Excited states of two-dimensional hole gas at the Al0.5Ga0.5As/GaAs interface

Photoluminescence (PL and photoluminescence excitation (PLE) of modulation doped p-type A(1-x)Ga(x)As/GaAs heterostructures were studied at GaAs band gap region under the magnetic field up to 8 T in Faraday configuration. In the PL spectra a broad line. so called I-I-band, was visible. We observed a linear shift of this line with magnetic field. In the PLE spectra new line s. never reported before, were detected. They were slightly shifted by the magnetic field in a low-field regime and disappeared at B = 3 T. In our int erpretation the PLE lines originated from excitations of quasistationary in terface excitons whereas the H-band is the result of st free electron-confi ned hole recombination. Theoretical data are in good agreement with experim ental results. (C) 2000 Elsevier Science B.V. All rights reserved.