Frist-Principles Calculation Of Electronic Structure And Lattice Dynamic Properties Of S-Doped Wurtzite ZnO

In this dissertation, the properties, applications, research significances and development prospects of wurtzite structure ZnO materials were introduced in first chapter mainly; the second chapter briefly introduces the computing method for the density functional theory; the electronic band calculation, density of state and phonon dispersion spectrum and phonon density of state wurtzite ZnO1-xSx compound were shown in third chapter by using CASTEP software package simulation based on the Density Functional Theory.At normal temperature, both wurtzite ZnO and ZnS are wide bandgap and direct band-gap semiconductor materials combined by photoelectricity and piezoelectricity. As they have many strengths such as lower equipment requirement, crystal growth with little difficulty, stable performance and so on. ZnO and ZnS are focused by researcher from home and broad. In the current experimental research field, some researches on ternary alloy ZnO1-xSx have been conducted. It is verified that the energy gap could be adjusted by doping S elements. Some theoretical researchers also conducted some researches on its electronic structures and optical properties. However, there are few researches on the lattice dynamic properties of wurtzite ZnO1-xSx. In this paper, the ultrasoft pseudopotentials under the LDA of the CASTEP software package are applied to research the electronic band structure and density of state of wurtzite ZnO1-xSx, and gained the phonon spectrum and phonon density of state by Norm-conserving pseudopotentials under the GGA. The numerical results shown that, the band gap of ZnO1-xSx decreases firstly and increased later with the increase of the doping content of S elements. The regular is in line with the experiment result. The result obtained by analyzing its TDOS and PDOS is that, the valence band of wurtzite ZnO1-xSx compound band is decided by2s2p state and3s3p of O and S as well as3d state of Zn, and the conduction band are formed by3s3p state of S and4s3p state of Zn. The information from the phonon spectrum of wurtzite ZnO1-xSx is that by increasing the doping content of S elements, it could be observed that the corresponding frequency value of the maximum frequency phonon mode will decrease. In the2×2×1super cell and16atoms of ZnO1-xSx, when the proportion of S elements of is the some but the location for O atom replacement is changed, apart from the gap width of the phonon density of state, it is the same in other aspects.