几种新型二维原子晶体材料的构筑及其结构特性
发布时间：2018-08-16 19:46
【摘要】：石墨烯,一种由碳原子构成的蜂窝状结构,自从在2004年被成功剥离之后就被广泛研究。单原子层厚度的石墨烯具有很多优良特性,例如:超高的载流子迁移率、超高的透光率、室温下的量子霍尔效应等,使其在电子学、光学、磁学、生物医学、催化、储能和传感器等领域有巨大的应用潜力,被公认为本世纪的“未来材料”和“革命性材料”。石墨烯的成功激励人们探索其他类石墨烯二维原子晶体材料,其中碳族二维材料(硅烯、锗烯和锡烯),非碳族二维材料(硼烯、铪烯、黑磷、过渡金属二硫属化合物和六方氮化硼)等也都在各自领域取得了很大成就。本论文主要利用超高真空低温扫描隧道显微镜(STM)、低能电子衍射(LEED)结合密度泛函理论(DFT)等研究手段探索几种新型类石墨烯二维原子晶体的生长,并对其结构和电子性质进行表征,具体如下:1.单层Mo Se2的边界结构研究。本工作中报道了利用分子束外延技术(MBE)在Au(111)表面成功构筑了规则边界形状的单层Mo Se2岛。STM表征揭示了Mo Se2岛Mo边界的高分辨图像。STS谱线显示两种边界在正偏压下有明显不同的电子态信息。通过DFT计算Mo Se2岛的几种边界构型,实验中给出Mo Se2岛两种边界的空间结构(裸露的Se边和单个Se原子饱和的Mo边),并且通过分析两种边界处的投影态密度得到不同的电子态来源于Mo原子的dxz轨道与Se原子的pz轨道耦合。2.二维原子晶体硒化铜的生长、表征及表面修饰。利用一步生长法将Se沉积到贵金属Cu(111)表面,经过后续加热处理实现大面积二维单层蜂窝状贵金属硒化物的生长。随着Se沉积量的变化,硒化铜出现两个不同结构:一维条纹结构和六角周期孔洞结构。STM、LEED和DFT研究揭示了两种结构的内在区别。通过在硒化铜孔洞结构表面沉积原子或分子(Fe,Fe Pc,C60),实现了样品表面不同位置的选择性吸附和填充,进而实现硒化铜表面修饰及功能化。3.二维原子晶体硒化银和二硒化五银的生长和表征。利用一步生长法将Se沉积到贵金属Ag(111)表面,经过后续加热处理实现两种大面积二维单层贵金属硒化物的构筑。两种结构的Se原子沉积量不同,制备温度也不同。其中,单层硒化银具有蜂窝状结构,可以在室温下制备,DFT计算显示其自由单层表面有磁性;制备单层二硒化五银需要沉积更多的Se原子及一定的退火温度,LEED显示其在Ag(111)表面形成(√7×√7)的超结构。4.溴-有机分子氢键网格结构的构筑。本工作中利用分子束外延技术和扫描隧道显微镜表征方法,将非金属原子(Br)和有机分子(DPA,Dc C6PA,PTCDA)沉积到金属表面(Ag(111)和Cu(111)),成功构筑和表征了大面积二维手性网格结构。在网格结构中,Br原子以最大数量氢键(-C-H···Br)的位置周期分布在有机分子之间。DFT计算给出氢键可以稳定这种溴-有机分子网格结构。另外,通过改变有机分子与溴原子的比例,实验上在Ag(111)表面获得了不同氢键网格结构。
[Abstract]:Graphene, a honeycomb structure of carbon atoms, has been widely studied since it was successfully stripped in 2004. Graphene with monatomic thickness has many excellent properties, such as ultra-high carrier mobility, ultra-high transmittance, quantum Hall effect at room temperature, and so on, making it in electronics, optics, magnetism, biomedicine, catalysis, etc. Energy storage and sensors have great application potential and are recognized as "future materials" and "revolutionary materials" in this century. The success of graphene has inspired the exploration of other graphene-like two-dimensional atomic crystal materials, in which two dimensional carbon-group materials (silicene, germane and stannene), non-carbon-group two-dimensional materials (boron, hafnium, black phosphorus, etc.), Transition metal disulfide compounds and hexagonal boron nitride have also made great achievements in their respective fields. In this paper, (STM), low energy electron diffraction (LEED) and density functional theory (DFT) were used to investigate the growth of several novel graphene like two-dimensional atomic crystals, and their structures and electronic properties were characterized. The details are as follows: 1. Boundary structure of monolayer Mo Se2. In this work, the characterization of single layer Mo Se2 island with regular boundary shape on au (111) surface by molecular beam epitaxy (MBE) technique has been reported. The results show that the high resolution image. STS line of Mo Se2 island boundary shows two boundaries under positive bias. There are obviously different electronic state information. Several boundary configurations of Mo Se2 island are calculated by DFT. In the experiment, the spatial structure of two boundaries of Mo Se2 island (bare se edge and single se atom saturated Mo edge) is given. By analyzing the projective density of states at the two boundaries, different electronic states are obtained from the dxz orbits of Mo atoms. Coupling with the pz orbital of se atom. Growth, characterization and Surface Modification of two dimensional Atomic Crystal Copper selenide. Se was deposited on the surface of noble metal Cu (111) by one-step growth method, and the growth of large area two-dimensional honeycomb noble metal selenides was achieved by subsequent heating treatment. With the change of se deposition amount, there are two different structures of copper selenide: one dimensional stripe structure and