Size effects in near-ultraviolet Raman spectra of few-nanometer-thick silicon-on-insulator nanofilms

Vladimir Poborchii, Yukinori Morita, Tetsuya Tada, Pavel I. Geshev, Zhandos N. Utegulov, Alexey Volkov

    Research output: Contribution to journalArticle

    1 Citation (Scopus)

    Abstract

    We have fabricated Si-on-insulator (SOI) layers with a thickness h1 of a few nanometers and examined them by Raman spectroscopy with 363.8 nm excitation. We have found that phonon and electron confinement play important roles in SOI with h1 <10 nm. We have confirmed that the first-order longitudinal optical phonon Raman band displays size-induced major homogeneous broadening due to phonon lifetime reduction as well as minor inhomogeneous broadening due to wave vector relaxation (WVR), both kinds of broadening being independent of temperature. Due to WVR, transverse acoustic (TA) phonons become Raman-active and give rise to a broad band in the range of 100-200 cm-1. Another broad band appeared at 200-400 cm-1 in the spectrum of SOI is attributed to the superposition of 1st order Raman scattering on longitudinal acoustic phonons and 2nd order scattering on TA phonons. Suppression of resonance-assisted 2-nd order Raman bands in SOI spectra is explained by the electron-confinement-induced direct band gap enlargement compared to bulk Si, which is confirmed by SOI reflection spectra.

    Original languageEnglish
    Article number154302
    JournalJournal of Applied Physics
    Volume119
    Issue number15
    DOIs
    Publication statusPublished - Apr 21 2016

    Fingerprint

    ultraviolet spectra
    insulators
    Raman spectra
    silicon
    phonons
    acoustics
    broadband
    electrons
    Raman spectroscopy
    retarding
    life (durability)
    scattering
    excitation
    temperature

    ASJC Scopus subject areas

    • Physics and Astronomy(all)

    Cite this

    Size effects in near-ultraviolet Raman spectra of few-nanometer-thick silicon-on-insulator nanofilms. / Poborchii, Vladimir; Morita, Yukinori; Tada, Tetsuya; Geshev, Pavel I.; Utegulov, Zhandos N.; Volkov, Alexey.

    In: Journal of Applied Physics, Vol. 119, No. 15, 154302, 21.04.2016.

    Research output: Contribution to journalArticle

    Poborchii, Vladimir ; Morita, Yukinori ; Tada, Tetsuya ; Geshev, Pavel I. ; Utegulov, Zhandos N. ; Volkov, Alexey. / Size effects in near-ultraviolet Raman spectra of few-nanometer-thick silicon-on-insulator nanofilms. In: Journal of Applied Physics. 2016 ; Vol. 119, No. 15.
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    AU - Geshev, Pavel I.

    AU - Utegulov, Zhandos N.

    AU - Volkov, Alexey

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