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The problem of designing of more efficient thermoelectric devices has been and remains to be an important and vital problem of physics and technology. Its solution depends directly upon the process of obtaining more efficient thermoelectric materials. Such materials must possess high values of electrical conductivity and Seebeck coefficient as well as the lowest possible values of thermal conductivity. These requirements are in general of a contradictory character. Most quasicrystals exhibit very low thermal conductivity values (1 5 W/Km) with the signature plateau region around 50 150 K, which is typical of many amorphous materials. However, in the plateau region the thermal conductivity of quasicrystals can be almost an order of magnitude higher than the thermal conductivity of many amorphous solids. Even with the low thermal conductivity, quasicrystals have a relatively broad range of electrical conductivity [i.e., 0.01 5000 (Ohmcm)-1]. An advantage of quasicrystals is that the value of electrical conductivity as well as of the thermoelectric power can be modified by varying the composition without sacrificing the low thermal conductivity exhibited in these materials. For these reasons, we have done a systematic investigation of the electrical and thermal transport properties of different quasicrystalline materials, which up to now have not been the subject to investigations for thermoelectric applications. In this paper we focus on the interesting electrical and thermal transport properties of single phase icosahedral Al-Pd Mn.

Thermally Stimulated Currents Measurements (TSC) was used in the study of deep levels in semi-insulating GaN thin film samples, grown on sapphire by the molecular beam epitaxy. Prior to the standard TSC measurements samples were subjected to "thermal cleaning procedure" at certain temperatures in 98 - 250 K range. So obtained TSC spectra were all successfully fitted by the Simultaneous multiple peak analysis method (SIMPA), using the same set of deep levels with activation energies between 0.09 and 0.60 eV, differing only in relative concentrations.

A deep level transient spectroscopy (DLTS) study of electrically active defects in gamma-irradiated, n-type, Czochralski-grown silicon samples at different temperatures has been performed. It is shown that upon irradiation at low temperatures the migration of primary defects is very limited, resulting in formation of only VO centers. At higher temperatures these centers continue to form but the profile of the peak suggests that complex clustering of primary defects around VO centers occurs, contributing to the stress in material. After irradiation at higher temperatures a vacancies become more mobile contributing to the formation of multivacancy-related defects. Besides formation of divacancies, a deep level at Ec – 0.32 eV has been detected in DLTS spectra. This level is identified as divacancy-oxygen V2O complex.

We present a preliminary study of Ge islands formation on Si(100) substrates using grazing-incidence small-angle X-ray scattering (GISAXS). Samples were prepared by a high-vacuum evaporation of a 5nm thick Ge layer on Si(100) substrate held at 200  C. The samples were subsequently annealed at different temperatures for 1h in vacuum, yielding to island formation. A Fortran program IsGISAXS was used for the simulation and analysis of Ge islands. Vertical cut (perpendicular to the surface) of the experimental 2D GISAXS pattern has been fitted using a Guinier approximation. Obtained parameters were used for the simulations. The simulated 2D GISAXS pattern well reproduce experimental data for cylindrically shaped islands with morphological parameters R=4 nm, H/R= 0.25 and the average inter-island distance D=5 nm.