Electronic and field emission properties of wrinkled graphene

Wrinkles can be seen as a kind of protrusion formed on the surface of graphene sheets. The response of the electronic properties of graphene wrinkles to charge injecting and external electric field, which is closely related to field emission properties, has been extensively studied by our first-principles calculations. We find that increasing the wrinkle size and its top curvature not only improves the field enhancement factor of the wrinkled graphene but also decreases the electron affinities and ionization potentials. When injecting charges, both the charge accumulation and depletion mostly distribute at the top parts of the wrinkles and become more concentrated in the wrinkle with a higher curvature. The change of the highest occupied molecular orbital and the lowest unoccupied molecular orbital caused by electric field mainly locates at the wrinkled parts, especially at its top. These results demonstrate that wrinkled graphene could be a good candidate for field emitter.