Effect of a SiO2 layer on the thermal transport properties of <100> Si nanowires

A molecular dynamics study

Tomofumi Zushi, Kenji Ohmori, Keisaku Yamada, Takanobu Watanabe

    Research output: Contribution to journalArticle

    16 Citations (Scopus)

    Abstract

    The presence of a SiO2 layer on Si nanowires (SiNWs) has been found through molecular dynamics simulation to reduce their thermal conductivity (κ), with κ approaching the amorphous limit of Si as the oxide layer thickness is increased. Through analysis of the phonon energy dispersion and vibrational density of states (VDOS) spectrum, this decrease in κ was attributed to dispersionless vibrational states that appear in the low energy range below 4 THz as a result of the lattice vibration of Si atoms near the SiO2/Si interface. The SiO2 layer also induced a low-frequency tail in the VDOS spectrum, the length of which was more closely correlated to the reduction in κ than the frequency-integrated value of the VDOS spectrum. These findings provide a more refined explanation for the decrease in κ than has been previously observed, and contribute to providing a greater understanding of the anomalistic vibration near the interface that is critical to determining the heat conductivity in nanoscale materials.

    Original languageEnglish
    JournalPhysical Review B - Condensed Matter and Materials Physics
    Volume91
    Issue number11
    DOIs
    Publication statusPublished - 2015 Mar 18

    Fingerprint

    Transport properties
    Nanowires
    Molecular dynamics
    Thermal conductivity
    nanowires
    transport properties
    molecular dynamics
    Lattice vibrations
    Oxides
    lattice vibrations
    vibrational states
    Atoms
    Computer simulation
    thermal conductivity
    low frequencies
    heat
    vibration
    conductivity
    oxides
    energy

    ASJC Scopus subject areas

    • Condensed Matter Physics
    • Electronic, Optical and Magnetic Materials

    Cite this

    Effect of a SiO2 layer on the thermal transport properties of <100> Si nanowires : A molecular dynamics study. / Zushi, Tomofumi; Ohmori, Kenji; Yamada, Keisaku; Watanabe, Takanobu.

    In: Physical Review B - Condensed Matter and Materials Physics, Vol. 91, No. 11, 18.03.2015.

    Research output: Contribution to journalArticle

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