▎ 摘　　要

Doping is usually considered as a common approach for improving properties of substances. Theoretical studies on graphene show that doping can effectively change the electrical properties of graphene, and it causes the graphene to behave like a metal or a semiconductor. In the present study, doping of the fourth group elements of the periodic table, including silicon, germanium, and tin in the graphene lattice has been computationally studied. To this end, a mix of quantum and simulation calculations has been used. Since elements of the fourth group have four valence electrons similar to carbon, it is expected that doping of these elements does not change bond hybridization. However, graphene is converted from a smooth state to a pyramid wrinkled state on the doped site for reducing van der Waals repulsion because of the difference in size of the doped atoms with carbon. In fact, the amount of wrinkles or, in the other words, height of the created pyramid depends on the size of the doped atom, and this can improve the hydrophobicity of graphene. In this work, we developed a theoretical model to investigate the effect of doping on hydrophobicity. We also performed molecular dynamics simulations on copper coated by graphene and Si-doped graphene. The results of our simulation are very close to the results of the theoretical model and show that doping increases graphene hydrophobicity.