AuCl₃ Molecule And N Atom Dual-doped Graphene: A First-principles Study

Graphene,a two-dimensional?2D?monolayer structure of carbon,has attracted intense attention since its first successful preparation in 2004.Graphene has been widely used in many applications due to unique physicochemical and electrical properties.Though graphene has excellent electrical properties,the zero band gap prevented its application like semiconductor materials.Thus,researchers have studied the methods to open the band gap of graphene.Dual-doping with donors and acceptors is a good way to open the band gap of graphene.Especially,B-N dual doping has been investigated by many researchers,because the radii of B and N atom are similar with that of C atom.However,B acceptors and N donors are both substitutional defects.Dual doping with high concentration may strongly degrade the lattice integrity of graphene and decrease the electrical properties such as carrier mobility.AuCl₃ is an acceptor-like molecule for graphene and does not substitute the C atoms,because the Au3+ ions can be reduced to Au clusters through a charge transfer from the graphene surface.Thus,the N-AuCl₃ dual doping may provide a way to open the band gap of graphene with less substitutional defects.And that there has few calculation studies on the band-gap tuning of graphene by N-AuCl₃ dual doping.In this paper,the band-gap tuning of graphene by AuCl₃-acceptor and N-donor dual doping were studied using the first-principle calculations.First,We used three 7×7×1 supercell of graphenes,carbon atom were substituted by nitrogen atom and then AuCl₃ molecule were adsorbed on the surface of graphene.The Au-N distances for the three models were 3.857,5.561 and 6.731 ?,respectively.Results show that the band-gaps of graphenes are successfully opened by comparing with the pristine graphene.Three supercell models of dual-doped graphenes were calculated for comparison.The band structures,the density of states?DOS?,the partial density of states?PDOS?,the formation energies?Eform?and the charge densities of the three supercell models were comprehensively investigated.Through calculation,we get the following conclusions: Firstly,with the increasing of dAu-N,the band-gap width of graphene decreases,however,the work function and Eform of graphene increase.Secondly,the dual-doped graphene with the smallest dAu-N of 3.857 ? shows a largest band-gap width of 0.396 eV and a lowest Eform of 0.4547 eV.Thirdly,with the increasing of dAu-N,the changes of band-gap width and Fermi level are attributed to the charge change between N,AuCl₃ and graphene.Fourthly,the change of the Eform is originated from the variations of LC-N and LC-C caused by the interaction between AuCl₃ and graphene.