Nonlinear IR and THz Spectroscopy of Semiconductor Nanowires

Abstract

We report nonlinear charge-carrier response in GaAs/InGaAs core/shell nanowires that are driven by intense THz pulses. In the first experiment, half-cycle THz pulses emitted from an organic DSTMS crystal lead to a red-shift of the plasmon peak indicating intervalley transfer of the electrons. In the second experiment, a single, highly electron doped nanowire is investigated by scattering near-field infrared microscopy using intense free-electron laser (FEL) pulses. Here the observed red shift of the mid-infrared plasma resonance depends on the pulse energy and can be explained by heating the electron system in the nonparabolic conduction band.