A 180° deflection toroidal analyzer is developed for a simultaneous angle and energy analysis of the electron discharged from the solid surface. The measurements in angle-resolved photo- and Auger electron spectroscopy in a short time are possible with this analyzer. In present research, we designed the optimum input-lens-system for improvement of focusing properties and estimated it by experimental comparison with the former designed one. According to the FWHM diagram of the energy distribution of electron elastically scattered from Ag(111) surfaces, the optimum lens system has smaller aberration for retarding ratio with wide range of 2-30. In addition, it turned out that the deflection field in lens system compensated for the fringe field and optimized the trajectories in the analyzer, and these results were in good agreement with those obtained by trajectory simulation. Moreover, under the experiment condition based on the above-mentioned examination, we measured the two-dimensional pattern of O KLL Auger electron diffraction from MgO(001) surface.
We have investigated the chemical bonding states at the surfaces of La1.5Ba0.5SrCu2O6-d annealed under CO, CO2 and SO2 gaseous conditions, by using X-ray photoelectron spectroscopy (XPS). The C 1s and S 2p core-level data obtained from XPS indicate that each adsorbate exists as CO3δ- and SO4δ- on the reaction surfaces, respectively. The Cu 2p XPS spectra suggest that the reaction surfaces of the cuprate donate the electrons to the adsorbates and that the hybridizations of Cu(3d)-O(2p) orbitals change.
Thin films of PbTiO3 (PT) were epitaxially grown on miscut (001)SrTiO3 (ST) substrates with various partial oxygen pressures during the sputtering deposition. Under a low partial oxygen pressure (Ar/O2≥20/5) the film growth was governed by a step-flow resulting in a continuous structure with a flat surface. Under a higher partial oxygen pressure (Ar/O2≤20/6) the sputtered films showed island structures with micro-pinholes. It is considered that the excess oxygen will reduce the surface mobility of adatoms which induces the island growth. XRD analyses showed that the increase of partial oxygen pressure increased the full width at half maximum intensity of the PT thin films, although these sputtered films showed a single crystal of PT with (001) orientation. The partial oxygen pressure is essential for the control of microstructure.
We have observed single isolated faulted-half (F) of DAS structure in unreconstructed regions of Si(111) remained after rapid quenching to 380°C, by using scanning tunneling microscopy. We have observed even-sized F of 6×6, 8×8, 10×10 and 12×12 during the size-changes of odd-sized F. The odd-sized F appearing in the size-changes is always irregular-type. We proposed structural models of the even-sized and irregular odd-sized F. As a whole, we observed the size-changes of single F: irregular 5×5-F↔6×6-F↔ irregular 7×7-F↔8×8-F↔irregular 9×9-F↔10×10-F↔irregular 11×11-F↔12×12-F↔irregular 13×13-F . From these results, we proposed the mechanism of DAS domain formation.
“Electron-doped”; (Nd, Ce)2CuO4 (NCCO) superconductor thin films were prepared by post-annealing of metallic double-layer films of Nd(Ce) and Cu deposited onto (001) surface of SrTiO3 (STO) substrates in air at 600 to 1100°C. Cross-sectional high-resolution transmission electron microscopy (HRTEM) was used to observe the microstructure of the films. The formation of NCCO crystallites was observed at the film/STO interface, when the post-annealing temperature was higher than 700°C In spite of epitaxial growth of NCCO at the interface, thin films annealed at 700 to 900°C were polycrystalline. Single-crystalline NCCO films with epitaxial relation to STO substrate were obtained by postannealing between 900 and 1000°C. However, in the film annealed at 1050°C, many planar faults and also some buffer layers at the interface were observed in the NCCO crystals. The film annealed at 1100°C contained no NCCO crystal and a secondary phase was observed. From these findings the mechanism of the film growth is discussed.
Adsorption of alkylammonium halide on both hydrophilic and hydrophobic surfaces were investigated by ζ potential and surface force measurements. Silicon oxide and hydrogen-terminated silicon plates were selected as hydrophilic and hydrophobic surfaces, respectively. ζ potentials of the planar surfaces were measured in aqueous solutions of hexadecyltrimethylammonium bromide (C16TAB) in the absence and presence of 1 mM KCl. The surface force measurement was carried out by AFM with silicon oxide or hydrogen-terminated silicon probes in aqueous solutions of C16TAB. Measurements of the two surfaces showed that the dependence of both ζ potential and surface force curve on the C16 TAB concentration were different, respectively. In a high concentration region, beyond critical micelle concentration, the occupied area per unit charge on the silicon oxide surface was 1.4 times larger than that on the hydrogen-terminated silicon surface. In this concentration region, the surface force of the silicon oxide was larger than that of the hydrogenterminated silicon.
The effect of water in the reaction of NaCl with NO2 was investigated by diffuse reflectance infrared spectroscopy. The growth of NO3- absorption showed first order reaction of P(NO2) for water preadsorbed NaCl while the dry reaction of NaCl-NO2 was quadratic. The absorption between 1300 and 1500cm-1 following the process of H20-evacuation-NO2-evacuation-H2O-evacuation-NO2, demonstrated that, after cease of NO3- formation, the exposure to humidity reproduced a fresh H2O adsorbed NaCl surface.