砷化硼团簇论文：砷化硼及砷化铟团簇结构、稳定性和电子性质的理论研究

砷化硼团簇论文：砷化硼及砷化铟团簇结构、稳定性和电子性质
的理论研究
【中文摘要】III-V族低维半导体材料,在纳米光电子学、集成电路和纳米器件等方面有着极为重要的作用。

近几十年来,人们在
III-V族半导体薄膜、超晶格、纳米管和量子点的实验及理论研究中取得了巨大的进步,但截止目前,对于III-V族砷化硼和砷化铟在
1~200个原子范围内的研究却很有限。

为此,文章采用密度泛函理论(DFT)对砷化硼以及砷化铟半导体团簇的几何结构、稳定性和电子性质进行了研究。

首先,应用密度泛函理论的全电子方法优化得到了BnAsn (n=1-14)团簇基态几何结构,并对其稳定性和电子性质做了系统分析。

结果表明,当n=4时团簇的基态由二维平面结构过渡到三维立体,当n > 4时团簇的基态随尺寸的增加而形成以B原子与As原子交替排列的四元环和六元环为结构基元的笼状构型;具有高对称的富勒笼状结构B12As12为最稳定团簇;能隙的取值范围显示BnAsn
(n=1-14)团簇具有典型的半导体特征;BnAsn (n=1-14)团簇具有较强的分子特性和共价特性。

其次,采用密度泛函理论下的赝势方法优化得到了五种稳定的InnAsn (n=4-90)管状团簇。

通过研究发现,它们遵循着有趣的结构衍化规律,所有管状团簇在结构上都满足共同的分子通式Inpk/2As pk/2。

管状团簇的主要结构单元是两个相互平行的p边形,外加p个四元环以及h个六元环结构,其中h、p和原子层数k 满足关系:h=p×(k-2)/2。

管状团簇的HOMO、LUMO的电子分布特征揭
示了管状结构形成的内在原因,同时它也在微观层面上解释了实验中一维InAs纳米材料的生长机理。

最后,以稳定管状团簇的结构为基础,通过搭建原胞,在周期边界条件下优化得到了无限长InAs纳米管的
几何结构。

结果表明,无限长纳米管具有与管状团簇极为类似的构型,且能带结构的分析发现不同类型的纳米管都表现出宽带隙的半导体
特征。

研究结果对于深入理解砷化硼团簇以及砷化铟纳米管的结构衍化和电子性质提供了一定的帮助,为III-V族低维半导体材料的进一步实验研究提供可靠的理论依据。

【英文摘要】Low-dimension semiconductor materials of the III-V group is playing an important role in the fields, such as nano-optical electronics, molectron and nanodevice . For the past decades, theoretic and experimental study about the film, superlattice, nanotube and quantum dot of the III-V group semiconductor have achieved a great progress. However, by now, the investigation of boron arsenide and indium arsenide in 1 to 200 scope of the number of atoms is still very limited. Therefor, in this paper a study of the geometric, stability and electronic properties of boron arsenide and indium arsenide clusters, have been carried by density functional theory (DFT).First of all, the investigation of the lowest-energy structures, stabilities and electronic properties of BnAsn clusters (n=1-14) have been presented by means of the
density-functional theory. The results show that the
lowest-energy structures undergo a structural change from two-dimensional to three-dimensional when n=4. With the increase of the cluster size (n>4), the BnAsn clusters tend to adopt cage-like structures, which can be considered as being built from four-membered rings (4MRs) and six-membered
rings(6MRs). B12As12, a fullerene-like cage with high symmetry, is the most stable cluster. The results of PDOS analysis reveal that a distinct spd hybrid can be found at the vicinity of Fermi level, and there are strong molecular and covalent characteristic in the clusters.Moreover, the effective core potential density functional calculations are performed to explore a series of InnAsn tubelike clusters up to n=90. It is interesting that all of the tubelike structures comply with some common properties, such as the general molecular structural formula Inpk/2Aspk/2 and the common structure units —the parallel polygons, 4MRs and 6MRs. Size-dependent cluster properties such as binding energy, HOMO-LUMO gaps, Mulliken charges on atoms and frontier molecular orbital surfaces have been discussed. The electron density distributions of HOMO and LUMO indicate that the chemical activity of the tubelike clusters at the two ends is stronger, which makes the clusters
being conducive to grow longer. That is why we can get the
tube-like clusters.Finally, based on the stable tube-like
cluster structures, the same method have been employed to optimize the infinite InAs nanotubes (InAsNTs). Their atomic
and electronic band structures are presented. The results show
that one-dimensional InAsNTs can be prepared by proper assembly
of tubelike clusters to form semiconductors with large band gap.The results of these studies are helpful for us to understand the growth of the structures and electronic properties of the boron arsenide clusters and indium arsenide nanotubes. Furthermore, they can present theoretical credible basis for the further experimental study of the low-dimension semiconductor materials of the III-V group.
【关键词】砷化硼团簇砷化铟团簇密度泛函理论几何结构电
子性质
【英文关键词】Density Functional Theory Clusters Geometric Structures Electronic Properties
【目录】砷化硼及砷化铟团簇结构、稳定性和电子性质的理论研
究中文摘要3-4Abstract4-5 1 绪论8-16 1.1 团簇的定
义和基本性质8-10 1.1.1 团簇的定义8 1.1.2 团簇的基本性
质8-10 1.2 团簇研究的现状及研究意义10-11 1.3 Ⅲ-Ⅴ族砷
化物半导体团簇的研究现状11-14 1.3.1 研究背景
11-13 1.3.2 Ⅲ-Ⅴ族砷化物半导体团簇的研究现状13 1.3.3 砷化硼和砷化铟团簇的研究13-14 1.4 本论文的主要工作及意义14-16 2 理论基础和计算方法16-29 2.1 第一性原理
16-17 2.1.1 绝热近似16 2.1.2 Hartree-Fock 近似
16-17 2.2 密度泛函理论17-22 2.2.1 早期的Thomas-Fermi 模型18 2.2.2 Hohenberg-Kohn 定理18-20 2.2.3 Kohn-Sham 方程20-22 2.3 交换相关能泛函22-26 2.3.1 局域密度近似
22-25 2.3.2 广义梯度近似25 2.3.3 杂化密度泛函
25-26 2.4 Gaussian03 计算软件简介及基组选择26-29 2.4.1 Gaussian03 计算软件简介26 2.4.2 基组选择26-29 3
B_nAs_n(n=1-14)团簇结构和电子性质的密度泛函理论研究
29-40 3.1 引言29 3.2 计算方法29-30 3.3 结果分析与讨论30-38 3.3.1 B_nAs_n(n=1-14)团簇的最低能量结构及其演化规律30-33 3.3.2 B_nAs_n(n≤14)团簇稳定性及电子性质随尺寸的变化33-38 3.4 小结38-40 4 In_nAs_n(n=4-90)管状团簇和InAs 无限长纳米管的结构、稳定性和电子性质40-53 4.1 引言40 4.2 计算方法40-41 4.3 结果与分析41-52 4.3.1
In_nAs_n (n=4-90)管状团簇的结构41-44 4.3.2 In_nAs_n管状团簇稳定性及电子性质随尺寸的变化44-49 4.3.3 无限长InA_s 纳米管的结构与性质49-52 4.4 本章小结52-53总结与展望
53-55参考文献55-63在读期间发表的论文63-64后记
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