Thickness and temperature dependence of electrical properties of Bi2(Te0.1Se0.9)3 thin films
16 Jul 1999-Journal of Applied Physics (American Institute of Physics)-Vol. 86, Iss: 3, pp 1518-1522
TL;DR: In this article, thin films of different thicknesses have been vacuum deposited onto clean glass plates held at room temperature using the flash evaporation technique in a vacuum of 2×10−5 Torr.
Abstract: Thin films of different thicknesses have been vacuum deposited onto clean glass plates held at room temperature using the flash evaporation technique in a vacuum of 2×10−5 Torr. The structural characterization of the bulk and the thin films was carried out using x-ray diffraction, transmission electron microscopy, and selected area electron diffraction techniques. Electrical resistance and thermoelectric power of the films were measured in the same vacuum of 2×10−5 Torr in the temperature range 300–450 K. The conduction activation energy of the films was calculated using the electrical resistivity and thermoelectric power data of the films. The thickness dependence of the activation energy observed is attributed to the polycrystalline nature of the films. Grain growth and reorientation of the grains take place during the annealing process. The thickness dependence of electrical resistivity and thermoelectric power of the films are explained by the effective mean free path model [C. R. Tellier, Thin Solid ...
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TL;DR: In this article, N-type Bi 2 Te 2.7 Se 0.3 thin films with thickness 800nm have been deposited on glass substrates by flash evaporation method at 473 K.
68 citations
TL;DR: In this paper, the effect of different substrates on the structure and morphology of Bi 2 Te 3− y Se y films and relation between Se content in the electrodepositing solutions and in the films were investigated.
37 citations
TL;DR: In this paper, the thermal conductivity of nanocrystalline bismuth telluride thin films using the differential 3ω method, taking into account the thermal contact resistance (TCR) between the substrate and thin-film layers, was estimated.
Abstract: We have estimated the thermal conductivity of nanocrystalline bismuth telluride thin films using the differential 3ω method, taking into account the thermal contact resistance (TCR) between the substrate and thin-film layers. The thin films were prepared on alumina substrates by radio-frequency (RF) magnetron sputtering at temperature of 200°C. Film thickness varied between 0.8 μm and 3.1 μm. The structural properties of the films were analyzed using x-ray diffraction analysis. Their electrical conductivity, Seebeck coefficient, and power factor were evaluated. For measurement of thermal properties by the differential 3ω method, SiO2 thin films were deposited onto the samples, to act as insulating layers. Thin aluminum wire was then patterned onto the SiO2 layer. The observed variations in temperature amplitude as a function of film thickness indicated that the TCR contribution was very small and could therefore be neglected when estimating the thermal conductivity of the thin films. The thermal conductivity of the nanocrystalline bismuth telluride thin films with thickness of 0.8 μm and 2.1 μm were determined to be 0.55 W/(m K) and 0.48 W/(m K), respectively.
27 citations
TL;DR: In this paper, a thermopile sensor consisting of the p-n legs of 2 μm-thickness and 50 μm width, exhibited the sensitivity of 24.8 mV/K.
Abstract: Thermopile sensors were processed on glass substrates by using successive electrodeposition of p-type Sb-Te and n-type Bi-Te thin films, and their thermoelectric characteristics were measured. The thermopile sensor, consisting of the p-n legs of 2 μm-thickness and 50 μm-width, exhibited the sensitivity of 24.8 mV/K. By changing the width of the p-n thin-film legs from 50 to 100 μm, the sensitivity decreased to 15.4 mV/K because of less pairs of the p-n thin-film legs in the thermopile. With increasing the thickness of the thin-film legs from 2 to 5 μm, the sensitivity was improved to 36.5 mV/K due to higher Seebeck coefficients of the 5 μm-thick Bi-Te and Sb-Te films than those of the 2 μm-thick films.
20 citations
TL;DR: In this article, the temperature dependence of the electrical conductivity σ, free carriers concentration n, mobility μ H, and seebeck coefficient S, of the as-deposited and films annealed at different temperatures, have been studied at temperature ranging from 300 to 500 k.
19 citations
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TL;DR: The mean free path of electrons in metals has been studied in this paper, where the authors show that electrons follow a straight line along the path of the electron in the metal atom.
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TL;DR: In this paper, the total resistivity of a thin metal film is calculated from a model in which three types of electron scattering mechanisms are simultaneously operative: an isotropic background scattering (due to the combined effects of phonons and point defects), scattering due to a distribution of planar potentials (grain boundaries), and scattering by the external surfaces.
Abstract: In this paper, the total resistivity of a thin metal film is calculated from a model in which three types of electron scattering mechanisms are simultaneously operative: an isotropic background scattering (due to the combined effects of phonons and point defects), scattering due to a distribution of planar potentials (grain boundaries), and scattering due to the external surfaces. The intrinsic or bulk resistivity is obtained by solving a Boltzmann equation in which both grain-boundary and background scattering are accounted for. The total resistivity is obtained by imposing boundary conditions due to the external surfaces (as in the Fuchs theory) on this Boltzmann equation. Interpretation of published data on grain-boundary scattering in bulk materials in terms of the calculated intrinsic resistivity, and of thin-film data in terms of the calculated total resistivity suggests that (i) the grain-boundary reflection coefficient in Al is \ensuremath{\approx} 0.15, while it is somewhat higher in Cu; (ii) the observed thickness dependence of the resistivity in thin films is due to grain-boundary scattering as well as to the Fuchs size effect; and (iii) the common observation that single-crystal films possess lower resistivities than polycrystalline films may be accounted for by grain-boundary effects rather than by differences in the nature of surface scattering.
1,842 citations
TL;DR: The dominant features of the band structure have been analyzed by studying the fundamental reflectivity over the energy range 0.1-12 eV and the absorption over the range 0,1-1.5 eV as mentioned in this paper.
210 citations
TL;DR: In this article, the electrical conductivity, thermoelectric power and thermal conductivity were measured on Bi2Te3 and the alloy systems (Bi,Sb) 2Te3, Bi2(Te,Se)2 and Bi2Sb 2 Te3, with a temperature difference of 65°C between the hot and cold junctions, with the hot junction at 300°K.
209 citations