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  • 1
    ISSN: 1432-0630
    Keywords: 78.50
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Ternary ZnSxSe1−x polycrystalline thin films were prepared by evaporation in vacuum of 10−5 Torr. The molecular fractionx varied in the region o≦x≦1. The optical constants (the refractive indexn, the absorption indexk, and the absorption coefficientα) were determined in the wavelength range 300–1600nm. A plot representingα 2=f(hv) shows that the ZnSxSe1−x polycrystalline thin films of different compositions have two direct transitions corresponding to the energy gapsE andE+Δ. The variation in eitherE orE+Δ withx indicates that this system belongs to the amalgamation type. Such variation follows a quadratic equation. The bowing parameter was found to be 0.456 eV, roughly equal to the calculated value 0.60 eV using the empirical pseudopotential method based on the virtual-crystal approximation, in which the disorder effect has not been taken into account.
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  • 2
    ISSN: 1432-0630
    Keywords: 78.20.-e ; 81.15.-z
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Solid solutions of ZnSe x Te1−x (0. 1 ≤x ≤ 1) were synthesized by vacuum fusion of stoichiometric proportions of ZnSe and ZnTe. X-ray diffraction data revealed that they have polycrystalline cubic zinc-blende structure. The calculated unit cell lattice constant (a) for the different compositions in powder form vary linearly, with molecular fractionx following Vegard's law:a(x) = 6.165 – 0.485x. Thin films of ZnSe x Te1−x (0.1 ≤x ≤ 1) solid solutions deposited onto glass or quartz substrates by thermal evaporation in a vacuum of 10−4 Pa were found to be polycrystalline with a preferred (1 1 1) orientation. The obtained data were confirmed by electron diffraction. The optical studies showed that ZnSe x Te1−x polycrystalline films of different compositions have two direct transitions with corresponding energy gapsE g andE g +Δ so The variations in bothE g andE g +Δ so, withx indicate that ZnSe x Te1−x solid solution belongs to an amalgamation-type following quadratic equations with bowing parameters 1.251 and 1.275, respectively.
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  • 3
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 9 (1990), S. 79-82 
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 6
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 3 (1992), S. 71-76 
    ISSN: 1573-482X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Complete solid solutions of CdS x Se1−x (0≤x≤1) were synthesized by vacuum fusion of stoichiometric proportions of CdS and CdSe. X-ray diffraction data revealed that they possess the hexagonal wurtzite structure. The unit cell lattice constants vary linearly with the composition parameter,x, following Vegard's law. Thin films of CdS x Se1−x (0≤x≤1) solid solutions could be deposited onto glass substrates by thermal evaporation of the bulk material in 10−4 Pa vacuum. Structural investigation showed that the films are polycrystalline with predominant appearance of the (002) reflecting plane. On annealing at 250°C in 10−2 Pa vacuum atmosphere, aggregation and rearrangement of the as-deposited tiny crystallite occurred, preserving the same crystal structure. The dark electrical resistivity of the films is independent on the film thickness, but it varies appreciably with the composition parameter,x, showing a minimum resistivity of 0.02 Θ cm atx=0.55. The temperature dependence of the resistivity follows the semiconducting behaviour with an extrinsic and an intrinsic conduction below and above 70°C, respectively. The determined activation energies 0.2 eV and 0.8 eV, respectively, correspond to shallow and deep trap levels, respectively.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 3 (1992), S. 232-236 
    ISSN: 1573-482X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The structural properties of the 50 mol% Ga2Se3-50 mol% Ga2S3 system in thin-film form were studied using an X-ray diffraction technique. As-deposited films had an amorphous nature, whereas films heat treated for 2 h at 400 °C in a vacuum of 10−2 Pa had a single-phase (cubic) polycrystalline nature with lattice constanta=0.532 nm. The optical properties of Ga2Se3-Ga2S3 thin films as-deposited and as-heat treated were also studied. It was found that heat treatment strongly affects the optical constants as well as the energy gap, which can be attributed to compositional as well as structural changes.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 52 (1991), S. 353-357 
    ISSN: 1432-0630
    Keywords: 78.50
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The optical constants (the refractive index n, the absorption index k, and the absorption coefficient α) of CdIn2Se4 thin films were determined in the spectral range of 500–2000 nm. Graphical representation of log(α) as a function of log(1/λ) shows two distinct, linear parts indicating the existance of both direct and indirect optical transitions. The corresponding forbidden energy gaps E g d and E g Emphasis〉d were determined. The effect of both annealing temperature as well as the substrate temperature on the optical constants of CdIn2Se4 thin films was also investigated.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0630
    Keywords: PACS: 78.20. ; e; 81.15. ; z
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract.  Solid solutions of ZnSe x Te 1-x (0.1≤x≤1) were synthesized by vacuum fusion of stoichiometric proportions of ZnSe and ZnTe. X-ray diffraction data revealed that they have polycrystalline cubic zinc blende structure. The calculated unit cell lattice constant (a) for the different compositions in powder form vary linearly, with molecular fraction x following Vegard’s law: a(x)=6.165−0.485x. Thin films of ZnSe x Te 1-x (0.1≤x≤1) solid solutions deposited onto glass or quartz substrates by thermal evaporation in a vacuum of 10-4 Pa were found to be polycrystalline with a preferred (1 1 1) orientation. The obtained data were confirmed by electron diffraction. The optical studies showed that ZnSe x Te 1-x polycrystalline films of different compositions have two direct transitions with corresponding energy gaps E g and E g+ΔSO The variations in both E g and E g+ΔSO with x indicate that ZnSe x Te 1-x solid solution belongs to an amalgamation-type following quadratic equations with bowing parameters 1.251 and 1.275, respectively.
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