The stability of ultrathin metal films on W(110) and W(111)

• Published in: Surface science Vol. 247; no. 2; pp. 175 - 187
• Main Authors: Madey, Theodore E, Song, Ker-Jar, Dong, Cheng-Zhi, Demmin, Richard A
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 01.05.1991; Amsterdam Elsevier Science; New York, NY
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Metals. Metallurgy; Physics; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/0039-6028(91)90124-B

Ultrathin films of platinum on tungsten display a rich variety of phenomena related to epitaxial growth. Pt grows on W(110) in a layer-by-layer mode at 300 K; upon annealing multilayers of Pt to T > 800 K, clusters of three-dimensional crystallites form on top of a pseudo-morphic Pt monolayer. When oxygen is present on the surface, the Pt monolayer is no longer stable. Annealing coadsorbed Pt and O on W(110) causes nearly all the Pt to agglomerate into clusters as the oxygen largely replaces the monolayer on the surface. Annealing Pt on W(111) in the range 800 < T < 1500 K leads to a different behavior: microscopic facets of W having {211} orientation are formed. The faceting appears to be driven by a Pt enhanced anisotropy in the surface free energy. Results based on LEED, Auger, and scanning tunneling microscopy (STM) are presented.