硅量子面表面键合的实验与计算研究

发布时间：2018-05-23 10:20

本文选题：硅量子面 + 表面键合　；参考：《贵州大学》2015年硕士论文

【摘要】：硅是微电子器件的主要材料,但由于硅的间接带隙的性质,其发光效率和强度都不高,使实现硅基光电子集成受到限制。但自从Canham在1990年研究发现多孔硅在室温下的PL强发光以来,硅基发光材料引起了人们的广泛兴趣和深入研究。材料的发光性能主要由其电子结构决定,可以通过杂质工程与能带工程来改变材料的带隙特征以提高其发光效率,主要有两种途径：一种是利用量子限制效应,另一种是引入表而发光中心。本文在不同氛围中的硅衬底上用PLD制备Si-Yb多层膜结构,发现在氮气氛围中制备的样品的EL发光具有明显的阈值行为,且随着膜层的增加,EL强度增强,这为制备硅基上的LED及量子级联激光器提供了新方法。在不同氛围中对纳米硅薄膜进行加工时,会在表面以键合形式产生表面态,本文将纳米硅薄膜看成是理想的二维硅量子面结构,其具有一维量子限制,使用Materials Studio软件构建模型,利用基于密度范函理论的第一性原理计算分析表而键合对硅量子面电子结构的影响,发现：量子面厚度、表面键合原子的密度和超晶胞对称性对能带的带隙值起决定作用,由此证明了量子限制效应和带隙变窄效应,并得到了对称性效应以及弯曲表面效应,并推测带隙宽度与晶面取向无关；表而态使带隙变窄是由于在带隙中产生了表面能级。这些都能在理论上为能带工程及纳米硅薄膜的发光增强提供参考。几乎所有的量子面的计算结果都呈现出准直接带隙特征,这可以有效提高硅材料的辐射复合效率。表面Si-Er键在带隙中产生了局域化的能级,可形成有效的发光中心,提高硅材料的发光效率。这是研发硅基LED和LD材料与器件的有效途径。
[Abstract]:Silicon is the main material of microelectronic devices, but because of the properties of the indirect band gap of silicon, its luminescence efficiency and intensity are not high, so the realization of silicon based optoelectronic integration is limited. However, since the PL luminescence of porous silicon at room temperature was discovered by Canham in 1990, the silicon-based luminescence materials have attracted extensive interest and in-depth study. The luminescence properties of materials are mainly determined by their electronic structures. The band gap characteristics of materials can be changed by impurity engineering and band engineering to improve their luminescence efficiency. There are two main ways to improve the luminescence efficiency: one is to make use of quantum confinement effect. The other is the introduction of a watch and the luminous center. In this paper, Si-Yb multilayer films were prepared on silicon substrates in different atmosphere by PLD. It was found that the El luminescence of the samples prepared in nitrogen atmosphere had obvious threshold behavior, and the El intensity increased with the increase of the film layer. This provides a new method for the fabrication of silicon based LED and quantum cascade lasers. In this paper, the nanocrystalline silicon film is regarded as an ideal two-dimensional silicon quantum surface structure, which has one-dimensional quantum limitation, and the model is constructed by using Materials Studio software, when the nanocrystalline silicon thin film is processed in different atmosphere, and the surface state is produced in the form of bonding. The influence of bonding on the electronic structure of silicon quantum surface is calculated by using the first principle analysis table based on density norm theory. It is found that the thickness of quantum surface, the density of surface bonding atom and the symmetry of supercell play a decisive role on the band gap value. It is proved that quantum confinement effect and band gap narrowing effect, symmetry effect and curved surface effect are obtained, and the band gap width is not related to the orientation of crystal plane, and the apparent state makes the band gap narrow because the surface energy level is produced in the band gap. All of these can provide a reference for energy band engineering and luminescence enhancement of nanocrystalline silicon thin films in theory. Almost all the results of quantum surface show quasi-direct band gap characteristics, which can effectively improve the radiation recombination efficiency of silicon materials. The surface Si-Er bond produces localized energy levels in the band gap, which can form effective luminescence centers and improve the luminescence efficiency of silicon materials. This is an effective way to develop silicon based LED and LD materials and devices.
【学位授予单位】：贵州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN304.12

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