相关论文: Spatially resolved ultrafast transport current in …
Time-resolved electrical spin transport is used to generate and probe spin currents in GaAs electrically. We use high bandwidth current pulses to inject phase-coherent spin packets from Fe into n-GaAs. By means of time-resolved Faraday…
A microscopic approach that is based on the multisubband semiconductor Bloch equations formulated in the basis of a 14-band ${\mathbf k} \cdot {\mathbf p}$ model is employed to compute the temporal dynamics of photocurrents in GaAs quantum…
We probe the electron transport properties in the shell of GaAs/In0.2Ga0.8As core/shell nanowires at high electric fields using optical pump / THz probe spectroscopy with broadband THz pulses and peak electric fields up to 0.6 MV/cm. The…
The ambipolar carrier diffusion in bulk GaAs is studied by using an ultrafast pump-probe technique with a high spatial resolution. Carriers with a point-like spatial profile are excited by a tightly focused pump laser pulse. The…
Shift current---a photocurrent induced by light irradiating noncentrosymmetric materials in the absence of any bias voltage or built-in electric field---is one of the mechanisms of the so-called bulk photovoltaic effect. It has been…
The authors study the ultrafast switching-on and -off of planar GaAs/AlAs microcavities. Up to 0.8% refractive index changes are achieved by optically exciting free carriers at 1720 nm and a pulse energy of 1.8 micro Joules. The cavity…
Transient magnetotransport of two-dimensional electrons with partially-inverted distribution excited by an ultrashort optical pulse is studied theoretically. The time-dependent photoconductivity is calculated for GaAs-based quantum wells by…
Ultrafast photocurrent measurements are performed on individual carbon nanotube PN junction photodiodes. The photocurrent response to sub-picosecond pulses separated by a variable time delay {\Delta}t shows strong photocurrent suppression…
In condensed matter, scattering processes determine the transport of charge carriers. In case of heterostructures, interfaces determine many dynamic properties like charge transfer and transport and spin current dynamics. Here we discuss…
Many active particles, both of biological and synthetic origin, can have a light controllable propulsion speed, a property that in biology is commonly referred to as photokinesis. Here we investigate directed transport of photokinetic…
It is demonstrated that the non-instantaneous response of the optically induced coherent polarization tremendously influences the real-space shift of electronic charges in semiconductors. The possibility to coherently control this…
We have investigated the photocarrier charge transport in n-type metallic GaAs nanowires (~ 10^17 cm^-3 doping level), grown by hydride vapor phase epitaxy (HVPE) on Si(111) substrates. Analysis of the luminescence intensity spatial…
To clarify the ultrafast temporal interplay of the different photocurrent mechanisms occurring in single InAs-nanowire-based circuits, an on-chip photocurrent pump-probe spectroscopy based on coplanar striplines was utilized. The data are…
The perturbation of a semiconductor from the thermodynamic equilibrium often leads to the display of nonlinear dynamics and formation of spatiotemporal patterns due to the spontaneous generation of competing processes. Here, we describe the…
We measure fast carrier decay rates (6 ps) in GaAs photonic crystal cavities with resonances near the GaAs bandgap energy at room temperature using a pump-probe measurement. Carriers generated via photoexcitation using an above-band…
We induce ultrafast photocurrents in a GaAs crystal exposed to a magnetic field by optical femtosecond excitation. The magneto-photocurrents are studied by time-resolved detection of the simultaneously emitted THz radiation. We find that…
The time-of-flight method is a fundamental approach for characterizing the transport properties of semiconductors. Recently, the transient photocurrent and optical absorption kinetics have been simultaneously measured for thin films;…
We perform time- and angle-resolved photoelectron spectroscopy on p-type GaAs(110). We observe an optically excited population in the conduction band, from which the time scales of intraband relaxation and surface photovoltage decay are…
We report here a general theory describing photoelectron transportation dynamics in GaAs semiconductor photocathodes. Gradient doping is incorporated in the model through the inclusion of directional carrier drift. The time-evolution of…
We induce ultrafast magneto-photocurrents in a GaAs crystal employing interband excitation with femtosecond laser pulses at room temperature and non-invasively separate surface and bulk contributions to the overall current response. The…