共查询到17条相似文献,搜索用时 46 毫秒
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在超高真空系统中制备了C60的Yb填隙化合物薄膜.用x射线光电子能谱研究了Yb和C60结合过程中C 1s,Yb 4f和Yb 4d的变化.利用Yb 4f和C 1s的谱峰强度确定出相纯样品的化学组分接近Yb2.75C60,这一结果与晶体x射线衍射结果一致.Yb 4f和Yb 4d的峰形与峰位表明化合物中Yb的价态为Yb2+.相纯样品(Yb2.75C60)的C
关键词:
60的Yb填隙化合物薄膜')" href="#">C60的Yb填隙化合物薄膜
x射线光电子能谱
Yb价态 相似文献
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在超高真空系统中制备了Yb2.75C60薄膜.对样品进行了同步辐射光电子能谱研究.在费米能级以下约5 eV范围内的谱数据由Yb2.75C60价带(C60分子轨道LUMO,HOMO和HOMO-1导出的能带)和芯态(Yb 4f7/2,4f5/2)能级构成.用紫外能区不同能量的入射光子,用C 2p和Yb 4f光电离截面随光子能量的不同变化规律,通过定量拟合,得到了对谱线有贡献的上述各个组分的峰位、峰宽和强度.结果表明,光子能量高于约30.0 eV时,芯态4f的贡献使得实验结果远远偏离价带的本征态密度分布.因此,研究Yb2.75C60价态时,应使用能量低于30.0 eV的光子.对实验和拟合结果分析,发现了类似纯C60的光电离截面振荡现象.振荡幅度相对于纯C60较小,反映了化合物中C60分子的化学环境对光电离截面振荡现象起着不可忽略的作用. 相似文献
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用紫外光电子能谱和同步辐射光电子能谱研究了Sm掺杂C60薄膜的价带电子结构.Sm的价电子大部分转移给C60,化学键以离子性为主.对于任何化学配比都没有观察到费米边,所以Sm富勒烯超导相在室温下为半导体性质.获得了很接近单相Sm2.75C60的样品在费米能级附近的电子态密度分布.固溶相的光电子发射与Sm2.75C60有明显区别.SmxC60关键词:
60的Sm填隙化合物')" href="#">C60的Sm填隙化合物
价带光电子能谱
电子结构 相似文献
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含铀(U)薄膜在激光惯性约束聚变的实验研究中有重要的用途.研究其在不同气氛下的氧化性能可以为微靶制备、储存及物理实验提供关键的实验数据.通过超高真空磁控溅射技术制备了纯U薄膜及金-铀(Au-U)复合平面膜,将其在大气、高纯氩(Ar)气及超高真空度环境中暴露一段时间后,利用X射线光电子能谱仪结合Ar~+束深度剖析技术考察U层中氧(O)元素分布及价态,分析氧化产物及机理.结果显示,初始状态的U薄膜中未检测到O的存在.Au-U复合薄膜中的微观缺陷减弱了Au防护层的屏蔽效果,使其在3周左右时间内严重氧化,产物为U表面致密的氧化膜及缺陷周围的点状腐蚀物,主要成分均为二氧化铀(UO_2).在高纯Ar气中纯U薄膜仅暴露6 h后表面即被严重氧化,生成厚度不均匀的UO_2.在超高真空度环境下保存12 h后,纯U薄膜表面也发生明显氧化,生成厚度不足1 nm的UO_2.Ar~+束对铀氧化物的刻蚀会因择优溅射效应而使UO_2被还原成非化学计量的UO_(2-x),但这种效应受O含量的影响. 相似文献
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用XPS和AES电子能谱的方法对等离子体辅助分子束外延(MBE)生长的GaN薄膜进行了表面分析和深度剖析.发现红外分子束外延(RFMBE)生长的富镓GaN薄膜实际表面存在O和C吸附层,C主要为物理吸附,而O在GaN表面形成局域化学键产生氧络合物覆盖层,并形成一定的深度分布.杂质O在GaN带隙中导带底形成杂质带同时引入深受主能级,使得带隙变窄室温光吸收谱向低能方向移动,光致发光谱出现宽带发光峰.从而影响GaN薄膜的电学和光学性质
关键词:
GaN薄膜
X射线光电子能谱
俄歇电子能谱
表面分析 相似文献
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This paper reports that the n-type organic thin-fihn transistors have been fabricated by using C60 as the active layer and polystyrene as the dielectric. The properties of insulator and the growth characteristic of C60 film were carefully investigated. By choosing different source/drain electrodes, a device with good performance can be obtained. The highest electron field effect mobility about 1.15 cm2/(V. s) could reach when Barium was introduced as electrodes. Moreover, the C60 transistor shows a negligible 'hysteresis effect' contributed to the hydroxyl-free of insulator. The result suggests that polymer dielectrics are promising in applications among n-type organic transistors. 相似文献
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The changes in core-level electronic structure of In1−xSbx nano-clusters have been studied using X-ray photoelectron spectroscopy. Though, clusters with mean composition InSb show shallow and deep core-level binding energies similar to those of bulk InSb, the Sb and In rich versions show a negative BE shift for the excess element and a positive shift for the minority element. The observed BE shifts have been explained considering a core and surface shell model for the structure of the clusters and possible surface atom core-level shifts. 相似文献
