Abstract: Band structure and density of states of yttrium ,zirconium and niobium doped single-layer MoS 2 are studied by first principles method .It is found that the bond length of impurity atoms is distorted by yttrium, zirconium and niobium doped monolayer MoS 2 in the Molybdenum position , but the distortion rate of yttrium doped system is the largest .Through the study of yttrium , zirconium and niobium co-doped system, that we can get the conductive property of monolayer MoS 2 was improved by yttrium ,zirconium co-doping;the yttrium and niobium co-doped sites are easy to be the electron trapping centers the reason for the Fermi energy passes through the impurity levels and the energy level is half full .There are many impurity levels in the band gap in zirconium and niobium co-doped system , as well as conduction band energy move to high energy region .Electronic structure of monolayer MoS 2 were changed in the co-doped systems.

Key words: Band structure and density of states of yttrium ,zirconium and niobium doped single-layer MoS 2 are studied by first principles method .It is found that the bond length of impurity atoms is distorted by yttrium, zirconium and niobium doped monolayer MoS 2 in the Molybdenum position , but the distortion rate of yttrium doped system is the largest .Through the study of yttrium , zirconium and niobium co-doped system, that we can get the conductive property of monolayer MoS 2 was improved by yttrium ,zirconium co-doping;the yttrium and niobium co-doped sites are easy to be the electron trapping centers the reason for the Fermi energy passes through the impurity levels and the energy level is half full .There are many impurity levels in the band gap in zirconium and niobium co-doped system , as well as conduction band energy move to high energy region .Electronic structure of monolayer MoS 2 were changed in the co-doped systems.