Technologies are generally described for a method and system configured effective to alter a defect area in a layer on a substrate including graphene. An example method may include receiving and heating the layer to produce a heated layer and exposing the heated layer to a first gas to produce a first exposed layer, where the first gas may include an amine. The method may further include exposing the first exposed layer to a first inert gas to produce a second exposed layer and exposing the second exposed layer to a second gas to produce a third exposed layer where the second gas may include an alane or a borane. Exposure of the second exposed layer to the second gas may at least partially alter the defect area.