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Photoelectron spectroscopy and X-ray absorption spectroscopy (XAS) measurements have been performed on HfSixOy and HfSixOyNz dielectric layers, which are potential candidates as high-k transistor gate dielectrics. The hafnium silicate layers, 3-4 nm thick, were formed by codepositing HfO2 and SiO2 (50%:50%) by MOCVD at 485 °C on a silicon substrate following an IMEC clean. Annealing the HfSixOy layer in a nitrogen atmosphere at 1000 °C resulted in an increase in the Si4+ chemical shift from 3.5 to 3.9 eV with respect to the Si0 peak. Annealing the hafnium silicate layer in a NH3 atmosphere at 800 °C resulted in the incorporation of 10% nitrogen and the decrease in the chemical shift between the Si4+ and the Si0 to 3.3 eV. The results suggest that the inclusion of nitrogen in the silicate layer restricts the tendency of the HfO2 and the SiO2 to segregate into separate phases during the annealing step. Synchrotron radiation valence band photoemission studies determined that the valence band offsets were of the order of 3 eV. X-ray absorption measurements show that the band gap of these layers is 4.6 eV and that the magnitude of the conduction band offset is as little as 0.5 eV. 相似文献
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The soft X-ray N6,7 (5d to 4f transition) emission spectrum and the X-ray photoemission spectrum of Pt (the latter under two conditions of surface cleanliness) have been obtained, and are compared with the results of photoemission and band theoretical studies. 相似文献
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R.-J. Tarento P. Joyes S. Benlamari R. Lahreche D. E. Mekki 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,43(1-3):237-240
We make a theoretical study of the shake-up of the 1s photoemission of C60. The method takes into account the N-body reactions of the π and σ electrons which appear
during the formation of the photoemission hole on one carbon atom. We analyze the origin of the satellite in the spectra due
to transitions between N-body states. Our calculation shows that the
satellite spectra is essentially given by N-body transitions which involve the creation of one or two electron-hole pairs.
The method has been applied also to C48N12. The situation is more
complex. The spectra of the two most stable species have been investigated. Moreover the influence on the spectra of the position
of the hole created on the carbon atom in C48N12
has been examined (all the carbon positions are not equivalent for some isomers). 相似文献
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An epitaxial ZnO thin film was entirely fabricated by pulsed laser deposition. Both the orientation and the size of the crystallites were studied. The X-ray diffraction (XRD) patterns of the film show strong c-axis oriented crystal structure with preferred (002) orientation. The Phi-scan XRD pattern confirms that the epitaxial ZnO exhibits a single-domain wurtzite structure with hexagonal symmetry. In situ high-temperature XRD studies of ZnO thin film show that the crystallite size increases with increasing temperature, and (002) peaks shift systematically toward lower 2θ values due to the change of lattice parameters. The lattice parameters show linear increase in their values with increasing temperature. 相似文献