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  • 1
    Electronic Resource
    Electronic Resource
    Electrical properties of antimony telluride (1991)
    Springer
    Applied physics 52 (1991), S. 237-241 
    Details
    ISSN: 1432-0630
    Keywords: 2.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract We investigate the effects of the ambient temperature (T), both temperature (T a )and time (t a )of annealing on the electrical conductivity (σ), and the Seebeck coefficient (S) of Sb2Te3. We concluded that both holes and electrons can participate to the conduction process. The material behaves as a semimetal. Although the Seebeck coefficient possesses a plus sign, the coefficient of S vs. $$\frac{1}{T}$$ plots was negative as a degenerate semiconductor. The decrease in value of S with increasing t a was attributed to a corresponding decrease in the amount of positional disorder which acts as an electron trap center.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00324584
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  • 2
    Electronic Resource
    Electronic Resource
    Crystallization Kinetics of Pb20Ge17Se63 and Pb20Ge22Se58 Chalcogenide Glasses (2000)
    Springer
    Journal of thermal analysis and calorimetry 63 (2000), S. 533-547 
    Details
    ISSN: 1572-8943
    Keywords: chalcogenide glasses ; crystallization kinetics ; differential scanning calorimetry ; Pb–Ge–Se
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Two glasses of the chalcogenide system Pb20GexSe80-x, with x =17 and 22 at.%, were prepared by the melt quench technique. Differential scanning calorimetry emphasized that the investigated Pb20Ge17Se63 and Pb20Ge22Se58 glasses are crystallized to GeSe2 and PbSe2 as well as GeSe2 and PbSe, respectively as revealed by X-ray diffraction analysis. It was found that the glass transition temperatures of the Pb20Ge22Se58 glass are higher than those of Pb20Ge17Se63 ones. The respective values for the activation energy of glass transition (E t ) for Pb20Ge17Se63 and Pb20Ge22Se58 are found to be 434±20 and 761±77 kJ mol-1, while those for the annealed samples are 928±85 and 508±23 kJ mol-1, respectively. The activation energies of crystallization (E c) before and after annealing were determined using different methods. Applying the modified Johnson-Mehl-Avrami (JMA) equation, it could be found that GeSe2 is crystallized by surface crystallization, while both PbSe2 and PbSe are crystallized by bulk crystallization in three dimensions .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010146021940
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  • 3
    Electronic Resource
    Electronic Resource
    Thermal properties of some compositions in the chalcogenide system Sb40Te60-xSex (1991)
    Springer
    Journal of thermal analysis and calorimetry 37 (1991), S. 813-827 
    Details
    ISSN: 1572-8943
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Im Temperaturbereich 320–500 K wurde das Temperaturleitvermögen, die spezifische Wärme und die Wärmeleitfähigkeit der binären Kompositionen Sb40Te60 bzw. Sb40Se60 und der ternären Komposition Sb40Te30Se30 untersucht. Man fand, daß die Umgebungstemperatur, der Se-Gehalt der Kompositionen und die Meßbedingungen entscheidende Faktoren sind, welche sowohl Wert als auch Verhalten der thermischen Parameter, weiterhin den Mechanismus des Wärmetransportes beeinflussen. Obwohl die untersuchten Kompositionen Halbleiterverhalten zeigten, war die freie Ladungsträgerkomponente der Wärmeleitfähigkeit so gering, daß sie vernachlässigt werden konnte. Somit konnte darauf geschlossen werden, daß die beobachtete Wärmeleitfähigkeit sowohl Photonen- als auch Phononenmechanismen zugeschrieben werden kann.
    Notes: Abstract The thermal diffusivities, specific heats and thermal conductivities of the binary compositions Sb40Te60 and Sb40Se60 and the ternary composition Sb40Te30Se30 were measured in the range ∼320 to 500 K. It was found that the environmental temperature, the content of Se in the composition and the conditions of measurements are decisive factors greatly influencing both the values and the behaviour ot the thermal parameters, and the mechanisms of thermal transport. Although the tested compositions exhibit semiconducting behaviour, the free charge carrier component of the thermal conductivity was so small as to be negligible. Thus, it could be concluded that the observed thermal conductivity is attributable to both photon and phonon mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01913162
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  • 4
    Electronic Resource
    Electronic Resource
    Optical properties of Bi2Te2Se thin films (1992)
    Springer
    Journal of materials science 27 (1992), S. 1197-1201 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Some optical parameters of Bi2Te2Se thin films, determined from the measured absorbance and transmittance at normal incidence in the visible spectral range, were studied as functions of film thickness and annealing temperature. These parameters were found to be sensitive to both film thickness and microstructure change caused by annealing in a film. The effect of thickness and temperature of annealing on the optical gap was interpreted in terms of elimination of defects and change of disordering in the amorphous matrix.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01142021
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  • 5
    Electronic Resource
    Electronic Resource
    Optical properties of evaporated Ge20Se80−x Tl x thin films (1996)
    Springer
    Journal of materials science 31 (1996), S. 5759-5764 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Chalcogenide glasses with composition Ge20Se80−x Tl x (x=10, 15, 20, 25, 35%) have been prepared by the usual melt-quenching technique. Thin films of the mentioned compositions have been prepared by the electron beam evaporation. In addition, another set taken from the composition ofX=30 at % with different thicknesses (d=14.7, 30.0, 56.5, 70.0, 101.0, 180.0 nm) have been taken into consideration. The X-ray diffraction (XRD) analysis revealed the amorphous nature of the prepared films. It was found that, in contrast to the optical gap (E op), both the extent of the band tailing (B), and the band gap (E e) increase with increasing thallium content. In other side,E op showed thickness independency. The refractive index (n) showed obvious dependence on both composition and thickness also on the energy of the incident radiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01160825
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