新型二维半导体材料磷烯吸附原子的性质研究
发布时间：2018-11-13 19:00
【摘要】：表面原子吸附是改变半导体材料物理和化学性质的最有效的方法之一。将金属或非金属原子吸附到单层黑磷(磷烯“phosphorene”)材料的表面,可以引起磷烯的能带结构、电子态密度等电子结构和光学性质的改变。经过表面原子吸附处理的磷烯材料可以具有不同于本征磷烯的新特性,尤其是导电性和磁性的改变。基于量子力学和密度泛函理论的第一性原理的计算方法,是研究材料表面原子吸附的性能和微观结构变化的一种比较有效的方法。利用第一性原理的计算方法进行表面吸附研究,不但可以详细而又深入的了解磷烯材料的微观几何结构和其电子结构,从理论上验证一些实验现象的正确性和精确性,还可以探究材料的一些未知的特性,进而推进新材料的研发。本论文的研究工作主要分为以下几个部分:第一部分研究了本征磷烯(phosphorene)的原子结构、电子结构和磁性。单层黑磷的结构为正交结构,它的空间群为Cmca(No.64),是一种典型的直接带隙二维半导体材料。本文具体对其能带结构和电子态密度进行了详细的理论分析。计算结果验证了实验所得的磷烯所具有的物理特性的正确性。第二部分研究了磷烯表面吸附C、N、O、Na、Mg、Al原子的基本物理特性,包括最稳定吸附位置、体系的几何结构和电荷转移情况等,并对计算结果进行了系统的分析。磷烯与金属原子以及非金属原子之间的相互作用都比较强,吸附能也比较大。磷烯表面吸附非金属原子时,磷烯的P原子与非金属原子形成了作用力比较强的共价键。吸附金属原子时,其结合能比石墨烯的结合能要大得多,结构更加稳定。电子由金属原子转移到了磷烯表面,这在磷烯作为电池电极材料方面有积极的作用。最后分析了磷烯吸附不同的原子后,其体系的能带结构的变化和电子态密度随能量变化的规律。本文针对不同的吸附原子,计算得出了他们的能带结构图、总的态密度和分波态密度图,分阶段分析了磷烯体系态密度的来源。根据计算,吸附N、Na、Al原子时,磷烯材料由直接带隙性质的半导体转化成了导体。吸附C原子时,其体系比较特殊,由于自旋磁性的影响,材料的能带结构分为上下自旋能带,材料的性质仍为半导体。吸附Mg原子时,体系保持半导体特性,带隙比本征态时的带隙要小。由于Mg原子的加入,体系由直接带隙半导体转变为了间接带隙的半导体。吸附O原子时,体系同样保持半导体特性,O原子对体系能带以及态密度的影响很小,其能带结构与本征态的磷烯最为相似。通过对磷烯体系的系统分析,我们发现原子吸附影响磷烯特性发生改变的主要原因是不同原子间的相互作用和各不相同的电子转移情况。这些理论结论可以为磷烯的更深层次的研究提供有效的数据。
[Abstract]:Surface atomic adsorption is one of the most effective methods to change the physical and chemical properties of semiconductor materials. The adsorption of metal or nonmetallic atoms onto the surface of monolayer black phosphorus ("phosphorene") materials can result in the changes of the electronic structure and optical properties of phosphonene, such as the energy band structure, electronic density of states and so on. The Phosphorene materials treated by surface atomic adsorption can have new properties different from those of intrinsic phosphorene, especially the changes of electrical conductivity and magnetic properties. The first-principle calculation method based on quantum mechanics and density functional theory is an effective method to study the properties and microstructure of atomic adsorption on the surface of materials. The study of surface adsorption by first-principle calculation method can not only understand the microstructure and electronic structure of phosphoenes in detail, but also verify the correctness and accuracy of some experimental phenomena in theory. We can also explore some unknown properties of materials, and then promote the development of new materials. The work of this thesis is divided into the following parts: in the first part, the atomic structure, electronic structure and magnetic properties of (phosphorene) are studied. The structure of monolayer black phosphorus is orthogonal, and its space group is Cmca (No.64), which is a typical direct band-gap two-dimensional semiconductor material. In this paper, the band structure and electron density of states are analyzed in detail. The calculated results verify the correctness of the physical properties of the experimental phosphorene. In the second part, the basic physical properties of the surface adsorption of C _ (N) N _ (N) O _ (O) Na _ (2) MgO _ (Al) atom on the surface of phosphorene are studied, including the most stable adsorption position, the geometric structure and the charge transfer of the system, and the calculated results are systematically analyzed. The interaction of phosphorene with metal and nonmetallic atoms is stronger and the adsorption energy is larger. When nonmetallic atoms are adsorbed on the surface of phosphorene, P atoms of phosphorene form covalent bonds with nonmetallic atoms. When metal atoms are adsorbed, its binding energy is much larger than that of graphene, and its structure is more stable. Electrons are transferred from metal atoms to the surface of phosphorene, which plays an active role in the use of phosphorene as electrode material for batteries. Finally, the changes of the energy band structure and the density of states of the system with different atoms adsorbed by phosphorene were analyzed. In this paper, the energy band structure diagram, the total density of states and the partial density of states are calculated for different adsorbed atoms, and the source of the density of states in the phosphorene system is analyzed in stages. According to the calculation, the phosphene material is transformed from a semiconductor with direct band gap to a conductor when it adsorbs the N _ (N) Na ~ (2 +) Al atom. When C atom is adsorbed, the system is special. Due to the effect of spin magnetism, the energy band structure of the material can be divided into upper and lower spin bands, and the properties of the material are still semiconductors. When Mg atoms are adsorbed, the band gap of the system is smaller than that of the intrinsic state. Because of the addition of Mg atom, the system changed from direct band gap semiconductor to indirect band gap semiconductor. When O atoms are adsorbed, the semiconductor properties of the system are also maintained. The influence of O atoms on the energy band and the density of states of the system is very small, and the band structure of the system is most similar to that of phosphorene in the intrinsic state. Through the systematic analysis of the phosphorene system, we find that the main reason for the influence of atomic adsorption on the properties of phosphorene is the interaction between different atoms and the different electron transfer. These conclusions can provide effective data for the deeper study of phosphorene.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN304
