Vibrations and thermal transport in nanocrystalline silicon

    Authors

    A. Bodapati; P. K. Schelling; S. R. Phillpot;P. Keblinski

    Comments

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    Abbreviated Journal Title

    Phys. Rev. B

    Keywords

    YTTRIA-STABILIZED ZIRCONIA; MOLECULAR-DYNAMICS; GRAIN-BOUNDARIES; LOW; TEMPERATURES; CONDUCTIVITY; SOLIDS; SIMULATION; GLASSES; FILMS; RESISTANCE; Physics, Condensed Matter

    Abstract

    We use a combination of vibrational-mode analysis and molecular-dynamics simulations to study the effect of grain size on the nature of thermal vibrations, their localization, and their ability to carry heat in nanocrystalline silicon. Vibrational-mode analysis demonstrates that the vibrations that carry most of the heat in small-grain (less than or similar to 3 nm) structurally heterogeneous nanocrystalline silicon are almost identical in nature to those in homogeneous amorphous silicon, where the majority of the vibrations are delocalized and unpolarized. Consequently, the principal thermal conductivity mechanism in such a nanocrystalline material is the same as in the amorphous material. With increasing grain size, the vibrational modes become progressively more like that of a crystalline material; this is reflected in a crossover in the mechanism of thermal transport to that of a crystalline material.

    Journal Title

    Physical Review B

    Volume

    74

    Issue/Number

    24

    Publication Date

    1-1-2006

    Document Type

    Article

    Language

    English

    First Page

    11

    WOS Identifier

    WOS:000243195800050

    ISSN

    1098-0121

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