Analytical expressions for the characteristics of double monochromators have been derived on the basis of a universal mathematically correct approach developed previously. These expressions are combined with simple geometric diagrams added to explain the features of instrument operation.
The problem of choosing the optimal conditions to obtain informative signals during the optoelectronic monitoring of periodic structures with element sizes in the micron and nanometer ranges is considered.
The morphology of a cleavage surface of single-crystal bismuth has been studied by atomic force microscopy after treatment in atomic hydrogen. It has been ascertained that the surface relief changes due to the formation of micro- and nanocrystalline structures.
The influence of the granule size of zinc oxide powders on the diffuse reflection spectra and their modifications caused by electron irradiation are investigated in the size range of 70–630 μm. It is ascertained that the reflection coefficient before irradiation and the coefficient of absorption induced by irradiation vary along the curves with maxima near approximately 130 μm as a function of the ZnO granule size.
The gradual degradation of green-range pulse lasers based on ZnSe-containing quantum-well structures with optical and electron-beam pumping has been investigated. The operation of the lasers over several hours without decreasing the output power (with the active elements at room temperature and a pulse repetition rate of 50 Hz) has been shown.
The energy spectra of electrons reflected from a gold layer deposited onto a silicon substrate have been measured when the energy losses are comparable with the energy of a probe electron beam (5 keV) and the elastic energy losses correspond to an electron-beam energy of 14 keV. A subsequent theory for calculating the energy spectra of electrons and light ions reflected from a multilayer target, which is used to interpret the energy spectra measured in the wide range of energy losses, has been developed. It is found that the elastic scattering processes in the gold layer (the thickness of which is tens of monolayers) substantially affect formation of the energy spectra. The Au layer thicknesses calculated by means of the developed theory are compared with those determined from the spectra of elastically reflected electrons. The errors of the Au layer thickness measurements via the proposed method are discussed.
The secondary emission of carbon atoms from the (0001) plane of graphite nanocrystallites bombarded with argon ions with energies of 1 and 10 keV and the incidence angle α = 45° is investigated. The unusual oscillating energy distributions of secondary C+ ions with main maxima E max in the range of 40–60 eV and peaks corresponding to the energies E 1 ≈ 20, 30, 70, 80, and 100 eV have been revealed. The C+ ion yield decreases, the energy spectrum increases, and the maximum E max shifts to larger energies E 1 with increasing emission angle (with respect to the normal to the surface). The secondary-ion emission from the (0001) face of graphite is numerically simulated with allowance for the charge exchange of secondary ions to obtain a qualitative explanation of the observed results.
It is shown by means of the thermal neutron diffraction method that, during the doping of Zn-chalcogenide semiconductor crystals with 3d ions, elongated distortions whose spatial topology depends on the type of impurity can be formed in the sphalerite modification based on the initial crystal structure. Experimental results are discussed using the concept of vibronic interaction induced by foreign ions with partially filled outer electron shells in the cubic crystal field.
The temperature dependence of the generation kinetics of F centers and their aggregates in a LiF/Si(111) thin-film system after irradiation with low-energy (80-eV) electrons was studied by total current spectroscopy. It was shown that, in all cases, low-temperature annealing results in degradation of the formed centers followed by their coalescence. A new absorption band with an energy of 3.6 eV corresponding to anionic cluster complexes was found.
A method for the creation of scanning patterns obtained by scanning probe microscopy (SPM) has been proposed. The algorithm allows scanning patterns to be formed when the values of the distortions along the z -axis are minimized and the shapes and sizes of the objects remain unchanged. To remove interline jumps the method of preliminary data filtering is based on a formalized choice of the height range which allows us to increase the automation degree of data processing and the reliability of the data. Model SPM patterns were used for testing.
The structure, phase composition and dislocation substructure of 20Cr23Ni18 steel subjected to electron-beam treatment and subsequent multicycle fatigue loading until destruction were studied by scanning and transmission electron microscopy. It was shown that electron-beam treatment with an energy density of 20 J/cm2 increases the fatigue durability by a factor of 2.1. The cause of steel fatigue destruction is analyzed and a way of further increasing the fatigue durability is proposed.
The focusing of atomic and molecular particles near the nanotube axis using a model of a carbon nanotube (CNT) with discrete arrangement of atoms in its wall is studied. The degree of focusing of channeling particles in CNTs depends not only on the diameter of the CNTs, but also on its chirality. It is shown that the concentration of channeling particles in the tube's central part is higher for chiral nanotubes.
A computational method for determining the real sizes of quantum dots based on the data of atomic force microscopy (AFM) is suggested. It is shown that the experimentally observed measurement error (for the AFM method) of the sizes of the pyramidal quantum dots with a base edge of a ∼ 30–46 nm, stemming from convolution, is approximately equal to a quarter of the curvature radius of the AFM probe. Calibration curves of the dependence of the photoluminescence-peak positions of InAs-QD/GaAs heterostructures (in the range 900–1800 nm) on the sizes of the quantum dots measured with the probes whose curvature radii were from from 10 to 100 nm are established.
The current induced by emission from a thin 63Ni layer is simulated with allowance for the real spectrum of ejected electrons and their angular distribution in Si and GaN. The calculated results are compared with simulation data obtained for a monoenergetic electron beam perpendicular to the semiconductor detector. For both Si and GaN, the ratio between the currents induced by the SEM beam and β emission from 63Ni is demonstrated to be almost completely independent of the diffusion length, if the electron-beam energy of a scanning electron microscope (SEM) is appropriately selected.
The results of studying the formation of the three-dimensional micromechanical structure of an integral tensoconverter are presented. The technological restrictions on contact photolithography over the relief structure formed on the device layer of the silicon-on-insulator wafer are analyzed. The effect of the design parameters (the frame height and the width of the frame slit) are described.
The accumulation of deuterium in an assembly of nickel foils by the pulsed irradiation of a deuterium plasma is studied. It is established that implanted deuterium is transferred to a much greater depth than that corresponding to the projective range of deuterium plasma ions with a maximum velocity of 108 cm/s. The maximum concentration (up to 4 at % deuterium) is observed in the second Ni foil. The observed phenomenon can be explained by the action of shock waves and concomitant stresses on the transport and redistribution of deuterium to greater depths.
Zinc-blend III–V semiconductors being cleaved along nonpolar (110) planes yield atomically clean surfaces due to their charge neutrality, which can be employed as mirror planes for optical resonators. As a result of the Ga3 d core level photoemission measurements after the n -, p -GaAs (110) plane cleavage in situ of doped semiconductors with 14 nominally identical p - n homojunctions having optically flat cleaved surface under the optical microscope inspection, the estimate of the Fermilevel positions on energy scale were acquired for p - and n -epilayers. The two-dimentional photoemission image for p - n homojunction was studied as well, using the focused synchrotron radiation beam (diameter 0.7 μm, 95 eV, ∼10 10 phot./s) at the scanning photoemission microscope. The average value of surface band bending for p -epilayer measured from the energy position of ideal flat-band conditions, was equal to 0.12 ± 0.05 eV, and that for n -epilayer—0.16 ± 0.08 eV, the spectrometer energy resolution being <0.15 eV. The detailed analysis of the experimental data was carried out in order to clarify the deviation fsrom ideal flat band conditions characteristic for absence of surface cleavage defects. Comparison was done with the well-known literature data on theoretical and experimental investigations of cleavage defects. The experimental results leading to different deviations from ideal flat-band conditions for each cleavage are explained by extrinsic local microscopic defects of cleavage which can appear accidentally and unpredictably, since the system dynamics during cleavage is a highly nonlinear many-body process with many degrees of freedom.
