Study Of Electronic Structure And Magnetic Property Of Mn-doped ZnO Quantum Wires

With the rise of the third revolution of science and technology and the development of science and technology, our knowledge of the microscopic world is increasingly fine. Now we even can be achieved in levels of-1510 m with the decrease of the scales. Because of its outstanding physical properties, nanometer materials were received extensive attention of the scientific community. As the traditional direct band gap wide band gap semiconductor material, in many fields such as photoelectric、piezoelectric、thermoelectric and ferroelectric Zn O has its unique properties. It has enormous potential applications and research value. People on the microscopic study of nano semiconductor material contains two dimensional quantum well、One dimensional quantum wire、zero dimensional quantum dots or quantum ring.In modern times, Zn O dilute magnetic semiconductor, with its huge potential application prospect in spintronics caused wide attention of many researchers in the world. So many related theory and experimental results has been reported. There have many research achievements in the quantum well quantum dots and quantum ring, but in the study of nanowires is relatively small. This dissertation focus on the research on electronic structures of quantum wires of Zn O. In addition, we also studied its impact under magnetic field. Besides, this dissertation also analyzes the change of the valence band of the manganese doped Zn O dilute magnetic semiconductor nanowires in the magnetic field, and also studied some magneto optical properties of the material in the magnetic field. Some problems and conclusions are studied as follows in this dissertation.(1) The first chapter mainly described the development of nanometer materials, showing the significance of the research. This chapter mainly illustrates the characteristics of the nature of the Zn O and dilutes magnetic semiconductors, as well as some theories which were used in this dissertation.(2) In his chapter, the detailed calculation process of some theoretical models were given, including k·p perturbation method to calculate band structure、effective mass theory.(3) The third chapter mainly calculated the band structure of Zn O quantum wires. First, based on the framework of the effective-mass theory, the Hamiltonians of the electron and hole states of the wurtzite structure in the magnetic field are derived. By solving the Shrodinger equation, 10 lowest valence subbands are plotted with different hJ values. All valence subbands are found to be double degenerate. The applied magnetic field can split the degenerate valence subbands.(4) The fourth chapter mainly studies the electronic structure and magnetic properties of Mn doped Zn O nanowires. The electron states and hole states of Mn-doped Zn O nanowires in the magnetic field are calculated based on the six-band k·p effective-mass theory. 10 lowest valence subbands with differenthJ are calculated by the Bessel function expanding method. All valence subbands are found to be non-degenerate in the magnetic field, the hole states with positivehJ will reverse, while they will not reverse with negativehJ when the magnetic field is applied. The several lowest magneto-absorption spectra of Mn-doped Zn O nanowires at the G point are labeled in the second half of this chapter. Through the analysis, the number of the absorption peaks will increase with the increment the carrier density and the temperature. It is also found that the quasi-Fermi level of the conduction band is almost not changed by the doped concentration of manganese ions, but the quasi-Fermi level of the valence band increase with the increase of the concentration of manganese ions.