Frequency-dependent conductive behavior of polymer-derived amorphous silicon carbonitride

    Authors

    B. S. Ma; Y. G. Wang; K. W. Wang; X. Q. Li; J. L. Liu;L. N. An

    Comments

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    Abbreviated Journal Title

    Acta Mater.

    Keywords

    Frequency-dependent conduction; Polymer-derived ceramics; Amorphous; SiCN; Free carbon; PYROLYSIS TEMPERATURE; ELECTRICAL-PROPERTIES; SIALCN CERAMICS; PIEZORESISTIVITY; TRANSPORT; OXIDATION; Materials Science, Multidisciplinary; Metallurgy & Metallurgical; Engineering

    Abstract

    The AC conductive behavior of a polymer-derived amorphous silicon carbonitride ceramic was systemically studied. The conductivity exhibited a frequency-dependent switch: at low frequencies, the conductivity is constant and independent of frequency; while at high frequencies, the conductivity increases with frequency, showing a strong relaxation process. Both the frequency-independent conductivity and the characteristic frequency for the relaxation follow the Arrhenius relation with respect to the annealing temperature and follow a band-tail hopping process with respect to the testing temperature. XPS analysis revealed that a sp(3)-sp(2) transition took place in the free-carbon phase of the material with increasing annealing temperature. The activation energy of the transition is similar to those for the Arrhenius relations. The following conductive mechanisms were proposed to account for the observed behaviors: the frequency-independent conductivity in the low frequency region is dominated by a long-distance transport of charge carriers via matrix-free carbon path, enhanced by an electric-field concentration effect; while the frequency-dependent conductivity in the high frequency region is dominated by a interfacial polarization process governed by charge carrier relaxation within the free-carbon phase. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

    Journal Title

    Acta Materialia

    Volume

    89

    Publication Date

    1-1-2015

    Document Type

    Article

    Language

    English

    First Page

    215

    Last Page

    224

    WOS Identifier

    WOS:000353249100021

    ISSN

    1359-6454

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