Effect of proton irradiation on graphene layers

HRTEM analysis has been performed on proton irradiated graphene. The analysis indicates the existence of Moire patterns produced by the rotations induced by the irradiation between planes. The rotations measured fluctuate between 3° and 5°, respectively. These rotations may influence the electronic properties of the material under investigation. To explain the observed rotations between planes, theoretical analysis were performed under the scheme of extended Huckel tight-binding method. Average total energy of the system was monitored throughout the experiment composed of two graphene layers with two carbon vacancies and then intercalated in between the two layers. The results obtained indicate that the system remain semi-metallic. Moreover, the theoretical results yielded that the 3-degree rotation is favored, although the 5-degree rotation is not discarded. Furthermore, energy bands as well as total and projected DOS were performed in order to provide more information about the electronic changes induced by the rotations applied to the system.