Density-Functional Study of the Si/SiO2 Interfaces in Short-Period Superlattices: Vibrational States and Raman Spectra

Raman spectroscopy has proven its effectiveness as a highly informative and sensitive method for the nondestructive analysis of layered nanostructures and their interfaces. However, there is a lack of information concerning the characteristic phonon modes and their activity in Si/SiO2 nanostructures...

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Bibliographic Details
Published inPhotonics Vol. 10; no. 8; p. 902
Main Authors Smirnov, Mikhail, Roginskii, Evgenii, Savin, Aleksandr, Oreshonkov, Aleksandr, Pankin, Dmitrii
Format Journal Article
LanguageEnglish
Published Basel MDPI AG 01.08.2023
Subjects
Approximation
Computer simulation
Cristobalite
Crystals
DFT modelling
Geometry
interface
Interfaces
Nanostructure
Nondestructive testing
Optimization
Parameter identification
Phonons
Raman spectra
Raman spectroscopy
Silicon
Silicon dioxide
Spectrum analysis
superlattice
Superlattices
Thickness
Vibrational states
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Summary:Raman spectroscopy has proven its effectiveness as a highly informative and sensitive method for the nondestructive analysis of layered nanostructures and their interfaces. However, there is a lack of information concerning the characteristic phonon modes and their activity in Si/SiO2 nanostructures. In order to overcome this problem, the phonon states and Raman spectra of several Si/SiO2 superlattices (SL) with layer thicknesses varied within 0.5–2 nm are studied using DFT-based computer modeling. Two types of structures with different interfaces between crystalline silicon and SiO2 cristobalite were studied. A relationship between the phonon states of heterosystems and the phonon modes of the initial crystals was established. Estimates of the parameters of deformation potentials are obtained, with the help of which the shifts of phonon frequencies caused by elastic strains in the materials of the SL layers are interpreted. The dependence of intense Raman lines on the SL structure has been studied. Several ways have been proposed to use this information, both for identifying the type of interface and for estimating the structural parameters. The obtained information will be useful for the spectroscopic characterization of the silicon/oxide interfaces.
ISSN:2304-6732
2304-6732
DOI:10.3390/photonics10080902