hexagonal periodic pore structure. STM Led and DFT studies reveal the intrinsic differences between the two structures. The surface modification and functionalization of copper selenide were realized by the deposition of atoms or molecules (Fetife PcC60) on the surface of copper selenide pore structure, and the selective adsorption and filling at different positions on the surface of the sample were realized. Growth and characterization of silver selenide and silver diselenide in two dimensional atomic crystals. Se was deposited on Ag (111) surface of noble metal by one step growth method, and two large area two dimensional monolayer selenides were constructed by subsequent heating treatment. The deposition amount of se atoms in the two structures is different, and the preparation temperature is also different. Among them, silver selenide monolayer has honeycomb structure and can be prepared at room temperature by DFT calculation to show magnetic properties on its free monolayer surface. The preparation of monolayer silver diselenide requires the deposition of more se atoms and a certain annealing temperature to show the superstructure of Ag (111) surface (7 脳 7). Construction of hydrogen bonding network of bromine-organic molecules. In this work, molecular beam epitaxy (MBE) technique and scanning tunneling microscopy (SEM) were used to successfully construct and characterize a large area two-dimensional chiral grid structure by depositing non-metallic atom (Br) and organic molecule (DPA-Dc C6PA-PTCDA) onto metal surface (Ag (111 and Cu (111),). It is shown that the hydrogen bond can stabilize the bromine-organic molecular grid structure in the lattice structure with the maximum number of hydrogen bonds (-C-H Br) distributed periodically between the organic molecules. DFT calculation shows that the hydrogen bond can stabilize the bromine-organic molecular grid structure. In addition, by changing the ratio of organic molecules to bromine atoms, different hydrogen bonding meshes were obtained on Ag (111) surface experimentally.
【学位授予单位】：中国科学院大学(中国科学院物理研究所)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O48
本文编号：2186995
[Abstract]:Graphene, a honeycomb structure of carbon atoms, has been widely studied since it was successfully stripped in 2004. Graphene with monatomic thickness has many excellent properties, such as ultra-high carrier mobility, ultra-high transmittance, quantum Hall effect at room temperature, and so on, making it in electronics, optics, magnetism, biomedicine, catalysis, etc. Energy storage and sensors have great application potential and are recognized as "future materials" and "revolutionary materials" in this century. The success of graphene has inspired the exploration of other graphene-like two-dimensional atomic crystal materials, in which two dimensional carbon-group materials (silicene, germane and stannene), non-carbon-group two-dimensional materials (boron, hafnium, black phosphorus, etc.), Transition metal disulfide compounds and hexagonal boron nitride have also made great achievements in their respective fields. In this paper, (STM), low energy electron diffraction (LEED) and density functional theory (DFT) were used to investigate the growth of several novel graphene like two-dimensional atomic crystals, and their structures and electronic properties were characterized. The details are as follows: 1. Boundary structure of monolayer Mo Se2. In this work, the characterization of single layer Mo Se2 island with regular boundary shape on au (111) surface by molecular beam epitaxy (MBE) technique has been reported. The results show that the high resolution image. STS line of Mo Se2 island boundary shows two boundaries under positive bias. There are obviously different