Electron spectroscopy study of the Cu/SrTiO3(100)\mathrm{Cu/SrTiO_3(100)} interface

Interface formation of copper on both reduced and stoichiometric SrTiO 3(100) was investigated using photoemission (XPS, UPS), electron diffraction (LEED) and electron energy loss spectroscopy (HREELS). The growth mode of Cu on both surfaces involves the formation of a 2D-like layer and islands, but the thickness of the 2D-like layer and the number of islands is higher on the reduced substrate due to the higher number of defects. An analysis of the Auger parameter of Cu during growth demonstrates the strong interaction of Cu with SrTiO 3. HREELS experiments showed a strong influence of the impact scattering interaction from the changes in the spectra with coverage, and the importance of the two different terminations of the (100) surface

Copper/oxide interface formation: a vibrational and electronic investigation by electron spectroscopies

In this study, we deposited copper on a MgO(100) surface at room temperature (using a Knudsen cell) and studied the interface formation using electron spectroscopy. The evolution of the AES peak intensities showed that copper grows on MgO(100) in the Stranski-Krastanov mode. In HREELS experiments, the intensity and the position of the energy loss corresponding to the MgO surface optical phonon at 80.7 meV, both decrease with increasing Cu coverage. These results agree with theoretical spectra simulated from the dielectric theory by considering a Cu2O overlayer on a semi-infinite MgO crystal substrate at the beginning of the growth. From the HREELS data, both the formation of a homogeneous Cu metallic overlayer or a CuO overlayer on MgO can be ruled out. The synchrotron-radiation (SR) photoemission measurements were performed in the vicinity of the Cu3p3d resonance. The positions of the Cu resonance peaks as a function of Cu coverage on MgO show that at low coverage the difference in energy between the main Cu 3d peak and the resonance peak is close to that found in Cu2O and at higher coverage close to metallic copper indicating the formation of an interacting phase at the beginning followed by the growth of metallic copper

Photoemission study of the Al-Sb(111) interface

We have studied the interface formation between Sb(111) surfaces and evaporated aluminum with photo emission using synchrotron radiation. Energy distribution curves were measured from the Al 2p and Sb 4d core levels and from the valence band. A curve-fitting procedure was applied to the core-level spectra in order to decompose the peaks into individual components. A model calculation was performed to explain the intensity variation of the different Al 2p components. We show that a two-dimensional layer of AlSb is formed and that Al clusters grow on top of AlSb as soon as a fraction of a mono layer of AlSb is present. This also explains the behavior of the Sb 4d integrated peak areas and of the valence-band energy distribution curves. Finally, partial-yield spectra have been measured in order to assess the AlSb formation and to study the Al 2p exciton

Tribological and structural properties of amorphous B-N-C coatings

Amorphous BxNyCz:H films were prepared in a capacitively coupled r.f. PACVD reactor at deposition temperatures 0.5). As an exception, a striking similarity is found between a-B:H and a-C:H films with respect to their mechanical properties (hardness, Young's modulus). Nevertheless, these a-B:H films also show a much lower wear resistance in a ball-on-disc test due to different friction mechanisms related to the formation of transfer layers. These results are correlated with the microstructural properties of the coatings as determined from infrared spectroscopy and Raman spectroscopy

Resonant Interaction of Low Energy Electrons with lntramolecular Vibrations in Solid C60

The energy-dependant cross sections of the impact-excited intramolecular vibrations in an epitaxial C60(111) film have been measured by High Resolution Electron Energy Loss Spectroscopy (HREELS). A Negative Ion Resonance (NIR) behaviour is evidenced by a dramatic cross-section enhancement at a primary energy of ~2.9 eV together with some fine structures on the high energy side. Through comparison with experimental results on the unoccupied states and on the electronic excitations of solid C60, these NIR structures can be correlated to a temporary trapping of the probing electron in the LUMO+3-derived state in the framework of an 'electronic excitation associated' NIR process.

Development of an all-solid-state pulsed picosecond laser system for nonlinear spectroscopy

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