Adsorption and growth modes of Bi on Pt(111)

Journal Article · Sat Nov 15 00:00:00 EST 1986 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.451484· OSTI ID:5228777

Paffett, M T; Campbell, C T; Taylor, T N

The vapor deposition of Bi on Pt(111) at 110 and --600 K have been characterized by Auger electron spectroscopy (AES), thermal desorption mass spectroscopy (TDMS), low-energy electron diffraction (LEED), and changes in the work function (..delta..phi). At 110 K Bi growth follows a layer-by-layer mechanism. At --600 K Bi fills the first monolayer (theta/sub Bi/approx. =0.56) relatively uniformly, followed by 3D island growth. Bi desorption is characterized by a large, coverage-dependent desorption energy, E/sub des/ = (81-34.2 theta/sub Bi/ ) kcal mol/sup -1/, in the first monolayer, and zero-order kinetics with constant activation energy (E/sub des/ = 53--56 kcal mol/sup -1/) for the multilayer. Many LEED patterns are observed within the first monolayer for both cold and hot substrates. Structural models for these are proposed which are consistent with coverages obtained by AES. Annealed structures show continuous compression of hexagonal Bi overlayers with increasing coverage, subject to mild substrate constraints. At 110 K and theta/sub Bi/ >0.33, uniaxial compression is instead seen, due to an unsurmounted energy barrier. Weakly repulsive lateral Bi--Bi interactions (due to dipole repulsions) dominate submonolayer growth. These results for the semimetal Bi are intermediate in behavior between alkali and transition metal overlayers on Pt(111). This is consistent with the relative strengths of the surface dipole of these adsorbed metals.

• Research Organization: Electronics and Chemistry Divisions, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
• OSTI ID: 5228777
• Journal Information: J. Chem. Phys.; (United States), Vol. 85:10
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BISMUTH
ADSORPTION
CHEMICAL VAPOR DEPOSITION
PLATINUM
SORPTIVE PROPERTIES
AUGER ELECTRON SPECTROSCOPY
ELECTRON DIFFRACTION
MASS SPECTROSCOPY
SUBSTRATES
SURFACE PROPERTIES
WORK FUNCTIONS
CHEMICAL COATING
COHERENT SCATTERING
DEPOSITION
DIFFRACTION
ELECTRON SPECTROSCOPY
ELEMENTS
FUNCTIONS
METALS
PLATINUM METALS
SCATTERING
SORPTION
SPECTROSCOPY
SURFACE COATING
TRANSITION ELEMENTS
400201* - Chemical & Physicochemical Properties