Mn掺杂ZnO量子线的电子结构及磁学性质研究

发布时间：2018-09-02 09:30

【摘要】：随着第三次科技革命的兴起与科技的发展,人类对微观世界的认知日渐精细,目前已经可以达到-1510 m的水平。随着尺度上的减小,纳米材料以其独特的物理性质受到科学界的广泛关注。氧化锌作为传统的宽禁带直接带隙半导体材料,其在光电、压电、热电和铁电等诸多领域都有其独特的性能,其具有非常巨大的应用潜力和研究价值。人们在微观上对纳米半导体材料的研究包含了二维量子阱、一维量子线、零维量子点或量子环。近代以来,Zn O基稀磁半导体以其在自旋电子学中巨大的潜在应用前景引起了世界上众多科研工作者的广泛关注。相关的理论和实验结果不断得到报道。在量子阱、量子点和量子环方面科学界已经有了非常丰富的研究成果,但是在量子线的研究方面却相对较少。本文紧密围绕Zn O量子线的电子结构这题问题展开,并探讨其在磁场下所受到的影响,除此之外,本文还分析了锰掺杂氧化锌稀磁半导体量子线在磁场中价带能带的变化情况,并研究了该材料在磁场中表现出来的一些磁光性质。本文主要解决的问题和得到的结论如下:(1)第一章阐述纳米材料的发展历程,展示其研究的意义。本章主要就Zn O和稀磁半导体的性质、特点进行简单说明,以及对本文用到的一些理论进行简单阐述。(2)第二章主要将论文中运用的理论模型进行详细的推导,包括k·p微扰法计算能带结构、有效质量理论。(3)第三章主要计算Zn O量子线的能带结构。首先以效质量近似为基础推导出纤锌矿空态和电子态的哈密顿量,通过解薛定谔方程,求出几个不同角动量hJ时10个最低的价带子带。通过对比B=0T和B=20T时能带变化可知,在无磁场下所有的价带子带都是双重简并的,当加入磁场后简并态会发生劈裂。(4)第四章主要研究了Mn掺杂Zn O量子线的电子结构和磁学性质。本章以六带k·p微扰有效质量理论为基础求得磁场下Mn掺杂Zn O量子线的电子和空穴态,利用贝塞尔函数展开法求解薛定谔方程,进而计算出不同角动量hJ下10个最低的价带子带。我们发现,所有的价带子带在磁场下将不再简并。此外,我们还发现,在磁场B不为0时,所有hJ为正的空穴态将发生反转,为负时不会发生反转。在本章的后半部分,我们计算并绘制了Mn掺杂Zn O量子线在?点附近一些低能量的磁吸收谱,通过对比分析,我们发现吸收峰的数量会随着载流子浓度和温度的升高而变多。在计算准费米能级时发现,Mn掺杂Zn O量子线导带的准费米能级不随Mn离子浓度的变化而发生改变,但价带的准费米能级却会随着Mn离子浓度的增加而增大。
[Abstract]:With the rise of the third science and technology revolution and the development of science and technology, the cognition of the microcosm is becoming more and more fine, and it can reach the level of -1510 m at present. With the decrease of scale, nanomaterials have attracted wide attention due to their unique physical properties. As a traditional wide bandgap semiconductor, zinc oxide has its unique properties in many fields, such as photoelectricity, piezoelectric, thermoelectricity and ferroelectricity. It has great application potential and research value. The study of nanoscale semiconductor materials includes two dimensional quantum well, one dimensional quantum wire, zero dimensional quantum dot or quantum ring. Since modern times, ZnO-based dilute magnetic semiconductors have attracted extensive attention of many researchers in the world for their great potential application in spin electronics. Relevant theoretical and experimental results have been continuously reported. In quantum wells, quantum dots and quantum rings, the scientific community has made a lot of achievements, but the research on quantum wires is relatively rare. In this paper, the electronic structure of Zn O quantum wire is discussed, and the influence of magnetic field on it is discussed. In addition, the variation of valence band in the magnetic field of manganese doped zinc oxide thin magnetic semiconductor quantum wire is analyzed. Some magneto-optic properties of the material in the magnetic field have been studied. The main problems and conclusions in this paper are as follows: (1) the development of nanomaterials is described in Chapter 1, and the significance of their research is demonstrated. In this chapter, the properties and characteristics of Zn O and dilute magnetic semiconductors are briefly explained, as well as some theories used in this paper. (2) in chapter 2, the theoretical models used in this paper are derived in detail. (3) in chapter 3, the energy band structure of Zn O quantum wire is calculated. Based on the effect mass approximation, the Hamiltonian of the empty and electronic states of wurtzite is first derived. By solving the Schrodinger equation, the 10 lowest valence bands with several different angular momentum hJ are obtained. By comparing the band changes of BC0T and BC20T, we can see that all valence band bands are doubly degenerate in the absence of magnetic field, and the simple parallel states will split when the magnetic field is added. (4) in chapter 4, the electronic structure and magnetic properties of Mn doped Zn O quantum wires are studied. In this chapter, the electron and hole states of Mn doped Zn O quantum wires under magnetic field are obtained based on the effective mass theory of six-band k p perturbation, and the Schrodinger equation is solved by Bessel function expansion method. Then 10 lowest valence bands with different angular momentum hJ are calculated. We find that all valence bands will no longer degenerate in a magnetic field. In addition, we also find that when the magnetic field B is not zero, all the hole states with positive hJ will be reversed, and no inversion will occur when the magnetic field B is negative. In the second half of this chapter, we have calculated and drawn Mn doped Zn O quantum wires in? By comparative analysis we find that the number of absorption peaks increases with the increase of carrier concentration and temperature. It is found that the quasi Fermi level of mn doped Zn O quantum wire does not change with the concentration of Mn ion, but the quasi Fermi level of valence band increases with the increase of Mn ion concentration.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN304.21

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