Curving of graphene quantum dots by external electric field

Abstract

We investigated the curving of three different sizes of graphene quantum dots (GQDs), C24H12, C54H18, and C96H24, by vertical external electric fields from −0.035 to 0.035 atomic unit (a.u.) using density functional theory (DFT) with M06-2x functional and 6-31 g(d) basis set. The results demonstrated that GQDs can be curved with an external electric field (EEF). The curvature of GQDs varies with the field strength and size of GQDs. The curvature of GQDs is in the following order C96H24 > C54H18 > C24H12. The electronic structure (HOMO-LUMO gap) of GQDs is also affected by EEF. The bandgap becomes narrower when applied a stronger electric field. Therefore, the electronic property of GQDs can be tuned by EEF. We also found the HOMO-LUMO gap of GQDs to be varied with its curvature. Thus, an external electric field can induce the curvature of GQDs and can be used to modify its electronic structure.