Impurity Effects On The Electronic Structures Of MoSe₂ And ZrS₂ Monolayers

Two-dimensional graphene-like nanomaterials have attracted more and more researchers'attention,since the Geim,Konstantin and their collaborators successfully produced graphene by mechanical stripping for the first time in 2004.Due to the excellent electronic and magnetic properties,they are widely used in the field of optoelectronics such as solar cells,light-emitting diodes and spin devices.In this paper,the first-principles calculation method based on density functional theory is used to study the electronic structures of MoSe₂ and ZrS₂ monolayers.In addition,the impurity characteristics,electronic structure,formation energy and transition level of the systems are investigated by substituting group V?N,P,and As?and VII?F,Cl,Br and I?for S atom.The related results are as follows.?1?For the investigation of electronic structure in N,P,and As-doped MoSe₂ monolayer,the results indicate that all doped cases exhibit p-type doping.With the increasing of atomic radius,the formation energy increases and the transition energy decreases and the group-V doped system are easier to realize under Mo-rich.In addition to the As doping system,the magnetic states of other systems are induced due to the introduction of dopant atoms.?2?For the F-,Cl-,Br-and I-doped MoSe₂ monolayer,the results indicate the n-type conductivity may be engineered with the group VII atoms doped MoSe₂ systems.With the increasing of atomic number,the formation energy and transition levels increase.In particular,F impurity atom can offer effective n-type carriers in MoSe₂ monolayer.?3?For the investigation of ZrS₂ monolayer,numerical results also suggest that N-,P-or As-doping is effective for p-type conductivity.The formation energy increases with increasing impurity atom size for each doped case.It is relatively easier to incorporate impurity atoms under Zr-rich experimental situation.?4?For the F-,Cl-,Br-and I-doped ZrS₂ monolayer,the results indicate impuritie atoms are suitable as n-type carriers.With the increasingv of atomic radius,the formation energy and transition levels increase.From the optical parameters we have obtained,one can conclude the optical absorption coefficient of pristine ZrS₂ monolayer is relatively low.In the range of visible spectrum,the effect of optical absorption is weak,which shows that the pristine ZrS₂ monolayer is transparent.After doping of the V and VII atoms,the systems remain transparent.In particular,the absorption edge shows red shift of the As-doped ZrS₂ monolayer.