Espalhamento Raman em heteroestruturas semicondutoras de Si/Ge

AUTOR(ES)
DATA DE PUBLICAÇÃO

1995

RESUMO

We have used Raman spectroscopy to study the lattice dynamics of Ge/Si semiconductor heterostructures, both experimentally and theoretically. The study was performed in a broad spectral range (from 2 cm-1 up to 600 cm-1), which includes the acoustical folded phonons, interfaces phonons, and confined optical phonons. We have used several experimental systems: a standard, a high resolution, and a micro-Raman setup. Theoretically, we have applied a one-dimensional linear-chain model with second-neighbor interactions to obtain the vibrational modes and a bond-polarizability model to simulate the Raman spectra. A phenomenological analysis allows us to verify the presence of large scale roughness (terraces) in the interfaces of our samples. Resonant Raman measurements were also performed for the optical phonons of our microstructures. Quantitative analysis of the resonant-Raman cross-section of the peak originating in Ge-Ge confined vibrations allows us to single out optical transitions of excitons confined within each terrace. This analysis favours our previous interpretation of this transition, which relates it to the E1-transitions of bulk Ge

ASSUNTO(S)

germanio silicio semicondutores

ACESSO AO ARTIGO

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