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[en] The results of observation of the charge carrier generation and the electromotive force appearance on homogeneously heated n-type silicon-germanium films, heavily doped with titanium and grown by deposition from the gas phase on silicon p-type substrates are presented. The maximum value of the electromotive force of 3 mV is recorded in the temperature range 500-600 K at a dark short-circuit current of 0.5-1 μA, the value of which increases with increasing temperature and reaches 3 μA at 900 K. When the contacts are placed on the film and on the substrate, that is when the parameters of the Si-Ge/Si structure proper are measured with its homogeneous heating, the dark current density at 700 K is 2 μA/cm2, and the volume thermoelectric power is 4 mV. (authors)
[en] The results of the thermovoltaic effect studies in silicon-germanium film p-n structures obtained by gas-phase deposition in vacuum have been presented. It has been shown that under uniform heating with no temperature gradient in these film structures there is a dark voltage, and the effective generation of carriers occurs, which can be used for developing the effective converters of thermal energy in electric one, including a non-photoactive component of solar radiation. (author)
[en] Results of investigations of the thermovoltaic effect in nonirradiated and γ-irradiated (109 rad) silicon p-n-films obtained by thermal vacuum deposition are presented. It is shown that at uniform heating in absence of temperature gradient in these film structures the dark voltage arises and the effective generation of carriers occurs. This effect can be used for the development of the converters of thermal energy, including the nonphotoactive component of solar radiation. The conclusion has been made about the important role of intrinsic structural defects in the thermovoltaic effect in silicon structures. (authors)
[en] Full text: The results of theoretical and experimental studies of the thermoelectric phenomena in the granulated semiconductors have been presented. A model of the heterogeneous semiconductor medium consisting of di phasic granules, which are the crystal semiconductor grains covered by the oxide nanofilms has been proposed. This effective medium model (EMM) consisting of the set of contacting granules has been constructed. Each granule phase is characterized by its own conductivity σi, heat conductivity χi, Seebeck factor αi, characteristic size di and, accordingly, efficiency of thermoelectric transformation Zi (i=1,2). On the basis of the linear Onsager thermodynamics the expressions for the estimation of σeff, χeff, αeff and Zeff are constructed, and their values depending on degree of asymmetry of characteristics of the granule components are analyzed. In framework of this method the more complicated ternary media is considered too. The possibilities of acquisition of the optimal medium characteristics under various technological conditions and under action of ionising radiation (electrons and γ-irradiation) have been studied. The developed model has been tested on the samples of polycrystalline and microgranular silicon with the various size of grains. The thermoelectric parameters of these materials have been studied. Conditions of obtaining of the big αeff and Zeff values are found. It is shown that radiation is a fine tool to control the properties of the effective medium and can be considered as a technology factor. A satisfactory agreement of EMM both with the previous experiments , and with the present ones has been obtained. (authors) References: 1. B.M.Abdurakhmanov, M.M.Adilov, M.H.Ashurov, H.B.Ashurov, B.L.Oksengendler. Appl. Solar Energy. 2011. V.47.No 2. P.139.