Ov. Volkov et al., EXCITONS AND EXCITONIC COMPLEXES IN GAAS ALGAAS QUANTUM-WELLS WITH A LOW-DENSITY QUASI-2-DIMENSIONAL ELECTRON AND HOLE CHANNEL/, JETP letters, 67(9), 1998, pp. 744-750
The recombination spectra of excitons and excitonic complexes in undop
ed GaAs/AlGaAs single quantum wells are investigated. It is shown on t
he basis of a study of the magnetic-field dependence of the emission s
pectra and the degree of optical orientation in zero magnetic field an
d on the basis of electrooptic measurements that not only the density
but also the sign of the charge carriers in a well depend strongly on
the photoexcitation energy. It is shown on the basis of a comparative
analysis of the spin splitting of the recombination lines of free and
bound excitons that the recombination line which was attributed earlie
r to a positively charged exciton corresponds to the recombination of
an exciton bound on a neutral acceptor. (C) 1998 American Institute of
Physics. [S0021-3640(98)01909-4].