Adsorption and photodecomposition of Mo(CO)[sub 6] on Si(111) 7[times]7: An infrared reflection absorption spectroscopy study

Journal Article · Tue Feb 15 04:00:00 EST 1994 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.466410· OSTI ID:5343570

Richter, L J; Buntin, S A; Chu, P M; Cavanagh, R R ^[1]

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1. Surface and Microanalysis Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

The adsorption and photodecomposition of Mo(CO)[sub 6] adsorbed on Si(111) 7[times]7 surfaces has been studied with Auger electron spectroscopy, temperature programmed desorption, low energy electron diffraction and infrared reflection absorption spectroscopy in a single external reflection configuration. The external-reflection technique is demonstrated to have adequate sensitivity to characterize submonolayer coverages of photogenerated Mo(CO)[sub [ital x]] fragments. It is proposed that the first layer of Mo(CO)[sub 6] adsorbs in ordered islands with a Mo(CO)[sub 6] atop each adatom of the 7[times]7 reconstructed Si surface. UV irradiation of these islands produces a carbonyl fragment, identified as chemisorbed Mo(CO)[sub 5]. The Mo(CO)[sub 5] thermally decarbonylates via two subcarbonyl intermediates with little CO dissociation. Photolysis of thicker layers results in the formation of Mo[sub [ital x]](CO)[sub [ital y]] dimers/polymers, as evidenced by the appearance of bridging CO, which is attributed to a facile association reaction. The dimer/polymer species correlate with deposition of C and O on the surface.

• DOE Contract Number: AI05-84ER13150
• OSTI ID: 5343570
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 100:4; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
ABSORPTION SPECTROSCOPY
ADSORPTION
AUGER ELECTRON SPECTROSCOPY
CARBONYLS
CHEMICAL REACTIONS
COHERENT SCATTERING
DECOMPOSITION
DESORPTION
DIFFRACTION
ELECTROMAGNETIC RADIATION
ELECTRON DIFFRACTION
ELECTRON SPECTROSCOPY
ELEMENTS
INFRARED SPECTRA
MOLYBDENUM COMPOUNDS
PHOTOCHEMICAL REACTIONS
RADIATIONS
REFRACTORY METAL COMPOUNDS
SCATTERING
SEMIMETALS
SILICON
SORPTION
SORPTIVE PROPERTIES
SPECTRA
SPECTROSCOPY
SURFACE PROPERTIES
TRANSITION ELEMENT COMPOUNDS
ULTRAVIOLET RADIATION