Structure and growth of titanium buffer layers on Al2O3(0001)

SURFACE SCIENCE

卷:559

Article

Sondergård, E ; Kerjan, O ; Barreteau, C ; Jupille, J

关键词: semi-empirical models and model calculations reflection high-energy electron diffraction (RHEED);    wetting;    epitaxy;    surface thermodynamics (including phase transitions);    aluminum oxide;    silver;    titanium;   

DOI  :  10.1016/j.susc.2004.03.072

来源: Elsevier

【 摘 要 】

The structure of titanium films on alpha-Al2O3(0001) surfaces at room temperature was investigated through in situ reflection high energy electron diffraction (RHEED). The alpha-phase of titanium was observed to grow with the Ti(0001)parallel toAl(2)O(3)(0001), Ti[1100]parallel toAl(2)O(3)[2110] and Ti[1010]parallel toAl(2)O(3)[1100] epitaxy. For up to 6 nm thick films, an other structure was found to co-exist with alpha-Ti. Its presence has dramatic consequences for the wetting of silver, which partly explains the non-trivial buffer effect of titanium at the silver/alumina interface. From the RHEED data, the extra structure is assigned to the high-pressure hexagonal omega-Ti phase. This is supported by tight-binding total energy calculations that demonstrate that the omega phase could actually be stabilized by the alpha-Al2O3(0001) substrate. (C) 2004 Elsevier B.V. All rights reserved.

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