本文编号：2330147
[Abstract]:Surface atomic adsorption is one of the most effective methods to change the physical and chemical properties of semiconductor materials. The adsorption of metal or nonmetallic atoms onto the surface of monolayer black phosphorus ("phosphorene") materials can result in the changes of the electronic structure and optical properties of phosphonene, such as the energy band structure, electronic density of states and so on. The Phosphorene materials treated by surface atomic adsorption can have new properties different from those of intrinsic phosphorene, especially the changes of electrical conductivity and magnetic properties. The first-principle calculation method based on quantum mechanics and density functional theory is an effective method to study the properties and microstructure of atomic adsorption on the surface of materials. The study of surface adsorption by first-principle calculation method can not only understand the microstructure and electronic structure of phosphoenes in detail, but also verify the correctness and accuracy of some experimental phenomena in theory. We can also explore some unknown properties of materials, and then promote the development of new materials. The work of this thesis is divided into the following parts: in the first part, the atomic structure, electronic structure and magnetic properties of (phosphorene) are studied. The structure of monolayer black phosphorus is orthogonal, and its space group is Cmca (No.64), which is a typical direct band-gap two-dimensional semiconductor material. In this paper, the band structure and electron density of states are analyzed in detail. The calculated results verify the correctness of the physical properties of the experimental phosphorene. In the second part, the basic physical properties of the surface adsorption of C _ (N) N _ (N) O _ (O) Na _ (2) MgO _ (Al) atom on the surface of phosphorene are studied, including the most stable adsorption position, the geometric structure and the charge transfer of the system, and the calculated results are systematically analyzed. The interaction of phosphorene with metal and nonmetallic atoms is stronger and the adsorption energy is larger. When nonmetallic atoms are adsorbed on the surface of phosphorene, P atoms of phosphorene form covalent bonds with nonmetallic atoms. When metal atoms are adsorbed, its binding energy is much larger than that of graphene, and its structure is more stable. Electrons are transferred from metal atoms to the surface of phosphorene, which plays an active role in the use of phosphorene as electrode material for batteries. Finally, the changes of the energy band structure and the density of states of the system with different atoms adsorbed by phosphorene were analyzed. In this paper, the energy band structure diagram, the total density of states and the partial density of states are calculated for different adsorbed atoms, and the source of the density of states in the phosphorene system is analyzed in stages. According to the calculation, the phosphene material is transformed from a semiconductor with direct band gap to a conductor when it adsorbs the N _ (N) Na ~ (2 +) Al atom. When C atom is adsorbed, the system is special. Due to the effect of spin magnetism, the energy band structure of the material can be divided into upper and lower spin bands, and the properties of the material are still semiconductors. When Mg atoms are adsorbed, the band gap of the system is smaller than that of the intrinsic state. Because of the addition of Mg atom, the system changed from direct band gap semiconductor to indirect band gap semiconductor. When O atoms are adsorbed, the semiconductor properties of the system are also maintained. The influence of O atoms on the energy band and the density of states of the system is very small, and the band structure of the system is most similar to that of phosphorene in the intrinsic state. Through the systematic analysis of the phosphorene system, we find that the main reason for the influence of atomic adsorption on the properties of phosphorene is the interaction between different atoms and the different electron transfer. These conclusions can provide effective data for the deeper study of phosphorene.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN304
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