Ultrafast carrier dynamics in Au∕GaAs interfaces studied by terahertz emission spectroscopy

Abstract

The measurements of optically generated terahertz emission from Au∕GaAs interfaces are investigated in detail. We observe that, under high laser power excitation, terahertz signals from bare GaAs wafers and Au∕GaAs samples exhibit an opposite polarity. The polarity-flip behaviors are also observed in temperature-dependent and femtosecond pump-generation studies of the Au∕GaAs interfaces.