Subsurface miscibility of metal overlayers with V, Nb and Ta substrates

Hüger, E. and Wormeester, H. and Osuch, K. (2005) Subsurface miscibility of metal overlayers with V, Nb and Ta substrates. Surface Science, 580 (1-3). pp. 173-194. ISSN 0039-6028

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Abstract:	The high solubility and diffusivity of oxygen in Nb, Ta and V are responsible for the difficulty in the preparation of a clean, well-ordered (1 0 0) surfaces of these early transition metals. The deposition and subsequent annealing of a metal overlayer on Nb(1 0 0) are a convenient route for the preparation of flat surfaces with the Nb lattice constant and a metallic character. Such well-ordered, stable, inert and easily reproducible Nb(1 0 0)-like surfaces can be produced due to the suppression of oxygen surface segregation by a suitable layer blocking sub-surface oxygen diffusion. For example, a Nb(1 0 0)-like surface can be obtained by annealing thin Au or Pd films deposited on Nb(1 0 0), since this results in a Au–Nb or Pd–Nb alloy situated just below the surface which preserves the structure of the Nb-lattice and effectively suppresses the oxygen segregation toward the surface. In contrast, Ag and Cu layers do not show this property as these metals do not form a bulk alloy with Nb. The presence or absence of bulk alloying and its relation to surface oxygen contamination is a general phenomena observed for many metallic layers deposited on V, Nb and Ta substrates. A discussion of results reported in the literature is given for these adsorbate systems.
Item Type:	Article
Copyright:	© 2005 Elsevier
Faculty:	Science and Technology (TNW)
Research Group:	Physics of Interfaces and Nanomaterials (PIN)
Link to this item:	http://purl.utwente.nl/publications/77400
Official URL:	http://dx.doi.org/10.1016/j.susc.2005.01.055
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