First-Principles Study of Adsorption of Halogen Molecules on Graphene-MoS2 Bilayer Hetero-system

S Lamichhane,N P Adhikari,B Sanyal,N Pantha,P Lage,G B Khatri

doi:10.1088/1742-6596/765/1/012011

Abstract

We have performed density functional theory based first-principles calculations to study the stability, geometrical structures and electronic properties of pure 3×3 supercell of MoS2, 4×4 supercell of graphene, graphene-MoS2 bilayer heterosystem, F2, Cl2, Br2 and I2 molecules on hetero-system within the DFT- D2 level of approximations. The preferable site and adsorption energy of halogen molecules are studied. The most stable geometries are considered to study their electronic band structure, Density of states and magnetic properties with reference to individual 2D components, graphene and MoS2.

Highlights

The strongest, thinnest and most stretchable material arranged in honeycomb lattice of thick sheet of sp2-bonded carbon atoms termed as graphene is at focus of many research works worldwide due to its peculiar properties like observable quantum Hall effect at room temperature and existence of twodimensional gas of massless Dirac fermions [1,2,3,4,5]
From table [3], it is clearly seen that the band gap of 0.375 eV is found in the case of fluorine atoms adsorbed graphene-MoS2 bilayer but in other halogen adsorbed bilayer, Dirac point shifted above the Fermi level
The plot of density of states (DOS) shows that both up-DOS and down-DOS are symmetrical about the axis in grapheneMoS2 bilayer hetero-system as well as halogen molecules adsorbed bilayer hetero-structures

Summary

Introduction

The strongest, thinnest and most stretchable material arranged in honeycomb lattice of thick sheet of sp2-bonded carbon atoms termed as graphene is at focus of many research works worldwide due to its peculiar properties like observable quantum Hall effect at room temperature and existence of twodimensional gas of massless Dirac fermions [1,2,3,4,5]. Since MoS2 is band gap material, we are interested to test halogens on graphene-MoS2 bilayer to obtain high band gaps and the role of fluorine to change the electronic structure From both scientific and technological point of view, investigation of halogen adsorption on semiconducting surface is very important as halogen and its compounds are widely used in the etching technologies. Figure 1: 3×3 supercell of MoS2 Monolayer and 4×4 super cell of graphene to form a MoS2 -graphene bilayer hetero-system, (a) Top-view and (b) Side-view respectively

Computational Details

Adsorption of halogen molecules on Graphene-MoS2 bilayer hetero-structure

Electronic structure calculations

Conclusions