The influence of vacancy defects on the electronic and phonon properties of graphene is studied with the models based on a unit cell of 180 carbon atoms and of 1, 2, 3, 6, and 24 vacancies. Ordered, with one defect per unit cell, and non-ordered (randomly arranged) vacancies are calculated with first-principle and molecular dynamics methods. Randomly oriented vacancies lead to a creation of characteristic V1(5-9) defects and the amorphization of graphene with different rings. Electronic and phonon densities of states are analyzed. The switching of the electrical conductivity from metal to semiconductor type is observed when increasing the defect sizes from a single vacancy to large clusters. The characteristic phonon modes are found in all these cases for their future experimental identification. Novel types of devices are proposed via doping of defective graphene.
- Electronic properties