm, with no practical examples to send around with engineers.