Journal of Physics and Chemistry of Solids
The layered ternary ceramics Ti3SiC2 and Ti3AlC2 are isostructural and can form Ti3Si1-xAlxC2 solid solutions combining the advanced properties of both compounds [H.B. Zhang, Y.C. Zhou, Y.W. Bao, M.S. Li, Improving the oxidation resistance of Ti3SiC2 by forming a Ti3Si0.90Al0.1C2 solid solution, Acta Mater. 52 (2004) 3631-3637; E.D. Wu, J.Y. Wang, H.B. Zhang, Y.C. Zhou, K. Sun, Y.J. Xue, Neutron diffraction studies of Ti3Si0.9Al0.1C2 compound, Mater. Lett. 59 (2005) 2715-2719; J.Y. Wang, Y.C. Zhou, First-principles study of equilibrium properties and electronic structure of Ti3Si0.75Al0.25C2 solid solution, J. Phys.: Condens. Matter 15 (2003) 5959-5968; Y.C. Zhou, J.X. Chen, J.Y. Wang, Strengthening of Ti3AlC2 by incorporation of Si to form Ti3Al1-xSixC2 solid solutions, Acta. Mater. 54 (2006) 1317-1322]. In the present work, the solid solutions of Ti3Si1-xAlxC2 (x = 0, 0.25, 0.33, 0.5, 0.67, 0.75, 1) are investigated by first-principle calculations based on pseudo-potential plan-wave method within the density functional theory framework. The results show that as Al content increases in the solid solution, all the bonds have weakened to certain extents, which lead to an unstable structure both energetically and geometrically. The calculated results are compared and discussed with the reported data for the Ti3Si1-xAlxC2 solid solutions. (c) 2007 Elsevier Ltd. All rights reserved.
关键词:
ceramics;ab initio calculations;electronic structure;electrical;conductivity;oxidation behavior;mechanical-properties;ti3sic2;temperature;ti3alc2;air;si
Applied Physics Letters
The Si/Si oxynitride superlattices, with three periods, have been grown using the two-target alternation magnetron sputtering technique. The thicknesses of Si oxynitride layers and Si layers in the superlattices are 2.0 and 1.4 nm, respectively. Visible electroluminescence (EL) from a semitransparent Au film/(Si/Si oxynitride) superlattice/p-Si structure has been observed. Each EL spectrum of the structure has a dominant peak around 640 nm, a weaker peak around 520 nm, and a shoulder around 820 nm. By comparing the EL from the semitransparent Au film/(Si/Si oxynitride) superlattice/p-Si structure with that from a semitransparent Au film/Si oxynitride film/ p-Si structure, we found that the EL efficiency of the former structure is about 2-4 times of that of the latter one. (C) 1998 American Institute of Physics.
关键词:
chemical-vapor-deposition;silicon-nitride films;optical-properties;spectra
Physica Status Solidi a-Applied Research
The interdiffusion of Mo-Si and Ti-Si multilayers is investigated by an in situ X-ray diffraction technique. It is found that the behavior of the interdiffusion in both multilayers is quite different. Both positive and negative interdiffusion take place in Ti-Si multilayers during annealing, while only positive interdiffusion occurs in Mo-Si multilayers. Accompanying interdiffusion, the process of solid state amorphization reaction plays a dominant role in Ti-Si multilayers, on the contrary, the crystallization process was the main process in Mo-Si multilayers. In addition, a transient amorphization process at early stage of annealing is observed in Mo-Si multilayers for the first time.
关键词:
amorphous si;alloy;films;phase
文娇
,
刘畅
,
俞文杰
,
张波
,
薛忠营
,
狄增峰
,
闵嘉华
功能材料与器件学报
利用高分辨率X射线衍射(HRXRD)和拉曼光谱(Raman spectrum)研究了由扩散引起Si/SiGe/Si异质结中Si/SiGe异质界面互混的现象.结果表明:应变弛豫前Si/SiGe异质界面互混程度随热载荷的增加而增强;Si/SiGe异质界面的硼(B)浓度梯度抑制了界面互扩散.总之,Si/SiGe互扩散作用越强诱发Si/SiGe异质界面越粗糙,从而导致器件性能恶化.
关键词:
Si/SiGe互扩散
,
热载荷
,
硼浓度梯度
材料科学技术（英）
By Ar+ sputtering onto Si wafers which were surrounded by Mo plates, uniform cones over a large area on the Si surface were formed. Scanning electron microscopic study showed that the cones were formed on the entire surface of the Si wafer. The dimensions of the uniform cones were one micrometer in diameter and 5similar to6 micrometer's high. They were further characterized by means of cross-sectional transmission electron microscopy, with the technique of micro-diffractions. It was found that the cone contained a pure Si regime and a Mo-rich regime. In the binary Mo-Si zone, we identified three distinct areas vertically: (1) domains of Mo-induced Si ordered structures, (2) a small volume of a new Mo3Si2 structural variant, intergrown with the Si ordered structure, and (3) a small amount of pure Mo nanoparticles covering the surface of the cones. The formation of the large and uniform cones may provide a new surface configuration for potential applications in surface science and technology.
关键词:
Si cones;ordered structure;Mo silicide;copper seed cones;resolution electron-microscopy;surface;growth
X.L.Ma
,
N.G.Shang
,
C.S.Lee
,
S.T.Lee
材料科学技术（英）
By Ar+ sputtering onto Si wafers which were surrounded by Mo plates, uniform cones over a large area on the Si surface were formed. Scanning electron microscopic study showed that the cones were formed on the entire surface of the Si wafer. The dimensions of the uniform cones were one micrometer in diameter and 5~6 micrometers high. They were further characterized by means of cross-sectional transmission electron microscopy, with the technique of micro-diffractions. It was found that the cone contained a pure Si regime and a Mo-rich regime. In the binary Mo-Si zone, we identified three distinct areas vertically: (1) domains of Mo-induced Si ordered structures, (2) a small volume of a new Mo3Si2 structural variant, intergrown with the Si ordered structure, and (3) a small amount of pure Mo nanoparticles covering the surface of the cones. The formation of the large and uniform cones may provide a new surface configuration for potential applications in surface science and technology.
关键词:
Si cones
,
null
,
null
