掺杂对若干类石墨烯材料纳米片电子结构的调制

发布时间：2018-05-16 14:17

本文选题：类石墨烯材料 + 掺杂　；参考：《河南师范大学》2015年硕士论文

【摘要】：自2004年石墨烯成功制备以来,二维类石墨烯材料因其具有独特的电学、光学和磁学等性质得到了大量的关注,被广泛应用于发光二极管、激光二极管、太阳能电池等光电子领域。然而,在二维类石墨烯材料的实际应用中还有一些问题亟待解决,如其n型和p型掺杂结构的稳定性及潜在物理性能等。本论文主要运用基于密度泛函理论的第一性原理计算方法研究类石墨烯结构的Al N、Ga S和Ga Se纳米片Mg掺杂的p型杂质特性,以及Sn S2纳米片的n型和p型掺杂对其电子结构、形成能和跃迁能级的影响,其主要内容和结果如下:1)对于Mg掺杂Al N纳米片中p型导电性的研究,数值结果显示Mg掺杂Al N纳米片的晶格常数、电子结构、形成能和跃迁能级与Mg掺杂浓度有密切关系。随着Mg掺杂浓度的逐渐增加,掺杂体系的晶格常数有显著增大,而(0/-1)电荷态之间的跃迁能级则单调地减小,且低于Mg掺杂Al N体材料的情况。这一有趣的结果显示了可以通过Mg掺杂浓度有效地调控Mg掺杂二维Al N纳米片的p型导电性。同时形成能的计算结果也显示了富氮环境下的形成能比富铝环境下的形成能更低,这意味着在富氮的环境下Mg更容易地取代二维Al N纳米片的Al原子。2)对于Mg掺杂二维Ga S和Ga Se纳米片中p型导电性的研究,数值结果显示了二维Ga S和Ga Se纳米片的晶格常数、电子结构、形成能和跃迁能级可以通过Mg掺杂浓度进行有效地调控。随着Mg掺杂浓度的逐渐增加,掺杂体系的晶格常数有显著增大,(0/-1)电荷态之间的跃迁能级则表现单调地减小的趋势。同时形成能的计算结果也显示了富硫或者富硒环境下的形成能比富镓环境下的形成能更低,这意味着在富硫或者富硒的环境下Mg取代二维Ga S和Ga Se纳米片中的Ga原子更为容易。3)对于V和VII族元素掺杂Sn S2二维纳米片的电子结构研究,数值结果显示了无论是V族还是VII族元素的掺杂,Sn S2纳米片的晶格常数均有明显的变化且掺杂体系的形成能均随杂质半径的增加而增加。V族元素掺杂体系的跃迁能级随杂质原子半径的增加而降低,而VII元素掺杂的型体系的跃迁能级却随杂质原子半径的增加而增加。其中N、P和As掺杂为p型受主深能级杂质,而F、Cl、Br和I的掺杂为n型施主浅能级杂质。而且,F掺杂的Sn S2纳米片中形成能和跃迁能级是最低的,因此F是最有效的n型施主杂质。此外,结果也显示所有的掺杂Sn S2纳米片在富锡的环境中更容易形成。这些结果为相关的实验研究和应用提供可靠的理论指导和参考。
[Abstract]:Since the successful preparation of graphene in 2004, two-dimensional graphene materials have been widely used in light emitting diodes (LEDs) and laser diodes (LEDs) because of their unique electrical, optical and magnetic properties. Solar cells and other areas of optoelectronics. However, there are still some problems to be solved in the practical application of two-dimensional graphene like materials, such as the stability and potential physical properties of n-type and p-type doped structures. In this paper, the first-principles method based on density functional theory is used to study the p-type impurity properties of graphene like Al _ (N) Ga _ S and Ga se nanocrystals doped with mg, and the electronic structure of Sn _ S _ 2 nanocrystals doped with n-type and p-type dopants. The main contents and results of the formation energy and transition energy levels are as follows: 1) the study of p-type conductivity in Mg-doped AlN nanocrystals shows the lattice constant and electronic structure of Mg-doped AlN nanocrystals. The formation energy and transition level are closely related to mg doping concentration. With the increasing of mg doping concentration, the lattice constant of the doped system increases significantly, while the transition energy level between 0 / -1) charge states decreases monotonously and is lower than that of Mg-doped Al-N bulk materials. This interesting result shows that the p-type electrical conductivity of Mg-doped two-dimensional Al N nanocrystals can be effectively regulated by mg doping concentration. At the same time, the calculation results of formation energy also show that the formation energy in nitrogen-rich environment is lower than that in Al-rich environment. This means that it is easier for mg to replace the Al atom. 2 of two-dimensional Al N nanoparticles in nitrogen-rich environment. The numerical results show that the lattice constants, electronic structure, formation energy and transition energy levels of two-dimensional Gas and GASE nanocrystals can be effectively regulated by mg doping concentration. With the increasing of mg doping concentration, the lattice constant of the doped system increases significantly, and the transition energy level between the charge states of the doped system decreases monotonously. At the same time, the calculation results of formation energy also show that the formation energy of rich sulfur or selenium rich environment is lower than that of gallium rich environment. This means that it is easier for mg to replace Ga atoms in two-dimensional Ga S and Ga se nanoliths in sulfur-rich or selenium-rich environments. The numerical results show that the lattice constants of doped Sn-S2 nanoliths of either V group or VII group elements have obvious changes, and the formation energy of doping system increases with the increase of impurity radius, and the transition of doping system of V group elements increases with the increase of impurity radius. The energy level decreases with the increase of the radius of the impurity atom. However, the transition energy levels of the type system doped with VII increase with the increase of the radius of the impurity atom. The doping of Nop-P and as is p-type acceptor deep level impurity, while the doping of FN Clnbr and I is n-type donor shallow level impurity. Moreover, the formation energy and transition energy level of F doped Sn S2 nanocrystals are the lowest, so F is the most effective n donor impurity. In addition, the results also show that all doped Sn S 2 nanocrystals are easier to form in tin rich environment. These results provide reliable theoretical guidance and reference for related experimental research and application.
【学位授予单位】：河南师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O613.71;TB383.1

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