Femto-second photoreflectance spectroscopy of relaxation and tunneling processes in asymmetric GaAs/AlGaAs double quantum wells

The energy relaxation and the tunneling processes of electrons in an asymme tric double quantum well with mesoscopic size are investigated using the ti me-resolved photoreflectance spectroscopy with pump-probe method. It is fou nd that the time constants for planar dot structures depend on the shape of the dot. A possible origin of the variation is discussed in terms of the s cattering cross section near the potential wall with mesoscopic curvature. (C) 1999 Elsevier Science B.V. All rights reserved.