The electric and photoelectric properties of very thin discontinuous antimony films deposited on an insulating (sapphire) substrate were investigated in order to explain the "surfactant" role of Sb atoms in the growth of other metal films on this substrate. The results show that the properties of pure Sb films on a sapphire are similar to those observed for other metals and cannot explain an essential change in the growth of Ag, Au, Ga and other metals when the substrate is pre-germinated with antimony.
In this work, we studied the Raman spectra of thick polycrystalline Cd_{1-x}Zn_x Te (CZT) films with x ranged from 0.06 to 0.68. Additionally, the surface morphology and structural properties were studied in order to determine the crystalline quality of the samples. The Raman spectra had a two-mode behavior typical for CZT solid solution and showed CdTe- and ZnTe-like longitudinal and transverse optical modes. The relationship between the frequencies of CdTe- and ZnTe-related modes on x was studied. We observed the deviation of the compositional dependence of phonon mode frequencies for polycrystalline CZT films in comparison with a similar dependence for CZT single crystals. Such deviation was caused by the effect of structural defects in polycrystalline films on frequencies of vibrational modes. The values of excitation wavelength, which allow achieving of high signal-to-noise ratio on the Raman spectra of CZT films with different zinc concentration in the result of resonant enhancement of phonon modes intensities, were experimentally determined.
Structural, optical and electrical properties of Zn-doped CuInS_2 thin films grown by double source thermal evaporation method were studied. Evaporated thin films were grown from CuInS_2 powder by vacuum evaporation using resistively heated tungsten boats. The element Zn was evaporated from a thermal evaporation source. The amount of the Zn source was determined to be 0-4% molecular weight compared with CuInS_2 source. The effects of Zn on films properties were investigated using X-ray diffraction, optical transmission and reflection spectra. The films were annealed in vacuum at 260°C for 2 h. The Zn-doped samples have band-gap energy of 1.474-1.589 eV. We found that the Zn-doped CuInS_2 thin films exhibit p-type conductivity and we predict that Zn species can be considered as suitable candidates for use as doped acceptors to fabricate CuInS_2-based solar cells.
The chemical reactions are widely used for the layers of different composition formation. However, synthesis mechanism is a complicated process in thin films/layers system, and is not completely studied. The purpose of this paper was to analyze the kinetics of chemical compounds in reaction, to produce ZrO₂ thin films using arc evaporation and annealing (post-deposition), and to analyze them. The pure zirconium (Zr) and zirconium nitride (ZrN) were deposited using arc evaporation. 10% mol of aluminum was evaporated on a few Zr films. All deposited films were annealed in the air atmosphere gradually changing the temperature from 400°C to 1100°C in order to produce ZrO₂ films. The formation processes of the new phase were studied. Activation energy of the reactions was calculated. Structural properties were measured using X-ray diffraction, optical properties - using ellipsometry. Tetragonal phase of ZrO₂ was obtained in the annealing process of ZrO₂/Al thin film in the air atmosphere of 800°C.
In the paper the design and application of a time-of-flight low energy ion scattering instrument built into an UHV complex deposition and analytical apparatus is described. A special attention is aimed at demonstrating the ability of time-of-flight low energy ion scattering to analyse near-to-surface layers of thin films prepared both ex situ and in situ. It is shown that the broadening of peaks in time-of-flight low energy ion scattering spectra can be attributed to multiple scattering and inelastic losses of ions in deeper layers. As a result of that, the peak width of ultrathin films depends on their thickness.
A series of ZnSe single layers having thickness between 30 nm and 1 μm was deposited on c-Si and glass substrates at room substrate temperature. Thermal evaporation of ZnSe powder in high vacuum has been applied. Moreover, SiO_x/ZnSe periodic multilayers prepared by the same deposition technique and having ZnSe layer thickness of 2 and 4 nm have been studied. Raman spectra were measured at 295 K, using the 442 nm line of a He-Cd laser as well as different lines of the Ar^+ or Ar^+/Kr^+ lasers. The observed Raman features have been related to multiple optical phonon (1LO to 4LO) light scattering and connected with the existence of randomly oriented crystalline ZnSe grains in both ZnSe single layers and ZnSe layers of the multilayers. Relatively large line width ( ≈ 15 cm^{-1}) of the 1LO band has been observed and related to lattice distortion in the crystalline grains and existence of amorphous phase in the layers thinner than 100 nm. The Raman spectra measured on both ZnSe single layers and SiO_x/ZnSe multilayers using the 488 nm line with a gradually increased laser beam power indicate an increased crystallinity at high irradiation levels.
Results concerning the morphology of Cu adsorption layers deposited from vapor under ultrahigh vacuum on Ir tip and the influence of oxygen on this morphology are reported. The method employed was field electron emission microscopy. It was found that the presence of oxygen decreases the copper wettability of iridium. Preadsorption of oxygen on the Ir surface is followed by an increase in cohesion interaction between atoms of the Cu deposited onto the tip at room temperature. Coadsorption of Cu and O on the Ir tip surface at liquid nitrogen temperature, when followed by gradually heating the adlayer, results in crystallization of the deposit in the temperature range from 430 K to about 700 K. Some evidence indicates the formation of Cu_{2}O with a high degree of crystallinity under these conditions. Cu and O coadsorption on the Ir surface at a temperature higher than 1090 K leads to selective accumulation of Cu on the {111} faces and to formation of epitaxial crystals which are oriented to the substrate in the same manner as the Cu crystals grown at ultra-high vacuum from Cu flux containing no oxygen. Oxygen incorporated into the Cu beam interact preferentially with {011} and {001} Ir faces, where it can produce oxide layers.
The work presents a novel method of production of mesoscopic metallic wires on semiconducting surfaces. Making use the self-assembly phenomenon, arrays of extremely long and perfectly parallel mesoscopic Pb-wires on vicinal Si(111) substrates are formed and studied in UHV conditions. Before deposition of Pb a uniform distribution of monoatomic steps and terraces was induced by formation of Au chains running along step edges. The wires growing on the substrates held at temperatures close to the room temperature reach up to 8 µ length. A reflection high electron energy diffraction experiment shows that the wires laying on Si(533) along the step edges have triangular cross-section determined by (111) and (100) facets of Pb. Scanning tunneling microscopy images collected at low temperatures have enabled us to determine details of the wires shape and morphology of the substrate. The width of the wires was approximately equal to 60 nm whereas their height was about 10 nm. The observed strong growth anisotropy is attributed to step edge barriers and high Pb mobility on the smooth Si(111) narrow terraces that form vicinal surfaces and the anisotropic strain due to large misfit between Pb and Si lattices.
Switching magnetization magnetic force microscopy (SM-MFM) is based on two-pass magnetic force microscopy with opposite orientation of tip magnetization between two scans. The sum of the scanned data with reversed tip magnetization depicts local van der Waals forces, and their difference maps the local magnetic forces. Tip magnetization can be easily reversed in external magnetic field during the scanning. The separation of the forces mapped enables scanning in close proximity of the sample (~5 nm). Therefore, extremely high spatial resolution (10 nm) is achievable by the SM-MFM. Image phase resolution of the MFM method depends on various geometric parameters of the tip, such as tip length, its apex radius and taper angle. The parameters are determined by the evaporation process, within which the standard atomic force microscopy tips are coated with magnetic layer. In this work we show that the thickness of the coated layer is important for the SM-MFM spatial resolution.
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