TY  - JOUR
AU  - Zhang, Jie
AU  - Mikulics, Martin
AU  - Adam, Roman
AU  - Grützmacher, Detlev
AU  - Sobolewski, Roman
TI  - Generation of THz transients by photoexcited single-crystal GaAs meso-structures
JO  - Applied physics / B
VL  - 113
IS  - 3
SN  - 1432-0649
CY  - Berlin
PB  - Springer
M1  - FZJ-2014-00596
SP  - 339 - 344
PY  - 2013
AB  - We report a sub-picosecond photoresponse and THz transient generation of GaAs single-crystal mesoscopic platelets excited by femtosecond optical pulses. Our structures were fabricated by a top-down technique, by patterning an epitaxial, 500-nm-thick GaAs film grown on top of an AlAs sacrificial layer and then transferring the resulting etched away 10 9 20-lm2 platelets onto an MgO substrate using a micropipette. The freestanding GaAs devices, incorporated into an Au coplanar strip line, exhibited extremely low dark currents and *0.4 % detection efficiency at 10 V bias. The all-optical, pump–probe carrier dynamics analysis showed that, for 800-nmwavelengthexcitation, the intrinsic relaxation of photocarriersfeatured a 310-fs-wide transient with a 290 fs falltime. We have also carried out a femtosecond, timeresolved electro-optic characterization of our devices and recorded along the transmission line the electrical transients as short as *600 fs, when the platelet was excited by a train of 100-fs-wide, 800-nm-wavelength optical laser pulses. The platelets have been also demonstrated to be very efficient generators of free-space propagating THz transients with the spectral bandwidth exceeding 2 THz. The presented performance of the epitaxial, freestanding GaAs meso-structured photodevices makes them uniquely suitable for THz-frequency optoelectronic applications, ranging from ultrafast photodetectors to THz-bandwidth optical-to-electrical transducers and photomixers.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000328054500005
DO  - DOI:10.1007/s00340-013-5495-1
UR  - https://juser.fz-juelich.de/record/150542
ER  -