electronic state information. Several boundary configurations of Mo Se2 island are calculated by DFT. In the experiment, the spatial structure of two boundaries of Mo Se2 island (bare se edge and single se atom saturated Mo edge) is given. By analyzing the projective density of states at the two boundaries, different electronic states are obtained from the dxz orbits of Mo atoms. Coupling with the pz orbital of se atom. Growth, characterization and Surface Modification of two dimensional Atomic Crystal Copper selenide. Se was deposited on the surface of noble metal Cu (111) by one-step growth method, and the growth of large area two-dimensional honeycomb noble metal selenides was achieved by subsequent heating treatment. With the change of se deposition amount, there are two different structures of copper selenide: one dimensional stripe structure and hexagonal periodic pore structure. STM Led and DFT studies reveal the intrinsic differences between the two structures. The surface modification and functionalization of copper selenide were realized by the deposition of atoms or molecules (Fetife PcC60) on the surface of copper selenide pore structure, and the selective adsorption and filling at different positions on the surface of the sample were realized. Growth and characterization of silver selenide and silver diselenide in two dimensional atomic crystals. Se was deposited on Ag (111) surface of noble metal by one step growth method, and two large area two dimensional monolayer selenides were constructed by subsequent heating treatment. The deposition amount of se atoms in the two structures is different, and the preparation temperature is also different. Among them, silver selenide monolayer has honeycomb structure and can be prepared at room temperature by DFT calculation to show magnetic properties on its free monolayer surface. The preparation of monolayer silver diselenide requires the deposition of more se atoms and a certain annealing temperature to show the superstructure of Ag (111) surface (7 脳 7). Construction of hydrogen bonding network of bromine-organic molecules. In this work, molecular beam epitaxy (MBE) technique and scanning tunneling microscopy (SEM) were used to successfully construct and characterize a large area two-dimensional chiral grid structure by depositing non-metallic atom (Br) and organic molecule (DPA-Dc C6PA-PTCDA) onto metal surface (Ag (111 and Cu (111),). It is shown that the hydrogen bond can stabilize the bromine-organic molecular grid structure in the lattice structure with the maximum number of hydrogen bonds (-C-H Br) distributed periodically between the organic molecules. DFT calculation shows that the hydrogen bond can stabilize the bromine-organic molecular grid structure. In addition, by changing the ratio of organic molecules to bromine atoms, different hydrogen bonding meshes were obtained on Ag (111) surface experimentally.
【学位授予单位】：中国科学院大学(中国科学院物理研究所)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O48
【相似文献】
相关期刊论文 前4条
1 刘新厚,王风奇,武卫,张建成;原子晶体分析势能函数新理论模型及对硅与锗晶体的应用[J];化学物理学报;1996年04期
2 ;国科大等在二维原子晶体研究中获进展[J];人工晶体学报;2014年06期
3 李林飞;王业亮;高鸿钧;;铪烯:一种基于过渡金属元素的新型二维原子晶体材料[J];物理;2013年12期
4 韩文鹏;史衍猛;李晓莉;罗师强;鲁妍;谭平恒;;石墨烯等二维原子晶体薄片样品的光学衬度计算及其层数表征[J];物理学报;2013年11期
相关会议论文 前3条
1 阚二军;;二维原子晶体中的磁性质[A];中国化学会第28届学术年会第4分会场摘要集[C];2012年
2 林民;彭海琳;刘忠范;;In_2Se_3准二维原子晶体的控制生长与表征[A];中国化学会第28届学术年会第4分会场摘要集[C];2012年
3 孙丽妃;焦丽颖;;TiSe_2二维原子晶体的化学稳定性研究[A];中国化学会第29届学术年会摘要集——第30分会：低维碳材料[C];2014年
相关重要报纸文章 前1条
1 记者 郑晓春;科学家开发出原子晶体管[N];科技日报;2002年
相关博士学位论文 前3条
1 卢建臣;几种新型二维原子晶体材料的构筑及其结构特性[D];中国科学院大学(中国科学院物理研究所);2017年
2 武旭;二维原子晶体锑烯和二硒化铂的制备和物性[D];中国科学院大学(中国科学院物理研究所);2017年
3 裴腾飞;二维原子晶体材料SnSe_x的制备及其器件特性[D];中国科学院大学(中国科学院物理研究所);2017年
，本文编号：2186995
本文链接：https://www.wllwen.com/shoufeilunwen/jckxbs/2186995.html
