Epitaxy and growth of titanium buffer layers on
نویسنده
چکیده
The structure and growth of thin films of titanium on α−Al2O3 at room temperature were investigated though in situ RHEED observations. Two different structures coexists at low coverage. One corresponds to the Ti(0001) ‖ Al2O3(0001), Ti[1100] ‖ Al2O3[2110] and Ti[1010] ‖ Al2O3[1100] epitaxy of the α phase of titanium reported before for thick films prepared at high temperature. The other structure can be explained by co-existence of α and ω Ti in thin films. It was shown, with the use of tight-binding total energetic calculations that, the ω phase could actually be stabilized by the substrate. In addition, it was demonstrated that the presence of this extra structure has a dramatic effect on the epitaxial growth of the Ag overlayers on the system. This can be the origin of the non-trivial buffer effect of titanium previously observed.
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