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HL: Fachverband Halbleiterphysik
HL 59: THz and MIR physics in semiconductors
HL 59.7: Vortrag
Donnerstag, 19. März 2020, 11:30–11:45, POT 151
Nonlinear charge transport in GaAs/InGaAs core/shell nanowires at terahertz frequencies — •Rakesh Rana1, Leila Balaghi1,2, Ivan Fotev1,2, Harald Schneider1, Manfred Helm1,2, Emmanouil Dimakis1, and Alexej Pashkin1 — 1Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Germany — 2Center for advancing electronics Dresden (cfaed), Technische Universität Dresden, 01062 Dresden, Germany
We report the high-field transport and the plasmonic response of GaAs/InGaAs core/shell nanowires (NWs) by employing optical pump - terahertz probe spectroscopy with peak electric fields up to 2 MV/cm. The plasmon mode experiences a systematic redshift and a suppression of the spectral weight with the increase of the driving THz field. The electron mobility exhibits a threshold-like behavior and starts to decrease for peak electric fields above 0.7MV/cm. This phenomenon is assigned to the increase of the effective mass due to the intervalley scattering in InGaAs. Our analysis shows the absence of the carrier multiplication in NWs even for fields beyond 1 MV/cm, in contrast to bulk InGaAs. Remarkably, the linear dependence between the plasmon spectral weight and the square of its frequency breaks down in the high field regime. Our theoretical modeling demonstrates that this behavior stems from a non-uniform distribution of the local electric field inside the NW leading to intervalley scattering mainly in its middle part. The discovered properties prove the potential of NWs for terahertz band nanoelectronics.