Simulated annealing and first-principles study of substitutional Ga-doped graphene

The combination of Monte Carlo-based simulated annealing and ab initio calculations were applied to investigate the electronic and optical properties of substitutional Ga-doped graphene. During simulated annealing, it was observed the formation of gallium clusters, which may be an indication of the low dopant solubility. The obtained results indicate that the introduction of a single gallium atom in the graphene layer induces the formation of a band gap. Nevertheless, increasing the dopant concentration, the gap width fluctuates according to the number, odd or even, of dopant atoms. For an odd number, the gap width decreases with increasing dopant concentration. It was obtained that the structure distortions, produced by the introduction of the dopant atoms, induces significant changes in the electronic properties of the layer. Additionally, it is possible to infer that the optical absorption in the infrared region can be tuned as a function of the dopant concentration.