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Chemical state analysis of carbon alloys using soft x-ray synchrotron radiation

使用软 X 射线同步辐射分析碳合金的化学状态

基本信息

批准号：
15550081
负责人：
YASUJI Muramatsu
金额：
$ 1.86万
依托单位：
Japan Atomic Energy Research Institute
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

For the development of advanced functional carbon materials, it is important to understand the origin of their functions from the view point of electronic/molecular structures. We have therefore investigated their electronic structure and chemical-state using soft x-ray synchrotron radiation. In this study, we have achieved (1) the data base formation of x-ray spectra of various fundamental carbon compounds as basic research, and (2) chemical-state analysis of various industrial carbon materials as applied research.(1) Soft x-ray database :Soft x-ray emission spectra of various polycyclic aromatic hydrocarbons (PAH) were measured using synchrotron radiation. From their spectral features, the new relation between the peak features and the molecular size. This indicates that nano-size or hydrogenation ratio of nano-graphite can be easily estimated from the soft x-ray emission spectra. This can therefore be proposed as a new method to evaluate the nano-size of nano-graphitic carbon materi … More als.(2) Chemical state analysis of industrial carbon materials :Carbon films on the Japanese smoked roof the "Ibushi-Kawara" were characterized by high-resolution soft X-ray spectroscopy using synchrotron radiation. By comparing the soft x-ray emission and absorption spectra of Kawara with the reference carbon compounds, it was determined that the carbon films on Kawara consist of mostly carbon-black-like sp_2 carbon atoms and that the surface also contains polyethylene-like sp_3 carbon atoms. The take-off/incident-angle dependence on the x-ray emission/absorption spectra of Kawara shows that the carbon-black-like sp_2 carbon atoms partially form a layer structure oriented parallel to the basal clay plane, and that the degree of orientation of the carbon films is estimated to be 50% that of highly oriented pyrolytic graphite (HOPG). The microstructure of the carbon films on Kawara is one in which half of the carbon-black-like sp_2 carbon atoms form layer-structured clusters parallel to the basal clay plane and the rest of the carbon atoms form random-structured clusters which rigidly connect the layer-structured clustersSoft x-ray emission spectra in the BK and CK regions of Ru/B_4C multilayers under the x-ray standing-wave conditions, aiming at nondestructive chemical-bonding-state analysis of the interlayers. The Ru/B_4C multilayer samples were selectively excited by the monochromatized undulator radiation with on the Bragg reflection condition around 360 eV and off- conditions which were sufficiently higher energy to BK and CK thresholds. Spectral feature differences excited between on-Bragg-reflection-condition and on the off-conditions were symmetrically changed against the excitation energy around the Bragg reflection condition. This symmetrical spectral feature should indicate the chemical-bonding-state difference between the interlayers and bulk layers in the Ru/B_4C multilayers.The electronic structure transition between the semiconducting and metallic states in boron (B)-doped diamonds was element-selectively observed by soft x-ray emission and absorption spectroscopy using synchrotron radiation. For lightly B-doped diamonds, the B2p-density of states (DOS) in the valence band were enhanced with a steep-edge-feature near the Fermi level, and localized acceptor levels, which is characteristic of semiconductors, were clearly observed both in B2p- and C2p-DOS in the conduction bands. For heavily B-doped diamonds, the localized acceptor levels developed into extended energy levels and the new energy levels generated formed an extended conduction band structure that overlapped with the valence band. Thus, the metallic energy band structure is actually formed by heavy boron doping. These valence and conduction band structures observed by soft x-ray emission and absorption spectroscopy accounted for the electrical properties of B-doped diamonds. Less

为了开发先进的功能性碳材料，从电子/分子结构的角度理解其功能的起源是重要的。因此，我们研究了它们的电子结构和化学状态，使用软x射线同步辐射。在本研究中，我们实现了（1）作为基础研究的各种基本碳化合物的X射线光谱数据库的形成，以及（2）作为应用研究的各种工业碳材料的化学状态分析。(1)软X射线数据库：使用同步辐射测量各种多环芳烃（PAH）的软X射线发射光谱。从它们的光谱特征出发，提出了峰特征与分子大小之间的新关系.这表明，纳米石墨的纳米尺寸或氢化率可以很容易地从软X射线发射光谱估计。这为评价纳米石墨碳材料的纳米尺寸提供了一种新的方法 ...更多信息人症(2)工业碳材料的化学状态分析：使用同步辐射的高分辨率软X射线光谱对日本熏屋顶“Ibushi-Kawara”上的碳膜进行了表征。通过比较Kawara和参比碳化合物的软X射线发射光谱和吸收光谱，确定Kawara上的碳膜主要由类炭黑的sp_2碳原子组成，表面还含有类聚乙烯的sp_3碳原子。Kawara的X射线发射/吸收谱与发射/入射角的关系表明，类炭黑sp_2碳原子部分形成平行于粘土基面的层状结构，碳膜的取向度约为高取向热解石墨（HOPG）的50%。Kawara表面碳膜的微观结构是，一半的类炭黑sp_2碳原子形成平行于粘土基面的层状结构团簇，其余的碳原子形成刚性连接层状结构团簇的无规结构团簇。目的是对夹层的化学键合状态进行无损分析。Ru/B_4C多层膜样品被单色化的波荡器辐射选择性地激发，其布拉格反射条件在360 eV左右，而非布拉格反射条件足够高到BK和CK阈值。在布拉格反射条件下和在关断条件下激发的光谱特征差异相对于布拉格反射条件附近的激发能量对称地变化。用同步辐射软X射线发射和吸收光谱对Ru/B_4C多层膜的半导体态和金属态之间的电子结构转变进行了元素选择性观察。对于轻B掺杂的金刚石，在价带中的B2 p态密度（DOS）被增强，在费米能级附近具有陡峭的边缘特征，并且在导带中的B2 p和C2 p-DOS中清楚地观察到局部受主能级，这是半导体的特征。对于重掺B的金刚石，局域受主能级发展成扩展能级，并且产生的新能级形成与价带重叠的扩展导带结构。因此，金属能带结构实际上是通过重硼掺杂形成的。这些观察到的软X射线发射和吸收光谱的价带和导带结构占B掺杂的金刚石的电性能。少

项目成果

期刊论文数量（24）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

放射光軟X線線状態分析の研究・技術動向

同步加速器软X射线状态分析研究及技术动态

DOI：
发表时间：
2005
期刊：
X線分析の進歩 36
影响因子：
0
作者：
村松康司
通讯作者：
村松康司

標準的な固体炭素化合物の軟X線発光・吸収スペクトル

标准固体碳化合物的软X射线发射和吸收光谱

DOI：
发表时间：
2004
期刊：
X線分析の進歩 35
影响因子：
0
作者：
村松康司;村松康司 et al.
通讯作者：
村松康司 et al.

Soft x-ray absorption spectra of amorphous carbon

无定形碳的软X射线吸收光谱

DOI：
发表时间：
期刊：
Physica Scripta (in press)
影响因子：
0
作者：
村松康司;村松康司 et al.;Y.Muramatsu et al.;Y.Muramatsu et al.;Y.Muramatsu et al.;Y.Muramatsu et al.
通讯作者：
Y.Muramatsu et al.

Soft X-Ray Emission and Absorption Spectra of Typical Solid Carbon Compounds

典型固体碳化合物的软 X 射线发射和吸收光谱