Le Journal de Physique IV 03 (1993) C5-237-C5-240
Γ-X mixing in type-II GaAs/AlAs short period superlatticesV. VOLIOTIS1, R. GROUSSON1, P. LAVALLARD1, E.L. IVCHENKO2, A.A. KISELEV2 and R. PLANEL3
1 Groupe de Physique des Solides, Universités Paris VI et Paris VII, URA 17 du CNRS, 2 place Jussieu, 75251 Paris cedex 05, France
2 A.F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
3 Laboratoire de Microstructures et de Microélectronique, UPR 20 du CNRS, 196 av. Henri Ravera, 92220 Bagneux, France
We have measured the absolute absorption coefficient of optical transitions in type-II short period GaAs/AlAs superlattices, on a broad spectral range, at low temperature. The transmission experiments have been performed in a waveguiding configuration. Photoluminescence excitation experiments show as well the characteristics of the pseudodirect HH1-Xz excitonic transition. Theoretical calculations of the effective dielectric tensor and absorption coefficient in the vicinity of the exciton resonance frequency are presented, taking explicitely into account the Γ-X mixing of electronic states at heteroboundaries. From comparison between the experimental and theoretical values of the absorption coefficients, we have deduced a value of the Γ-X coupling coefficient for the studied superlattices.
© EDP Sciences 1993