Novel exciton-like optical transitions in AlGaAs/GaAs single heterojunctions

Abstract The photoconductivity and photoluminescence spectra measured on MBE-grown modulation-doped AlGaAs/GaAs heterojunctions show a novel structure consisting of several sharp excitonic-like peaks extended up to ≈ 30 meV above the bulk GaAs exciton recombination energy. Their two-dimensional (2D) nature has been confirmed by an external magnetic field angle dependence. The two proposed models assume localized centers of donor and acceptor nature concentrated at or near the interface.