Electronic And Optical Properties Analysis On Doped ZnS

ZnS is an important direct-photon-transition semiconductor material in?-? group chalcogenide with energy gap of 3.68 e V which have two different structures blende and wurtzite.Because of the thermal infrared transparency,good electroluminescent phosphor function and effect,it has been widely used in the preparation of optoelectronic devices and optical catalysis.However,there are some limitations of pure ZnS material to improve to solve some certain and pratical questions,so we use first-principles density functional theory which based on doped ZnS to improve the lattice structure,electrical properties and optical properties of ZnS,in order to adapt the actual needs in the real sense.The paper includes the following seven parts.Structure and basic research status and the nature and significance of the first chapter introduces the ZnS.The second chapter introduces the research articles used by the theoretical basis and computational tools doped ZnS.The third chapter,a single mineral doping and some minerals co-doping ZnS lattice structure,electronic structure,optical properties are discussed in detail.The fourth chapter,detailed analysis the lattice parameters electronic structure,optical properties of the main transition metal TM(Sc,Mn,Mo)-doped ZnS.The fifth chapter introduces the lattice structure,electronic structure,optical properties of pure and doped ZnS nanotube.The sixth chapter,emphatically analyzed the lattice structure,electronic structure,optical properties of three different crystalline phases of ZnS surface structure.Through the study found that 1.(1)the state of Ag 4d mainly contribute to the valence band and form a wave crest in adjacent zero of energy;N doping realized the P-type doping of ZnS and greatly improved the optical properties of ZnS.(2)Na doping has realized the P-type doping of ZnS,made the light absorption edge occur red shift in optics together with Cl,Na co-doped ZnS,meanwhile,Cl doping lead to blue shift.(3)Ga single doping and Ga,O co-doping made the zero of energy move into the conduction band which illustrates the Ga doping changes the conduction type of ZnS to N-type.2.Transition metal TM(Sc,Mn,Mo)doping form multiple impurity level near the Fermi level;TM doping makes the Fermi level into the conduction band which forming a degenerate semiconductor with a half-metallic property;Mn,Mo doping lead to a red shift while Sc doping appear blue shift phenomenon in the absorption curve.3.The state 3p from Cl broke the original p-d hybridized orbit located at the top of the valence band of ZnS nanotube,and Cl1-has less electron than S2-which was been replaced.Therefore,Cl doping introduced redundant carrier-hole at the top of the valence band in ZnS nanotube,so realize P-type doping of ZnS nanotube.Mn doping form some impurity levels near the Fermi level which may due to Mn doping which produce new donor levels in the energy levels.4.ZnS(110)surface structure administered the largest forbidden band width which suitable for wide band gap surface structure device;ZnS(100)own the smallest forbidden band width and very intense level in the bottom of the conduction band which present the strongest electrical conductivity.All phase of Zn S surface structures have a good absorption capacity toward UV around 100-300 nm,including that ZnS(100)surface structure has the most widely absorption range and ZnS(111)surface structure own the largest absorption intensity.