The Investigation Of Oxygen Vacancy And Its Influence On Optical Properties In ZnO

ZnO is a multifunctional oxide material, has excellent performance in optical, piezoelectric, thermoelectric, ferroelectric and ferromagnetic fields. Particularly, as a wide band gap semiconductor optoelectronic materials, ZnO has got more and more attention for its excellent photoelectricity performance. It always has intrinsic point defects such as oxygen vacancy and zinc interstitial inevitablely because of its production process. Vacancy defect is an important semiconductor material defect which affecting the performance of this semiconductor by generating deep level to capture carrier.The purpose of this paper is to research on the structure and optical properties of ZnO with oxygen vacancy using ab initio numerical simulations of oxygen vacancy. The simulations are based upon the generalized gradient approximation on the density functional theory.First, this paper calculated the band structure, density of states. It is proved the reliability of our research through compared with othe papers that the oxygen vacancies leads to wider energy band gap.Second, this paper analysed the scattering mechanisms of oxygen vacancy conductivity properties. It is revealed that the appearance of oxygen vacancies leads to larger peak width and a new peak in lower energy in conductivity as compared to the intrinsic ZnO simulation. The study shows that the main mechanism influence conductivity is the ionized impurity scattering and proves that the positive state of oxygen vacancy is the stable state. We explained these unusual phenomena and analysed the conductivity changes with the scattering mechanisms in the semiconductors. The study shows that the main mechanism influence conductivity is the ionized impurity scattering and proves that the positive state of oxygen vacancy is the stable state.Finally, Polarization mechanism of the dielectric properties of oxygen vacancy (Vo) in ZnO is analysed. It is shown a obvious blue shift and a increase in the peak of dielectric function as compared to the intrinsic ZnO simulation. We analysed the dielectric changes with the polarization mechanism found that the main mechanism influence the dielectric properties is the electron displacement polarization. The result might be helpful for development of photoelectric materials.