Gap Opening in Graphene via Locally Introduced Electric Field

Abstract

Utilizing first‐principle calculations, two systems of graphene/overlay are investigated. The overlays are made up of a self‐assembling molecular network (SAN) that introduces local electric fields in opposite directions on graphene. It is demonstrated that the patterned electric field via dipolar SAN, in addition to gating, can create a gap in graphene's band structure. Also, linearly dispersing bands of graphene are retained intact in a certain energy window in the vicinity of the Dirac point. Electronic gaps of 254 and 263 meV appear in the band structure of graphene. And the Fermi levels fall in the middle of the generated electronic gaps. The occurred shift through gating in the density of the state of graphene is detected by means of scanning tunneling microscope images, where the images distinguish the intact density of states from those affected by the dipolar overlay.