Thickness-Dependent Phonon Renormalization and Enhanced Raman Scattering in Ultrathin Silicon Nanomembranes

Seonwoo Lee, Kangwon Kim, Krishna P. Dhakal, Hyunmin Kim, Won Seok Yun, Jaedong Lee, Hyeonsik Cheong, Jong Hyun Ahn

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

We report on the thickness-dependent Raman spectroscopy of ultrathin silicon (Si) nanomembranes (NMs), whose thicknesses range from 2 to 18 nm, using several excitation energies. We observe that the Raman intensity depends on the thickness and the excitation energy due to the combined effects of interference and resonance from the band-structure modulation. Furthermore, confined acoustic phonon modes in the ultrathin Si NMs were observed in ultralow-frequency Raman spectra, and strong thickness dependence was observed near the quantum limit, which was explained by calculations based on a photoelastic model. Our results provide a reliable method with which to accurately determine the thickness of Si NMs with thicknesses of less than a few nanometers.

Original languageEnglish
Pages (from-to)7744-7750
Number of pages7
JournalNano letters
Volume17
Issue number12
DOIs
Publication statusPublished - 2017 Dec 13

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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