The Realization Of Stable P Type ZnO And Inhibit The Self-compensation Effect Of Oxygen Vacancy Via Ag-S Codoping

As one of the typical wide band gap semiconductor materials, Zn O has superior performances, such as a strong ability to resist radiation and a higher exciton binding energy, which determines it, has broad application prospects in the field of optoelectronics, ferromagnetic, photosensitivity et al. Because of there are obviously self-compensation effects caused by plenty of native donor defects in Zn O, Zn O present unipolarity in impurity doping modification, it is extremely difficult to achieve for its p-type characteristics. And the acceptor level of p-type Zn O is always high, and the solid solubility of acceptor elements is relatively low. The p-type properties of Zn O cannot exist stably for a long time. The stability of p-type conversion for Zn O still restricts its practical application. Therefore the realization of stable and effective p-type Zn O is very significant in the field of photovoltaic applications.This article makes use of the first principles calculation based on density functional theory. It aims at the pervasive and relatively stable native donor defects in Zn O: oxygen vacancies(VO), designs a doping project for p-type Zn O which considering oxygen vacancy defects. This paper use substitutional impurity AgZn as an acceptor impurity which was formed by Ag atom replaces Zn atom. S atom is introduced to adjust the solid solubility of Ag in Zn O and reduce its acceptor level, and to some certain extant, inhibit the self-compensation effect of oxygen vacancy.In this paper, at first, it through research band structure and density of states of Ag doped ideal Zn O and Zn O with oxygen vacancy for the analysis of the internal mechanism of oxygen vacancy on self-compensation effect which impacts Ag doping. And then research the electronic structure of Zn O system by different concentration ratio of Ag, S, VO, to analyses the mechanism of inhibition of the self-compensation effect by oxygen vacancy and increase of the solid solubility of Ag and decrease of the acceptor level through introduced into S. Finally paper calculated the binding energy of impurity elements and the defect formation energy under different systems, to determine the effectiveness of p-type doped and system stability.The study found that through the introduction of S, it can assist Ag to realize the conversion of p-type Zn O, and at the same time, it can inhibit the self-compensation effect of oxygen vacancy and other adverse effects. The p-type conductive properties of Zn O can be ensured optimally when the concentration ratios of Ag, S, oxygen vacancy(VO) conform to 1:2:1.