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Synthesis of metal encapsulated Si clusters and its application to formation of interfacial nanostructures

金属封装硅团簇的合成及其在界面纳米结构形成中的应用

基本信息

批准号：
16201026
负责人：
KANAYAMA Toshihiko
金额：
$ 30.78万
依托单位：
National Institute of Advanced Industrial Science and Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

The objective of this research project is to investigate the possibility of a cage cluster composed of 12 Si atoms encapsulating a transition metal atom M, MSi_<12> as a building block of nanostructures on surfaces or interfaces of Si. We obtained the following achievements.1. We have developed a multi-pole ion trap for synthesis of clusters with a specific atomic composition. This trap consists of 36 pole electrodes arranged in a square lattice surrounded by a cage electrode, and has the ability to confine ions with a wide range of mass values and extract efficiently ions having a mass larger than a specific value.2. Our ab-initio calculations demonstrated that the structural stability of the MSi_<12> cluster originates in the efficient covalent bonding of the central M atom with the surrounding Si atoms accompanied with charge transfer.3. It has been shown by scanning tunneling microscopy and X-ray photoelectron spectroscopy that the reaction of SiH_4 molecules with Mo atoms deposite … More d on Si (111)7x7 surfaces yields MoSi_n clusters with a semiconducting band gap.4. We predict by first principles calculations that an atomically-thin layered compound, (MoSi_<12>)_n is a semiconductor with the energy band gap larger than 0.5 eV. This material is composed of a layer of Mo atoms sandwiched by two layers of Si atoms, and is characterized by the fact that the electronic structure can be tuned by replacing the Mo atoms with other transition metals.5. The charge transfer doping has been demonstrated for carbon-nanotube transistors and Si surfaces. This doping method utilizes the principle that the charge transfer is induced and electrons or holes are generated when solid surfaces are deposited with clusters or molecules having a sufficiently low ionization potential or a large electron affinity. We actually demonstrated the hole carrier generation using such clusters as TaF_6 and C_<60>F_<36> and analyzed the relation between the induced charge density and the energy levels of clusters. Less

本研究的目的是研究由12个Si原子组成的笼状团簇包封过渡金属原子M，MSi<12>作为Si表面或界面上纳米结构的构建块的可能性。我们获得了以下成果。1.我们已经开发了一个多极离子阱合成具有特定原子组成的团簇。该阱由36个极电极组成，以笼形电极包围的正方形网格排列，具有约束宽范围质量值离子和有效提取质量大于特定值离子的能力.我们的从头计算结果表明，MSi_团簇的结构稳定性<12>源于中心M原子与周围Si原子之间的有效共价键合，并伴随着电荷转移.用扫描隧道显微镜和X射线光电子能谱研究了SiH_4分子与Mo原子的反应，发现SiH_4分子与Mo原子的反应生成了SiH_4-Mo复合物。 ...更多信息 d在Si（111）7 x7表面上的生长得到了具有半导体带隙的MoSi_n团簇.通过第一性原理计算，我们预测原子级薄层化合物（MoSi<12>）n是一种半导体，其能带隙大于0.5eV。这种材料由一层Mo原子和两层Si原子组成，其特点是可以通过用其他过渡金属取代Mo原子来调节电子结构。5.碳纳米管晶体管和硅表面的电荷转移掺杂已被证明。这种掺杂方法利用了这样的原理，即当固体表面沉积有具有足够低的电离电势或大的电子亲和力的簇或分子时，诱导电荷转移并产生电子或空穴。我们实际演示了TaF_6和C_ F_2等团簇的空穴载流子产生<60>，并<36>分析了诱导电荷密度与团簇能级的关系。少