纳米结构二氧化锡材料光电性能的研究

发布时间：2018-04-03 23:10

本文选题：二氧化锡　切入点：第一性原理　出处：《济南大学》2015年硕士论文

【摘要】：二氧化锡(SnO2)材料是一种优秀的透明导电材料,也是一种典型的宽禁带半导体材料,常温下其带隙为3.6eV,这使得它在以SnO2为基的半导体材料工业方面具有很好的发展潜力。将SnO2制成低维纳米材料并对其进行掺杂后所形成的新的材料具有高导电性、高透光率、高紫外光吸收能力以及较强的红外反射率等性能,这更加拓宽了其在光电领域的应用价值。本论文以SnO2为基材料,运用基于密度泛函理论的第一性原理全电势线性缀加平面波法和投影缀加平面波法,在广义梯度近似(GGA)下伴随着PBE交换关联函数并应用Wien2k和VASP软件进行计算。首先,我们计算了本征态块体SnO2和Zr掺杂以及Zr、N共掺杂下SnO2材料的电子结构、能带和光学性质,研究结果表明掺杂Zr和N之后材料带隙减小,材料的导电性增强,并且光学吸收边发生红移,光学吸收能力也显著增强。其次在块体SnO2材料的基础上构建了“三明治”结构的单层SnO2纳米面模型,通过对其进行第一性原理GGA_PBE的计算表明,本征态SnO2纳米面的带隙要大于块体材料的带隙,其仍然为直接带隙半导体材料。然后我们对它进行了Ag掺杂和O缺陷的研究,结果表明Ag掺杂之后材料的带隙减小,导电性明显增强,光学性质的研究标明引入Ag之后材料在低能区域的吸收能力明显增强,并且随着Ag掺杂浓度的不同材料的吸收能力也有所不同。然后通过SnO2面构建出之字形(zigzag)和扶手椅形(armchair)的SnO2一维纳米带模型,研究了不同宽度下其带隙的变化并对其进行Ag掺杂的计算。研究结果表明SnO2纳米带是间接带隙半导体,随着纳米带宽度的增加,其带隙也随之发生变化,最后会趋向于一个稳定的值。当在纳米带中引入Ag之后,材料的导电性增强,光学性质的研究结果标明引入Ag之后材料在在低能区域有较强的吸收能力。最后我们通过对之字形SnO2纳米带和扶手椅形SnO2纳米带进行不同情况的H修饰来研究其电子结构和性质的变化,并且对其施加外部电场来调控其能带结构。研究结果显示H修饰前的之字形纳米带和扶手型纳米带的带隙均在电场调控下发生明显的变化,对其进行部分电荷密度的分析表明在电场作用下,材料表现出明显的stark效应。而H修饰后SnO2纳米带的带隙发生变化,并且在加电场后表现出比较弱的stark效应。更有趣的是,H修饰的之字形纳米带在外加电场的变化下出现了金属-半导体-金属的转变。最后我们计算了不同边缘构型的SnO2纳米带的输运特性,得到了一些有意义的结果。
[Abstract]:Sno _ 2) is an excellent transparent conductive material and a typical wide band gap semiconductor material with a band gap of 3.6 EV at room temperature, which makes it have a good development potential in semiconductor material industry based on SnO2.The new materials made of SnO2 and doped with SnO2 have high conductivity, high transmittance, high ultraviolet absorption ability and strong infrared reflectivity.This further broadens its application value in the field of optoelectronics.In this paper, based on SnO2, the first principle full potential linear plus plane wave method and projection plus plane wave method are used based on density functional theory.Under the generalized gradient approximation (GGA), the PBE commutative correlation function is accompanied and calculated by Wien2k and VASP software.First of all, we calculate the electronic structure, band and optical properties of SnO2 materials doped with SnO2 and Zr and ZrN co-doped. The results show that the band gap decreases and the electrical conductivity increases after doping Zr and N.And the optical absorption edge is redshift, and the optical absorption ability is also significantly enhanced.Secondly, the monolayer SnO2 nano-surface model of "sandwich" structure is constructed on the basis of bulk SnO2 material. The results of first-principles GGA_PBE calculation show that the band gap of intrinsic SnO2 nano-surface is larger than that of bulk SnO2 nanoplane.It is still a direct band gap semiconductor material.Then we study the Ag doping and O defects. The results show that the band gap decreases and the electrical conductivity increases obviously after Ag doping. The optical properties show that the absorption ability of the material in the low energy region is obviously enhanced after the introduction of Ag.And the absorption capacity of different Ag doped materials is different.Then the one-dimensional SnO2 nanobelts model of zigzag (zigzag) and armchair (armchair) were constructed by SnO2 plane. The band gap changes at different widths were studied and the Ag doping calculation was carried out.The results show that SnO2 nanobelts are indirect band-gap semiconductors. With the increase of the width of nanobelts, the band gap also changes and tends to a stable value.When Ag was introduced into nanobelts, the electrical conductivity of the materials was enhanced, and the results of optical properties showed that the materials had a strong absorption capacity in the low energy region after the introduction of Ag.Finally, we study the changes of electronic structure and properties of zigzag SnO2 nanoliths and armchair SnO2 nanoliths by H modification in different conditions, and apply external electric field to regulate their band structure.The results show that the band gap of zigzag and armrest nanobelts before H modification are obviously changed under the control of electric field. The analysis of partial charge density shows that the material exhibits obvious stark effect under the action of electric field.After H modification, the band gap of SnO2 nanobelts changes, and the stark effect is weaker after the addition of electric field.What is more interesting is that H-modified zigzag nanobelts change from metal to semiconductor to metal under the change of external electric field.Finally, we calculate the transport characteristics of SnO2 nanobelts with different edge configurations, and obtain some meaningful results.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;TQ134.32

【参考文献】