Electronic and optical properties of passivated graphene nanomeshes: An ab initio study

Abstract

We propose new materials based on graphene nanomeshes (GNMs) and investigate the electronic and optical properties of them using a first-principles study based on density functional theory (DFT). We evaluate the electronic band structures, the projected density of states (PDOS), and optical spectra for semiconducting GNMs. We also study the passivation effect of various atoms on the electronic properties of GNMs and propose a new structure for passivating GNMs to improve their optical properties. The simulation results show that hydrogen (H) or fluorine (F) passivation of the edge sites of GNM holes results in an identical bandgap, whereas nitrogen (N) passivation causes these structures to transform from a semiconductor to a semi-metal. The absorption spectra show that the absorption of GNMs in high photon energies decreases with increasing hole size, while in low photon energies, the absorption of GNMs increases. Light absorption at low photon energies in new proposed GNM structures is two times that of other GNMs. So, the size, density of holes, and edge passivation are three significant factors that affect the properties of GNMs. These results show that GNMs may play a key role in nano-optoelectronic devices such as terahertz and infrared photodetectors (IR-PDs).