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Raman scattering studies of Ge/Si islands under hydrostatic pressure
Author(s) -
Teo K. L.,
Shen Z. X.,
Schmidt O. G.
Publication year - 2004
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200405239
Subject(s) - hydrostatic pressure , raman spectroscopy , raman scattering , phonon , molecular beam epitaxy , resonance (particle physics) , intensity (physics) , materials science , pressure coefficient , condensed matter physics , ambient pressure , chemistry , molecular physics , atomic physics , epitaxy , optics , nanotechnology , physics , thermodynamics , layer (electronics)
Raman scattering under hydrostatic pressure is used to investigate the phonon modes of self‐assembled Ge islands grown by solid source molecular beam epitaxy. Our results show that the overlapping spectra of the Ge–Ge phonon and Si 2TA modes occur around 304 cm –1 at ambient pressure can be resolved at relatively low pressure of about 3 kbar. The mode Grüneisen parameter of the Ge–Ge phonon mode in quantum dot is found to be γ = 0.84 ± 0.01. The normalized Raman intensity profiles of Ge–Ge mode, exhibits a resonance enhancement peak at 2.37 eV. The pressure coefficient of this resonating electronic transition is ∼2.7 ± 0.5 meV/kbar, which is significantly smaller than the pressure shift of the E 1 transition in bulk Ge. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)