Lj. Richter et al., ADSORPTION AND PHOTODECOMPOSITION OF MO(CO)(6) ON SI(111) 7X7 - AN INFRARED REFLECTION-ABSORPTION SPECTROSCOPY STUDY, The Journal of chemical physics, 100(4), 1994, pp. 3187-3200
The adsorption and photodecomposition of Mo(CO)(6) adsorbed on Si(111)
7X7 surfaces has been studied with Auger electron spectroscopy, tempe
rature programmed desorption, low energy electron diffraction and infr
ared reflection absorption spectroscopy in a single external reflectio
n configuration. The external-reflection technique is demonstrated to
have adequate sensitivity to characterize submonolayer coverages of ph
otogenerated Mo(CO)(x) fragments. It is proposed that the first layer
of Mo(CO)(6) adsorbs in ordered islands with a Mo(CO)(6) atop each ada
tom of the 7X7 reconstructed Si surface. UV irradiation of these islan
ds produces a carbonyl fragment, identified as chemisorbed Mo(CO)(5).
The Mo(CO)(5) thermally decarbonylates via two subcarbonyl intermediat
es with little CO dissociation. Photolysis of thicker layers results i
n the formation of Mo-x(CO)(y) dimers/polymers, as evidenced by the ap
pearance of bridging CO, which is attributed to a facile association r
eaction. The dimer/polymer species correlate with deposition of C and
O on the surface.