Electronic Structure And Magnetic Properities Of ZnO Nanowires

ZnO nanowire is a direct band gap (3.35eV) semiconductor, has the high exciton binding energy (60meV), the unique surface effect, the small size effect and the quantum size effect. Therefore, exploring electronic structure and magnetic properties of ZnO nanowire has a very important significance.In this work, we will use the First-principle theory to discuss the magnetic and structure problems induced by Zn vacancies. Details as follows:1、Firstly we compared the electronic structure and magnetic properties of pure ZnO nanowires and nanowire containing Zn vacancies, in order to find out whether Zn vacancies can induce ferromagnetic or not. After research, it is found that the Zn vacancy can induce magnetism, and that the fierce p-p hybridization of O near the Zn vacancies responsible for the FM behavior. Then we calculated the formation energy of the system, found it was too high to ensure the system stable.2、Secondly, we calculated the electronic structure and magnetic properties of Li-doping in ZnO nanowires. From the density of states of Li doped ZnO nanowire, we find out that only Li doping can not induce any FM behaviors. But in the defects system of ZnO nanowire, Li doping can not only decrease the formation energy but also increase total magnetic moments. Because Li atom at the doping site can import hole carrier to the system, which can magnify the p-p hybridization of O near the Zn vacancies. In this way, Li doping in Zn vacancy ZnO nanowire system can stable the system and promote the total magnetic moments.