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The role of surface compounds in the oscillating anodic reactions on nanostructured electrodes has been examined by computer simulation of the oscillating anodic oxidation of formaldehyde on Ag nanostructures and the oscillating reaction design based on the autocatalytic reduction of Pd surface compounds by hypophosphite in Ag-Pd nanostructures. Experiments and computer simulations show that the surface...
The measurements of surface potential SP and resistance changes ΔR of thin Pd and Ti films in the process of PdH x (x = 1) and TiH y (y = 2) hydride formation were performed. SP measurements allow differentiation between various forms of hydrogen adspecies. The influence of these forms of the adsorbate on the resistance are determined and discussed.
The explicit formulae for the Green functions are given for the bulk crystal, for a crystal with surface and for finite-thickness thin layers adsorbed on a surface as a function of microscopic interaction parameters. The case of the (001)Fe surface and of epitaxial layers of W on the same surface is studied on the basis of the experimental dispersion curves. The vibrations of atoms at any distance...
The results of field emission microscopy measurements of the diffusion of water deposited on a thermally clean and a gold covered tungsten emitter are presented. The diffusion of wafer from a multilayer to a submonolayer H 2 O was observed on clean W in the temperature range 126-147 K and on Au/W Θ ≥ 2) in the range 113-123 K, with activation energies for diffusion of 27±2 kJ/mol in both cases...
K 3 Na(SeO 4 ) 2 single crystal cleaved surfaces were imaged by means of an atomic force microscope in air. The images revealed atomically flat terraces 500 nm wide, with steps, this height being the multiple of the K 3 Na(SeO 4 ) 2 c/2 lattice constant. For the first time, atomic resolution was observed on the KNSe crystal surface in air. Correlation...
Thermonuclear plasma-wall interaction is accompanied by intensive backscattering of light ions and atoms, which influences strongly the mass and energy transfer between the plasma and construction materials. Backscattering of atomic particles from solids plays an important role in the modification of materials by ion beams and also as a means of studying the near surface region by low energy ion scattering...
Using the cluster version of the local-density approximation method, we have studied the dopant's influence on the electronic structure of the Al/Si(111) interface. P atoms were placed in the fifth silicon double-atomic layer (DAL) counting from the interface. The second DAL was doped with either Ga or As. The Schottky barrier height was found to be 0.75 eV in the Al/Si(pure) cluster system and 0...
Use of the method of ion thermoemission noise has shown a distinct difference between the values of diffusion energy obtained for the surface diffusion of Li and K isotopes on the tungsten surface. In order to study the effect in detail, separated, almost monoisotope samples were used: Li-6, Li-7, K-39, K-41. The following surface diffusion energies have been obtained: E(6): 0.61 eV, E(7): 0.67 eV,...
Behaviour of a sub-monolayer Au-coverage on the vicinal Si(111) has been studied by RHEED. For the sample misoriented by 8.46° towards the [112] azimuthal direction at the coverage equal to 0.20 ML of Au, the RHEED pattern showed almost perfect distribution of the monoatomic Si(111) steps with the staircase width equal to 18.52±0.66 . Au-induced order was identified with the (755) facet of Si with...
Electron-exchange processes in excitations within the d-multiplet of the TM-ions in NiO(100) and CoO(100) had been examined by spin-polarized electron energy-loss spectroscopy. The excitations at surface and bulk ions in NiO show a completely different scattering geometry dependence, providing the possibility of distinguishing between both. In addition to the well-known 0.6 eV surface state, the loss-structure...
The segregation of carbon in monocrystalline iron has been studied using the AES method. Depending on the carbon concentration in bulk and on the temperature, there are three forms of carbon on the clean iron surface: graphite, molecular carbon and atomic carbon. The results of the segregation kinetics studies have been discussed considering the real mosaic structure of monocrystalline samples. The...
The structural changes in C 60 /C 70 :Ni layers annealed at a temperature of 620 K were observed by Raman spectroscopy, electron diffraction, AFM and HRTEM methods. The 'as grown' C 60 /C 70 :Ni layers exhibit the features of the amorphous structure, which is confirmed by broadened Raman bands of H g (1) fullerene mode, diffused rings in...
Photoreflectance spectroscopy has been applied to investigate MBE grown GaAs/AlGaAs low dimension structures. The first is an HEMT type structure with buried 10 periods of 2.5nm GaAs/2.5 nm AlGaAs superlattice. Oscillation-like signals associated with this SL have been observed and analysed in terms of the Franz-Keldysh oscillations (FKO) related to the presence of free carriers in the miniband structure...
The work function change (ΔΦ) that occurs upon CO chemisorption on PdCu(110) single crystal was studied using the Kelvin probe technique. The ΔΦ measurements were carried out for various surface compositions ranging from 100% Pd to 100% Cu, which were prepared by sputtering and annealing the sample at different conditions. Auger Electron Spectroscopy (AES) and Thermal Desorption Spectroscopy (TDS)...
The results of field emission microscopy investigation of the adsorption and thermal desorption of wafer deposited on a thermally clean and gold-covered tungsten emitter are presented. The desorption experiments indicate that H 2 O molecules dissociate in contact with surfaces of the clean tungsten emitter, but no traces of dissociation of water adsorbed on Au/W were found, if only the gold...
The complex coordinate method, widely used in theoretical atomic spectroscopy, is applied to study the energies and tunnelling times in the process of resonant electron tunnelling through zero-dimensional semiconductor nanostructures. A spherical rectangular barrier well potential is used as a model of a quantum dot. Resonant states of different angular symmetry are studied vs the radius of the dot...
The Brodie's expression (BE) for the work function (WF) is used to calculate the WF of transition metals. It is shown that the values of WF calculated from BE agree both with those measured for polycrystalline samples and those calculated ab initio for transition metals. The best agreement is observed in the first middle of the d metal series.
The electronic structure of a terminated effective-mass superlattice (EMSL) is investigated taking into account the effect of the EMSL surface (i.e. the EMSL/substrate interface). Special attention is paid to the conditions under which two neighbouring mini-band edges cross each other which results in the vanishing of a corresponding mini-gap for certain EMSL bulk parameters (the so-called zero energy...
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