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Information × Registration Number 0215U001294, 0114U004387 , R & D reports Title Low-dimensional and bulk nanocomposite materials for thermoelectric energy conversion popup.stage_title Head Rogacheva Elena, Доктор фізико-математичних наук Registration Date 02-02-2015 Organization The Kharkov state polytechnical university popup.description2 The objects of the research are the polycrystalline Bi-Te, alloys SnTe-In2Te3, Bi2Te3 thin films and Bi-Sb. The goal of the work is a identify the thickness of the quantum oscillations of thermoelectric properties of Bi2Te3thin films and electronic phase transitions in films of Bi-Sb solid solutions and determine the impact of the second phase of the structure and thermoelectric properties of bismuth telluride and tin in the system Bi-Te and SnTe-In2Te3. The research methods are X-ray diffraction; optical microscopy; X-ray photoelectron spectroscopy, electron probe microanalysis, X-ray fluorescence analysis, microhardness measurements at room temperature, conductivity, Hall coefficient and the Seebeck coefficient in the temperature range 77 - 300 K. Based on experimental data defined boundary Bi2Te3 homogeneity in the system Bi-Te, obtained depending on the composition of the properties in the system Bi-Te, which are complex. It was established that in the two-phase region (Bi2Te3 + Te) observed extreme character of the microhardness and charge carrier mobility of staff, which is linked with the processes of ordering in the system of second phase particles (Te). It is shown that long-term aging (25 years) alloys SnTe-In2Te3, where the maximum value observed thermoelectric figure of merit in the two-phase region (SnTe + In2Te3), practically does not change the mechanical and thermoelectric properties. For the first time found that the thickness dependence of thermoelectric properties of Bi2Te3 thin films as n-, and p-type, with a pronounced oscillating character that is interpreted as a manifestation of quantum energy spectrum Bi2Te3. Experimentally determined period oscillations in good agreement with theoretical calculations. It was established that non-monotonic dependence of kinetic coefficients on the composition of the Bi-Sb "thick" films (d = 250-300 nm), which indicate the presence of electronic phase transitions, in good agreement with similar dependences for polycrystalline, indicating the reproducibility of properties in thin film state. Issued recommendations on the use of these effects to control the thermoelectric characteristics in the development of highly efficient thermoelectric materials. Product Description popup.authors Будник Олександр Валентинович Водоріз Ольга Станіславівна Дорошенко Ганна Миколаївна Меньшикова Світлана Іванівна Нащекіна Ольга Миколаївна Рогачова Олена Іванівна Сіпатов Олександр Юрійович Федоров Олександр Григорович popup.nrat_date 2020-04-02 Close