Properties of deep levels and photorefractive effect in GaAs/AlGaAs multiple quantum wells grown in low temperature

We report on the properties of GaAs/AlGaAs multiple quantum wells grown at medium temperature range 300-400 degreesC. The samples exhibit both of shar p exciton absorption and ultrafast carrier lifetime, which are suitable as photorefractive devices. Photoluminescence, absorption spectroscopy, optica l transient current spectroscopy and pump-probe technique were used to char acterize the materials grown on GaAs (0 0 1) on-axis or miscut substrates. Using a YAG:Nd laser as a pump source, the quenchable characteristics of EL 2-like defects were observed in electroabsorption for the first rime. By op timizing growth parameters and device structure, the transient diffraction efficiency approaches 1.2% and 4.5% in non-degeneration four-wave mixing un der Frantz-Keldysh and Stark geometry, respectively. (C) 2001 Elsevier Scie nce B.V. All rights reserved.