ISSN:
1436-5073
Keywords:
FTIR
;
semiconductors
;
lattice vibrations
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract A home-made slow-scan Fourier spectrometer was adapted in the far infrared (10–100 cm−1) to investigate strained-layer Si/Si0.5Ge0.5 superlattices (=SLs) with modulation periodsD=120 Å, 40 Å at liquid helium temperature. The small variations of reflectivity (≤10−3) were detected against the large background by modulating the temperature of the sample using a chopped near infrared light emitting diode. The resulting change of sample temperature causes a variable population of the lowest acoustic phonon branch to largerq-values, and a large fraction of the zone folded phonon dispersion (∥q∥≤π/D) can be measured by observing difference phonon processes. The measurements outline important SL-properties (modulation periods, phonon dispersion, interface quality and strain effects). X-ray diffraction analysis confirms the FTIR-results.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01205920
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