Growth and electronic structure of Nb and Ta films on Pd and their interaction with CO

Journal Article · Mon May 01 04:00:00 EDT 1989 · J. Vac. Sci. Technol., A; (United States)

DOI:https://doi.org/10.1116/1.576005· OSTI ID:6295119

Jiang, L Q; Ruckman, M W; Strongin, M

The growth of Nb and Ta films on Pd(111) and their modification of CO chemisorption are studied using ultraviolet photoelectron spectroscopy (UPS), low-energy electron diffraction, and low-energy ion scattering (LEIS). At 300 K, LEIS shows significant amounts of Pd in the top layer even after more than a monolayer of Nb or Ta is deposited. This is in contrast to Pd on Nb or Ta(110) where a Pd monolayer completely covers the substrate. UPS shows that the surface electronic structure at monolayer Nb or Ta coverage resembles that of a Pd monolayer on Nb or Ta(110) and is characterized by strong Pd 4d emission 1--4 eV below E/sub f/ and a low density of states at E/sub f/. Molecular CO adsorption is observed at submonolayer coverage; there is little CO adsorption at monolayer coverage and dissociative CO adsorption starts at greater than monolayer coverage. It is concluded that the deposited Nb or Ta monolayers intermix with the Pd(111) substrate and it is also shown that this behavior can be understood by examining the energetics of the system.

• Research Organization: Physics Department, Brookhaven National Laboratory, Upton, New York 11973-6000 and Queens College of the City University of New York, Flushing, New York 11367-0904
• OSTI ID: 6295119
• Journal Information: J. Vac. Sci. Technol., A; (United States), Journal Name: J. Vac. Sci. Technol., A; (United States) Vol. 7:3; ISSN JVTAD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
360104 -- Metals & Alloys-- Physical Properties
CHEMICAL REACTIONS
CHEMISORPTION
COATINGS
COHERENT SCATTERING
CRYSTAL GROWTH
DATA
DEPOSITION
DIFFRACTION
ELECTRON DIFFRACTION
ELECTRON EMISSION
ELECTRONIC STRUCTURE
ELEMENTS
EMISSION
EXPERIMENTAL DATA
FILMS
INFORMATION
ION SPECTROSCOPY
METALS
NIOBIUM
NUMERICAL DATA
PALLADIUM
PLATINUM METALS
SCATTERING
SEPARATION PROCESSES
SORPTION
SPECTROSCOPY
SURFACE PROPERTIES
TANTALUM
TRANSITION ELEMENTS
ULTRAHIGH VACUUM