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Публікація Growth and structure of thermally evaporated Bi2Te3 thin films(Elsevier, 2016) Rogacheva, E. I.; Budnik, A. V.; Dobrotvorskaya, M. V.; Fedorov, A. G.; Krivonogov, S. I.; Mateychenko, P. V.; Nashchekina, O. N.; Sipatov, A. Yu.The growth mechanism, microstructure, and crystal structure of the polycrystalline nBi2Te3 thin films with thicknesses d = 15 – 350 nm, prepared by thermal evaporation in vacuum onto glass substrates, were studied. Bismuth telluride with Te excess was used as the initial material for the thin film preparation. The thin film characterization was performed using X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, scan electron microscopy, and electron force microscopy. It was established that the chemical composition of the prepared films corresponded rather well to the starting material composition and the films did not contain any phases apart from Bi2Te3. It was shown that the grain size and the film roughness increased with increasing film thickness. The preferential growth direction changed from [00l] to [015] under increasing d. The X-ray photoelectron spectroscopy studies showed that the thickness of the oxidized surface layer did not exceed 1.5 – 2.0 nm and practically did not change in the process of aging at room temperature, which is in agreement with the results reported earlier for single crystals. The obtained data show that using simple and inexpensive method of thermal evaporation in vacuum and appropriate technological parameters, one can grow n-Bi2Te3 thin films of a sufficiently high quality.Публікація Transport properties of the bismuth telluride thin films with different stoichiometry in the temperature range 77-300 K(Науково-технологічний комплекс "Інститут монокристалів", 2020) Rogacheva, E. I.; Novak, K. V.; Doroshenko, A. N.; Nashchekina, O. N.; Budnik, A. V.The objects of the present study are thin films with thicknesses d = 45-620 nm prepared by thermal evaporation in vacuum from a single source, using undoped p- and n-type Bi₂Te₃ polycrystals with different stoichiometry (60.0 and 62.8 at. % Te, respectively) as a charge, and subsequent condensation on glass substrates at 500 K. The temperature dependences of the Hall coefficient Rн, electrical conductivity σ, and Hall charge carrier mobility μн of thin films were obtained in the range 77-300 K. It was found that the films had the same type of conductivity as the initial polycrystals in the entire temperature range studied and, like in the initial crystals, σ and μн decreased with increasing temperature. The exponents ν in the μн(T) dependences for the bulk polycrystals were larger than those for the films and increased with increasing d. In contrast to the p-type bulk polycrystals, Rн of the p-type films decreased under increasing temperature. In the n-type Bi₂Te₃, Rн decreased with temperature for both thin films and bulk crystals, however, the character of the Rн(T) dependences for the crystals and films differed. The decrease in Rн with temperature before the range of intrinsic conductivity in all thin films is attributed to the existence of donor and acceptor defect states.