二维磷化硼多层材料理论研究

发布时间：2018-02-14 18:33

本文关键词： 密度泛函理论二维磷化硼电子结构载流子迁移率光学吸收谱太阳能电池　出处：《中国科学技术大学》2015年硕士论文　论文类型：学位论文

【摘要】：纳米材料是在三个维度上至少有一个维度的几何尺寸介于1nm到100nm之间的材料,会出现一些在体相中所观察不到的奇异的物理与化学性质以及微观量子现象,从而加深了人们对自然世界的认识,同时也大大地拓宽了新的运用领域。纳米材料的运用已遍及了各个领域,其中主要有纳米半导体、纳米磁性、纳米催化、纳米计算机、以及医疗上的应用等。由纳米材料所引发的纳米科技极大地促进社会进步和经济发展,而且随着时代的发展这种影响将会越来越大,并逐渐渗入人们生活的方方面面。因而纳米材料研究价值非常大。自从石墨烯被合成出之后,由于其特殊优异的化学物理性质,引发低维材料的研究热潮。后来相继的有第四主族的硅烯、锗烯,三五主族的六方氮化硼,过渡金属硫化物,和第五主族的磷烯等二维纳米材料,作为在光电器件和电子器件等半导体器件方面的潜在应用,而相继被研究。最近另一个二维材料磷化硼也逐渐引起大家的注意,虽然没有被实验合成出,但最近已有实验在硅的表面上合成出了磷化硼薄膜,且已有相关的理论方面的文章对其稳定性和器件方面的应用有了一定的研究。通过我们的计算,发现二维磷化硼在半导体器件方面有着优异的综合性质,并将有着广泛的运用前景。从头算第一性原理密度泛函理论已经成为研究纳米材料的一种重要的研究手段。在此篇论文中,我们主要用了密度泛函理论的方法,来研究二维磷化硼多层材料的各种化学物理性质。第一章简要介绍了第一性原理密度泛函的开创与发展。密度泛函理论是将电子密度替换波函数作为研究的基本量,并将各个参量都看作是基态电子密度的函数来处理。由于电子密度只具有三个维度,从而在实际运用上与概念上都更为方便地处理。与波函数相较而言,电子密度大大地减小了计算量和节省了计算资源。此外密度泛函理论在许多方面有了很大的发展,并取得了一定的成功,尤其是对已知结构材料的各种基态性质的相关研究。最后介绍了与密度泛函有关的一些计算软件包。第二章首先研究磷化硼体相的原子和电子结构信息,与实验参数进行比较,从而确定计算方法。接着计算了单层磷化硼的结构信息及其稳定性,然后通过解离能的计算确定了二维磷化硼从体相中剥离出后其层数的可能性。紧接着我们研究了多层磷化硼和体相磷化硼的电子结构,并据此计算了多层磷化硼的载流子输运和光学吸收性质,最后计算了二维磷化硼体系的化学稳定性和在空气中的化学惰性。通过这一系列的计算,发现二维磷化硼体系在半导体器件方面有着其它已知二维材料所不具有的综合的优异性质,因此具有极其广阔的运用前景。
[Abstract]:Nanomaterials are materials with at least one dimension in three dimensions ranging in size from 1 nm to 100 nm, resulting in strange physical and chemical properties and microscopic quantum phenomena that are not observed in the physical phase. This has deepened people's understanding of the natural world, and at the same time greatly broadened the new fields of application. Nanomaterials have been widely used in various fields, including nano-semiconductors, nanomagnetic, nano-catalysis, nano-computers, Nanotechnology triggered by nanomaterials has greatly promoted social progress and economic development, and with the development of the times this impact will become greater and greater. And gradually infiltrated into all aspects of people's lives, so the research value of nanomaterials is very great. Since the synthesis of graphene, due to its special excellent chemical and physical properties, it has triggered a research boom in low-dimensional materials. Later, there were 4th main groups of silicene, germane, hexagonal boron nitride, transition metal sulfides, As potential applications in semiconductor devices such as optoelectronic devices and electronic devices, two dimensional nanomaterials, such as phosphorene and 5th, have been studied one after another. Recently, another two-dimensional material, boron phosphide, has attracted more and more attention. Although it has not been synthesized by experiments, we have recently synthesized boron phosphide films on the surface of silicon, and some related theoretical articles have studied its stability and device applications. It is found that two dimensional boron phosphates have excellent comprehensive properties in semiconductor devices and will have a wide application prospect. The ab initio first principles density functional theory (DFT) has become an important research tool for the study of nanomaterials. In this paper, we mainly use the DFT method. To study the chemical and physical properties of two-dimensional boron phosphating multilayer materials. The first chapter briefly introduces the creation and development of the first principle density functional. The density functional theory takes the electron density substitution wave function as the basic research quantity. Each parameter is treated as a function of the ground state electron density. Because the electron density has only three dimensions, it is more convenient to process in practice and conceptually. Compared with the wave function, The electron density has greatly reduced the computational cost and saved the computational resources. In addition, the density functional theory has developed greatly in many aspects, and has achieved certain success. In particular, the properties of various ground states of known structural materials are studied. Finally, some calculation software packages related to density functional are introduced. In the second chapter, the atomic and electronic structure information of boron phosphating phase is studied, and compared with the experimental parameters, the calculation method is determined, and then the structure information and stability of monolayer boron phosphine are calculated. Then the possibility of the number of layers after the two dimensional boron phosphide is removed from the bulk phase is determined by the calculation of dissociation energy. Then we study the electronic structure of multilayer boron phosphate and bulk boron phosphate. The carrier transport and optical absorption properties of multilayer boron phosphide are calculated. Finally, the chemical stability and chemical inertia in air of two-dimensional boron phosphate system are calculated. It is found that the two-dimensional boron phosphating system has excellent properties which other known two-dimensional materials do not have in semiconductor devices, so it has a very broad application prospect.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O613.81

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