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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.