2024-03-28T21:35:49Zhttps://gredos.usal.es/oai/requestoai:gredos.usal.es:10366/1471412022-02-07T15:41:45Zcom_10366_4531com_10366_4512com_10366_3823col_10366_4532
Influence of Laser Modulation Frequency on the Performance of Terahertz Photoconductive Switches on Semi-Insulating GaAs Exhibiting Negative Differential Conductance
Paz-Martinez, Gaudencio
Trevino-Palacios, Carlos Gerardo
Molina-Reyes, Joel
Romero-Moran, Alejandra
Cervantes-Garcia, Eric
Mateos López, Javier
González Sánchez, Tomás
Negative differential conductance (NDC)
Photoconductive switch
Terahertz time-domain spectroscopy (THz-TDS)
2202.01 Conductividad
2209.21 Espectroscopia
2203 Electrónica
[EN]In typical terahertz time-domain spectroscopy systems, the use of the lock-in technique is necessary because of the low current induced at the receiver so that the laser pump beam must be modulated (chopped) at a frequency much lower than the laser repetition rate. This work shows that, in the case of semi-insulating GaAs (SI-GaAs) antennas, this modulation has an important effect on the antenna current and consequently, on the radiated electromagnetic pulse. There exists a threshold bias (whose value depends on the chopping frequency) where an abrupt increase in the current and consequently, in the terahertz emission takes place. The calculated energy of the pulse below and above the threshold shows that the energy doubles. The exact bias voltage at which this occurs changes with the laser modulation frequency when this is below 350 Hz, but at higher frequencies, the threshold remains almost constant. The experiments show that the responsibility for this behavior is the S-shape negative differential conductance exhibited by SI-GaAs originated by a slow field-enhanced charge trapping mechanism, which is also an important source of noise at the receiver of the system.
SpanishMINECO and FEDER under Project TEC2017-83910-R and in Junta de Castilla y León and FEDER
under Project SA254P18
2021-09-13T09:33:29Z
2021-09-13T09:33:29Z
2021
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
Paz-Martínez, G. et al. (2021). Influence of Laser Modulation Frequency on the Performance of Terahertz Photoconductive Switches on Semi-Insulating GaAs Exhibiting Negative Differential Conductance. IEEE Transactions on Terahertz Science and Technology, 11 (5), pp. 591-597. doi: 10.1109/TTHZ.2021.3083926.
2156-342X
http://hdl.handle.net/10366/147141
10.1109/TTHZ.2021.3083926
2156-3446
eng
https: //doi.org/10.1109/TTHZ.2021.3083926.
SA254P18
TEC2017-83910-R
Attribution-NonCommercial-NoDerivatives 4.0 Internacional
http://creativecommons.org/licenses/by-nc-nd/4.0/
info:eu-repo/semantics/openAccess
application/pdf
IEEE
https://gredos.usal.es/bitstream/10366/147141/5/THzSC-2021.pdf.jpg
Hispana
TEXT
http://creativecommons.org/licenses/by-nc-nd/4.0/
Gredos. Repositorio Documental de la Universidad de Salamanca
http://hdl.handle.net/10366/147141