NEAR RESONANT RAMAN SCATTERING FROM GaAs/AlAs SUPERLATTICES
GaAs/AlAs超晶格的近共振喇曼散射研究

This article presents the results of near resonant Raman scattering measurement of GaAs/ AlAs superlattices at room temperature. A strong enhancement of GaAs LO phonon even modes resulted owing to dipole allowed Fr?hlich interaction in superlattices. Similar to the previous results, the LO phonon even modes in polarized configuration is observed. In contrast to the previous works, however, what we observed in depolarized configuration is the LO phonon odd modes instead of even modes. And it is confirmed that the selection rules of near resonant Raman scattering from LO phonons in this kind of superlattices is the same as that of off resonant scattering. From the second-order Raman scattering, it is confirmed that polarized second-order Raman scattering spectra consist of overtone and combinations of two even modes and depolarized second-order Raman scattering spectra consist of combinations of an even mode and an odd mode. Our experimental results coincide with the predictions using recently developed Huang-Zhu model. A brief discussion on interface modes and their combination with confined modes are also presented.