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Electronics and FluidicsElectrical and Electronic Equipment

Spatial Pattern Formation of Optically Excited Carriers in Photoconductive THz Antennas

Authors: M. Bieler; G. Hein; K. Pierz; U. Siegner; M. Koch; PHYSIKALISCH-TECHNISCHE BUNDESANSTALT BRAUNSCHWEIG (GERMANY)
Abstract:
We have investigated the role of spatio-temporal carrier dynamics in photoconductive THz antennas. To this end, the photoluminescence from a GaAs/AlGaAs quantum well has been spatially resolved after femtosecond laser excitation for different electric bias fields applied in the plane of the well. The photoluminescence patterns demonstrate substantially different electron-hole dynamics across the excitation laser spot. The density dependence of screening combines with the lateral variation of the carrier density to produce the observed effects. The experimental data are compared to a self-consistent calculation of the drift-diffusion equation for electrons and holes and Poisson's equation for the electric field in both space and time. Our results prove that the spatial variation of the carrier dynamics should be taken into account for further optimization of THz antennas.

Limitations: APPROVED FOR PUBLIC RELEASE
Pages: 3
Report Date: 29 SEP 2000
Contract Number: N0001340011104
Report Number: P697110
Keywords relating to this report:
ALUMINUM GALLIUM ARSENIDES
BIAS
CURRENT DENSITY
DIPOLE ANTENNAS
ELECTRIC FIELDS
EXCITATION
EXPERIMENTAL DATA
FAR INFRARED RADIATION
FREQUENCY BANDS
GALLIUM ARSENIDES
HOLES(ELECTRON DEFICIENCIES)
LASER SPOTS
LASER SPOTSZ
LASER SPOTSZQUANTUM WELLS
OPTICAL PROPERTIES
OPTIMIZATION
PHOTOCONDUCTORS
PHOTOLUMINESCENCE
POISSON EQUATION
QUANTUM WELLS
SEMICONDUCTOR DEVICES
SPATIAL DISTRIBUTION
SYMPOSIA
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