Ab Initio Study of Mono-Layer Graphene as an Electronical or Optical Sensor for Detecting B, N, O and F Atoms M. GOUDARZI, 1 S.S. PARHIZGAR, 1,3 and J. BEHESHTIAN 2 1.—Plasma Physics Center, Science and Research Branch, Islamic Azad University, Tehran, Iran. 2.—Chemistry Department, Faculty of Sciences, Shahid Rajaee Teacher Training University, Tehran, Iran. 3.—e-mail: ssparhizgar@gmail.com Using a first-principles calculation, the electronic and optical properties of graphene with B, N, O and F atom adsorption was studied. For the adatoms studied, distortion of the graphene layer is significant and causes a change in hybridization from sp 2 to sp 3 . Also, it was found that B atom adsorption on graphene is n-type, F and O atoms adsorption on graphene are p-type semi- conductor, while N adsorption has a metal behavior. N-absorbed graphene shows a magnetic moment, while B-, O-, and F-absorbed graphene show no magnetic moment. The optical absorption spectra of monolayer graphene have been calculated for the cases of in-plane (E^c), out of plane (E||c) and 45° polarization of light to the plane of the graphene layer and have been com- pared with atom adsorption on graphene. For (E^c), it was observed that the graphene was an optical sensor for finding F gas. In (E||c), it is an optical sensor for detecting the B atom in the environment. Key words: Graphene, density functional theory (DFT), structural and optical properties, absorption coefficient INTRODUCTION Graphene, a single layer of graphite formed by a repetitive hexagonal lattice with sp 2 hybridization, was successfully obtained in 2004. 1 After successful synthesis of graphene and the experimental obser- vation of Dirac fermions in graphene, great atten- tion was paid by the scientific community to the unique structural, mechanical and electronic prop- erties of this new material and other derivatives such as graphene oxide, and its potential use as a new technology. 2–4 This novel discovery is a promis- ing candidate for various technical applications such as spintronic devices, gas sensors, light-emit- ting diodes, photovoltaics and ultracapacitors. 5–8 Since the performance of graphene-based devices generally depends on the electronic, magnetic and optical properties of graphene, many experimental and theoretical studies have been conducted to investigate and change the properties of graphene to improve its chemical and physical properties for better uses. 9,10 One way to change the properties of graphene is to absorb various atoms on the graphene layer. In this regard, many theoretical studies have been carried out with most of them focused on the stable configuration of metal adatoms on gra- phene, 11 mixed hybridization in inducing mag- netism 12,13 and charge transfer between adatoms and graphene. 14 Using a first-principles calculation, Duplock et al. 15 showed that the adsorption of a hydrogen atom on graphene opened a band gap in the electronic density of states (DOS) in which a spin-polarized gap state appeared. Zhang et al. 16 discovered that Ca-, Co- and Fe-doped nanolayers and graphene with a vacancy nanolayer show much higher affinities to H 2 S molecules in comparison to pure graphene. In other spin-polarized ab initio calculations, it was found that the carbon adatoms on a graphene layer make a magnetic moment of about 0.5 l B . 17 (Received October 25, 2018; accepted April 3, 2019; published online April 12, 2019) Journal of ELECTRONIC MATERIALS, Vol. 48, No. 7, 2019 https://doi.org/10.1007/s11664-019-07191-w Ó 2019 The Minerals, Metals & Materials Society 4265