Ultrafast Dynamics of Interfacial Electric Fields in Semiconductor   Heterostructures Monitored by Pump-Probe Second Harmonic Generation
  We report first measurements of the ultrafast dynamics of interfacial electric fields in semiconductor multilayers using pump-probe second harmonic generation (SHG). A pump beam was tuned to excite carriers in all layers of GaAs/GaSb and GaAs/GaSb/InAs heterostructures. Further carrier dynamics manifests itself via electric fields created by by charge separation at interfaces. The evolution of interfacial fields is monitored by a probe beam through the eletric-field-induced SHG signal. We distinguish between several stages of dynamics originating from redistribution of carriers between the layers. We also find a strong enhancement of the induced electric field caused by hybridization of the conduction and valence bands at the GaSb/InAs interface. 
Yu. D. Glinka, T. V. Shahbazyan, I. E. Perakis, N. H. Tolk, X. Liu, Y.   Sasaki and J. K. Furdyna