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Dielectric and ac conductivity studies in as-grown Ga2Te3 crystals with the defect zinc-blende structure

Authors

  • Y. Seki,

    1. Graduate School of Science and Technology, Niigata University, IkarashiNinomachi 8050, Nishiku, Niigata 950-218, Japan
    2. Present address: Nippon Light Metal Co.Ltd., 161 Kambara, Shimizu-ku, Shizuoka 421-3297, Japan.
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  • M. Kusakabe,

    1. Department of Applied Chemistry and Biotechnology, Niigata Institute of Technology, Fujihashi 1719, Kashiwazaki, Niigata 945-1195, Japan
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  • S. Kashida

    Corresponding author
    1. Graduate School of Science and Technology, Niigata University, IkarashiNinomachi 8050, Nishiku, Niigata 950-218, Japan
    • Phone: +81 25 262 6131, Fax: +81 25 262 6131
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Abstract

Ga2Te3 crystallizes in the zinc-blende structure where one-third of the cation sites are vacant. The dielectric properties of as-grown Ga2Te3 crystals have been studied in the frequency range from 102 to 109 Hz. Below room temperature, the dielectric constant is around 20 and almost independent of temperature. The ac conductivity is found to obey a power law σac ∼ ωs, with s ∼ 1 indicating that the conduction is due to hopping of localized charge carriers. Above room temperature the dielectric constant shows an S-shaped step-like increase up to a very large value around 104. The relaxation is found to be of thermal activated Debye type, the relaxation time changes as equation image (equation image). The activation energy of the relaxation nearly coincides with that deduced from conductivity. These results are analyzed using the Maxwell Wagner model and the space charge model.

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