Researchers from Cornell University have shown that in bilayer graphene, defects can influence the conductivity. In fact, the bilayer graphene, when it is stacked and staggered, has ripples (called solitons) which act like electrical highways. The rest of the non-rippled bi-layer graphene is semiconducting.
Up until now it was predicted that bilayer graphene is uniformly semiconducting when stacked and staggered. The researchers say that ideally they'd like to get rid of those solitrons, or control their formation - to have one "electrical highway" but not so many. So controlling bilayer graphene solitrons may enable controlling graphene's electrical properties.
Two different research groups in Cornell published articles on that - one from the experiment side and one describing the theory and mathematics behind the electrical properties of the solitons.