ABSTRACT
We report a study of the surface temperature (T(s)) dependence of Cu(2)O formation on a Cu(110) surface induced by a hyperthermal O(2) molecular beam (HOMB), using x-ray photoemission spectroscopy in conjunction with synchrotron radiation. From the T(s) dependence of the O uptake curves, the direct dissociative adsorption process mainly contributes to the formation of the p(2 × 1)-O structure with an O coverage (Θ) of 0.5 ML for 2.2 eV HOMB incidence. On the other hand, the rate of oxidation at Θ > 0.5 ML, particularly in Cu(2)O formation, strongly depends on the T(s). Thicker Cu(2)O islands were found inhomogeneously at 400 and 500 K, suggesting the dominant role of the migration of Cu atoms in the Cu(2)O formations on the Cu(110) surface.
ABSTRACT
We report the present performance of a grating monochromator at the newly constructed soft x-ray beamline (BL23SU at the SPring-8), which can measure both silicon and oxygen K-edges. That provides new opportunities for XAFS measurements of solids up to 2100 eV.
ABSTRACT
An ultrahigh-vacuum reaction apparatus to study synchrotron-radiation-stimulated processes has been constructed and placed on beamline 4B of the synchrotron radiation storage ring (UVSOR) at the Institute for Molecular Science. The apparatus is designed so that multiple synchrotron radiation processes such as etching and chemical vapour deposition can be carried out successively without breaking the high vacuum. It is equipped with IR reflection absorption spectroscopy (IRRAS) apparatus and reflective high-energy electron diffraction (RHEED) apparatus for in situ observations. The basic parameters of the apparatus including etching and deposition rates have been measured. IRRAS using buried metal layer substrates has been confirmed to be a very useful method of analyzing the reaction mechanisms of the synchrotron-radiation-stimulated processes.
ABSTRACT
The sensitivity and linearity of infrared reflection absorption spectroscopy (IRAS) has been significantly improved by using a buried-metal-layer (BML) substrate having an SiO(2)(15 nm)/Al(200 nm)/Si(100) structure, instead of a plain Si(100) substrate. By applying this BML-IRAS technique to the in situ observation of synchrotron-radiation-induced chemical vapor deposition of amorphous Si (a-Si) on an SiO(2) surface using Si(2)H(6) gas, the vibrational spectra of surface SiH(n) species in this reaction system have been observed for the first time with sufficient sensitivity for submonolayer coverage. The main silicon hydride species after deposition at 423 K are surface SiH(2) and SiH. Surface SiH(3) and SiH(2) are observed to be easily decomposed by synchrotron radiation irradiation. The decomposition rate of SiH by synchrotron radiation irradiation is much slower than those of SiH(2) and SiH(3).
