石墨烯和硅烯等二维纳米材料表界面的理论研究

发布时间：2018-03-10 09:39

本文选题：石墨烯　切入点：硅烯　出处：《苏州大学》2015年硕士论文　论文类型：学位论文

【摘要】：自2004年十月英国Manchester大学的康斯坦汀·诺沃肖洛夫(Konstantin Novoselov)和安德烈·海姆(Andre Geim)等人通过采用胶带反复剥离石墨的简单方法首次获得独立存在的石墨烯[1]以来,它以独特的电子结构和优异的电学性能迅速成为材料科学领域一颗耀眼的新星[2-5]。然而石墨烯的价带(π电子)和导带(π*电子)相交于费米能级处,使得石墨烯成为带隙为0的半导体,限制了它在纳米电子器件中的应用。本文采用第一性原理的密度泛函理论通过石墨烯和硅烯的表界面调控,来提高石墨烯和硅烯的应用潜能。一、石墨烯与硅基底的相互作用及其电学性能调控。我们采用第一性原理研究了单层和双层石墨烯与氢钝化和非钝化的Si(111)/Si(100)表面的结合情况。我们发现氢钝化的Si表面Si(111)/Si(100)并没有影响石墨烯的电学和光学性质,然而,由于非钝化的Si基底对石墨烯的不同位置产生了强烈的相互作用,这使得石墨烯的对称性遭到破坏,使得石墨烯在狄拉克点的位置打开了一定的带隙。当Si表面用氢钝化后与石墨烯的结合能力则大大降低。对于双层石墨烯,我们发现下层石墨烯与Si基底具有较强的相互作用并在界面形成了共价键。对于双层石墨烯覆盖的情况,下层充当了缓冲层的作用,它与基底产生了共价相互作用,原有石墨烯的本征电子结构发生了改变,上层石墨烯与下层石墨烯之间是范德华相互作用,这层石墨烯基本上保留了其本征电子结构。我们的结果给出了石墨烯和重要的半导体材料-硅之间的相互作用机制,这对于石墨烯在微电子学中的应用具有重要意义。二、Ni(111)界面上石墨烯的生长及硅插层。受石墨烯热潮的影响,其副本——蜂窝状结构的硅单层,即硅烯(silicene)最近也引起了人们的广泛关注。我们采用范德华力修正过的第一性原理研究了在Ni(111)表面上单层石墨烯的吸附及硅插层的结构和性质。我们发现由于插层过程在石墨烯和Ni(111)基底之间形成了一个低翘曲度的二维蜂窝状Si层。Si嵌入graphene/Ni(111)体系结构优化完成后,石墨烯层从基底上脱离出来形成freestanding graphene。由于石墨烯覆盖层的保护作用从而使不稳定的Si插层表现出很高的稳定性。我们的这一理论结果对于在其他金属表面制备高质量的silicene提供了一个新的思路。
[Abstract]:Since October 2004, when Konstantin Novoselovo and Andre Heimm of Manchester University in the United Kingdom, et al., first obtained independent graphene by repeatedly stripping off graphite with tape. Because of its unique electronic structure and excellent electrical properties, it has rapidly become a dazzling new star in the field of material science [2-5]. However, the valence band (蟺 electron) and the conduction band (蟺 * electron) of graphene intersect at the Fermi level. Graphene becomes a semiconductor with a band gap of 0, which limits its application in nanoscale electronic devices. In this paper, the first principle density functional theory is used to regulate the interface between graphene and silicene. To improve the application potential of graphene and silicene. The interaction of graphene with silicon substrate and the regulation of its electrical properties. We have studied the bonding of single and double graphene with hydrogen passivated and non-passivated Si (111 / / Si ~ (10)) surface by first principles. We have found that the hydrogen passivated Si surface. There is no effect on the electrical and optical properties of graphene. However, the symmetry of graphene is destroyed because the non-passivated Si substrate strongly interacts with graphene at different positions. When Si surface is passivated with hydrogen, the binding ability of graphene to graphene is greatly reduced. We find that the lower layer of graphene interacts strongly with Si substrate and forms covalent bonds at the interface. In the case of double layer graphene covering, the lower layer acts as a buffer layer, and it has covalent interaction with the substrate. The intrinsic electronic structure of the original graphene has changed, and the interaction between the upper graphene and the lower graphene is van der Waals interaction. This layer of graphene basically retains its intrinsic electronic structure. Our results show the mechanism of interaction between graphene and an important semiconductor material, silicon. This is of great significance for the application of graphene in microelectronics. Silicene has also attracted much attention recently. We have studied the adsorption of graphene monolayer and the structure and properties of silicon intercalation on NiC111 surface by using the first principle modified by van der Waals force. We find that the structure and properties of the intercalation. A 2-D honeycomb Si layer with low warp was formed between graphene and NiC111) substrate. The structure of the system was optimized after the structure was optimized. The graphene layer is separated from the substrate to form freestanding graphene. The unstable Si intercalation exhibits high stability due to the protective effect of the graphene coating. Our theoretical results are very high for the preparation of other metal surfaces. Quality silicene provides a new way of thinking.
【学位授予单位】：苏州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O613.7

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