Study of Extended Electrically Active Defects in Heterostructures Based on (Ga,Mn)As/(In,Ga)As by Electron Beam-Induced Current and Deep-Level Transient Spectroscopy

Resumo

Electrically active defects in (Ga,Mn)As/(In,Ga)As/GaAs heteroepitaxial structures, both in GaAs and InGaAs epitaxial layers and near the interface, are investigated by induced current and relaxation spectroscopy. On the images obtained by the induced-current method, extended defects are observed not only near the GaAs–InGaAs interface but also throughout the entire volume of the InGaAs layer, almost to its upper boundary. Two deep levels (at E_V of +0.50 and +0.65 eV), which could be related to extended defects, are revealed in the lower part of the band gap in the structures under study. A possible relation between deep levels and extended recombination-active defects detected by the electron-beam-induced current method is discussed.