Le Journal de Physique IV 03 (1993) C5-307-C5-310
Dynamics of excitonic photoluminescence lineshape in narrow GaAs single quantum wellsK. FUJIWARA1, R. CINGOLANI2 and K. PLOOG3
1 Kyushu Institute of Technology, Tobata, Kitakyushu 804, Japan
2 University of Lecce, Strada per Arnesano, 73100 Lecce, Italy
3 Paul-Drude-Institut für Festkörperelektronik, 1086 Berlin, Germany
Dynamics of excitonic photoluminescence (PL) lineshape in narrow GaAs single quantum wells is investigated by measuring transient PL spectra in the picosecond time domains under direct excitation. We obtain distinct spectroscopie evidences for the exciton center-of-mass motion by drift-diffusion towards the local potential minima caused by the well-width fluctuations. That is, dynamical Stokes-shifts are directly observed. We find that inhomogeneous potential fluctuations in the quantum well plane result in asymmetry of the PL lineshape. The exciton trapped by the local minima formed due to the spatial inhomogeneity is directly evidenced by the lineshape analysis. From comparison with a case of spatially coherent quantum wells with growth island terraces, excellent correlation is obtained between the dynamical lineshape and the microscopic details of atomic-scale heterointerfaces.
© EDP Sciences 1993