Ultrafast Dynamics of Interfacial Electric Fields in Semiconductor Heterostructures Monitored by Pump-Probe Second Harmonic Generation

TL;DR

This study uses pump-probe second harmonic generation to observe ultrafast interfacial electric field dynamics in semiconductor heterostructures, revealing carrier redistribution and band hybridization effects.

Contribution

First measurement of ultrafast interfacial electric field dynamics in semiconductor multilayers using SHG, highlighting carrier redistribution and band hybridization effects.

Findings

Identification of multiple stages of carrier redistribution

Detection of enhanced electric fields due to band hybridization

Real-time monitoring of interfacial electric field evolution

Abstract

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.