Inter-acting separately confined two-dimensional electron and hole gases: magnetic field dependence of the circularly polarized photoluminescence

We present a study of interacting, separately confined electron and hole layers that are photoexcited in undoped GaAs/AlAs mixed types I-II quantum wells. The low-temperature interband photoluminescence spectra and circularly polarized integrated intensity were studied as a function of a perpendicularly applied magnetic field (B less than or equal to 7 T) and 2DEG density (n(e) less than or equal to 8 x 10(11) cm(-2)). The observed rich structure of the lowest Landau index magnetoexcitons and the strong intensity oscillations at integral filling factors are interpreted as due to cooperative 2DEG-2DHG transitions and, possibly, to the formation of weakly bound inter-layer excitons. (C) 2000 Elsevier Science B.V. All rights reserved.