The K-shell near-edge X-ray absorption fine structure spectra of solid CbO and Ciu have been recorded with high spectral resolution. The spectra exhibit sharp resonances associated with transitions to unfilled P* molecular orbitals and, at higher energy, broader resonances associated with cJ*-like orbitals. The observed energy splitting of the x* resonances can be accounted for by published extended Hiickel calculations. Our data clearly reveal that the fullerene films resemble molecular solids with considerably stronger intra-molecular than inter-molecular interactions.

Articles you may be interested inDetermination of bonding structure of Si, Ge, and N incorporated amorphous carbon films by near-edge x-ray absorption fine structure and ultraviolet Raman spectroscopy

It is shown that LiF(100) films with the electronic properties of cleaved bulk LiF crystals can be grown epitaxially on Ge(100). These include an exceptionally large, negative electron affinity of −2.7 eV, which leads to intense photoemission at zero kinetic energy. The valence band offset ranges from 7.3–7.6 eV.

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The chemisorption and reaction of dichlorosilane (SiH2Cl2) with Si(111) and Si(100) surfaces is investigated with core-level soft x-ray photoelectron spectroscopy employing synchrotron radiation, in order to ascertain the surface chemistry involved in atomic layer epitaxy (ALE). Exposures to 8 kL of SiH2Cl2 were performed as a function of sample temperature in the range from room temperature to 800 °C. At all temperatures, SiH2Cl2 chemisorbs dissociatively forming silicon monochloride surface species. The coverage of monochloride displays a maximum for exposures at ∼600 °C. Under all conditions studied, larger chlorine coverages are observed on Si(100) than on Si(111). A Si surface that was first saturated with SiH2Cl2 at 600 °C was subsequently exposed to H2 at 600 °C, and no reaction occurred. These results indicate that recent models for silicon ALE are incorrect. An alternative method for low-temperature ALE of Si is proposed, in which SiH2Cl2 is adsorbed onto Si at 600 °C and Cl is removed via reaction with atomic H.