Tuning doping and strain in graphene by microwave-induced annealing

We propose microwave-induced annealing as a rapid, simple, and effective method of controlling surface doping and strain in graphene. Raman spectroscopy was used to confirm that heavy and uniform p-type (1.2 × 1013 cm−2) doping can be achieved within only 5 min without unintended defects by placing graphene onto a substrate with a sufficiently high dielectric constant and exposing graphene and its substrate to microwave irradiation. Further, we showed that ripples are formed in suspended graphene when it is exposed to microwave irradiation. Silicon has a sufficiently high dielectric constant (11.9) and graphene is commonly deposited on silicon-based substrates, so our proposed microwave-induced annealing technique can be used for the rapid manipulation of the properties of graphene at low cost.