Le Journal de Physique IV 03 (1993) C5-343-C5-346
Exciton states in GaAs/AlGaAs Bragg confining structures studied by resonant Raman scatteringM. ZAHLER1, E. COHEN1, J. SALZMAN1, E. LINDER1 and L.N. PFEIFFER2
1 Solid State Institute, Technion- Israel Institute of Technology, Haifa 32000, Israel
2 AT[MATH]T Bell Laboratories, Murray Hill, NJ 07974, U.S.A.
We report on the study of the low temperature resonant Raman scattering (RRS) in GaAs/Al0.32,Ga0.68As Bragg confining structures (BCS). The LO-phonon RRS is observed in the spectral range of the (eB : hhB) and (eB : lhB) Bragg confined excitons. The RRS profiles show an outgoing beam resonance that is much stronger than the incoming beam resonance. These profiles are analyzed by a model in which the exciton dimensionality affects the in-plane excitonic dispersion and the Fröhlich interaction dependence on the phonon wavevector. The exciton scattering, in its translational motion, is assumed to be due to heavy point defects (short range potential fluctuations). Detailed calculations of the RRS profiles result in excellent agreement with the observed spectra. From them we conclude that the Bragg confined (eB : hhB) exciton is approximately 2-dimensional.
© EDP Sciences 1993