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HL: Halbleiterphysik
HL 9: Heterostrukturen
HL 9.8: Vortrag
Montag, 23. März 1998, 17:45–18:00, H17
Raman and Infrared Spectroscopical Investigation of
the Optical Vibrational Modes in GaSb/AlSb Superlattices — •Alexander Milekhin1, Thomas Werninghaus2, Dietrich R.T. Zahn2, Yuri Yanovskii1, Valeri Preobrazhenskii1, Boris Semyagin1, and Anton Gutakovskii1 — 1Institute of Semiconductor Physics, 630090, Novosibirsk, Russia — 2Institut für Physik, Professur für Halbleiterphysik, TU Chemnitz, D-09107 Chemnitz
The vibrational spectrum of ultra-thin layer high quality GaSb/AlSb
superlattices (SLs) was investigated in details by Infrared (IR) and Raman
spectroscopies. The periodicity is validated by cross-sectional transmission
electron microscopy. From the optical response of the SLs the effect of the
confinement of the transverse and longitudinal optical phonons in both layer
material types was studied. Due to this confinement effect the optical phonon
modes far away from the center of the Brillouin zone can be probed. As a
result, the dispersion of the optical phonons of the GaSb and the AlSb
obtained from the analysis of the Raman and IR spectra are in a very good
accordance with the theoretical data and results of neutron scattering
experiments. The intermixture of atoms at the interfaces of the SLs was
probed by the appearance of the GaSb-like and AlSb-like alloying modes. The
second-order Raman scattering by the combination of interface, longitudinal,
and transverse optical phonons of GaSb and AlSb was also investigated
experimentally.