Optical characterization of rocksalt Pb1–xSnx Te alloys

Authors

  • Nilton Souza Dantas,

    1. Department of Materials Science and Engineering, Royal Institute of Technology, 100 44 Stockholm, Sweden
    2. Área de Informática, Departamento de Ciências Exatas, Universidade Estadual de Feira de Santana, 44031-460 Feira de Santana, Ba, Brazil
    3. Instituto Nacional de Pesquisas Espaciais, INPE/LAS-C.P. 515, 12210-970 São José dos Campos, SP, Brazil
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  • Hans Arwin,

    1. Laboratory of Applied Optics, Department of Physics, Chemistry and Biology, Linköping University, 58 183 Linköping, Sweden
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  • Gabriel Nzulu,

    1. Laboratory of Applied Optics, Department of Physics, Chemistry and Biology, Linköping University, 58 183 Linköping, Sweden
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  • Paulo Henrique de Oliveira Rappl,

    1. Instituto Nacional de Pesquisas Espaciais, INPE/LAS-C.P. 515, 12210-970 São José dos Campos, SP, Brazil
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  • Antônio Ferreira da Silva,

    1. Instituto de Física, Universidade Federal da Bahia, Campus Universitário de Ondina, 40210-340 Salvador, Ba, Brazil
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  • Clas Persson

    1. Department of Materials Science and Engineering, Royal Institute of Technology, 100 44 Stockholm, Sweden
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Abstract

The optical properties in terms of dielectric function ϵ (ħω) = ϵ1(ħω) + 2(ħω) of rocksalt Pb1–xSnx Te alloys (0 ≤ x ≤ 1) are investigated experimentally by spectroscopic ellipsometry and theoretically by first-principles electronic band structure calculation. We find a strong optical response in the 0.5–2.0 eV region arising from optical absorption around the LW-line of the Brillouin zone. The response peak of the imaginary part of the dielectric functions at E = 1.6–1.8 eV shifts towards lower energies for high Sn compositions as a consequence of narrower W-point band-gap Eg(W) for the Sn-rich alloys. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

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