1. Ultrafast carrier dynamics and THz conductivity in epitaxial-grown LT-GaAs on silicon for development of THz photoconductive antenna detectors.
- Author
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Jessica Afalla, Gerald Catindig, Alexander De Los Reyes, Elizabeth Prieto, Maria Angela Faustino, Victor DC Vistro, Karl Cedric Gonzales, Hannah Bardolaza, Valynn Katrine Mag-usara, Horace Andrew Husay, Joselito Muldera, Neil Irvin Cabello, John Paul Ferrolino, Hideaki Kitahara, Armando Somintac, Arnel Salvador, Masahiko Tani, and Elmer Estacio
- Subjects
DETECTORS ,ANTENNAS (Electronics) ,ELECTRON traps ,PHOTOCONDUCTIVITY - Abstract
Carrier dynamics and photoconductivity in epitaxial-grown low-temperature GaAs on nominal and vicinal Si(1 0 0) substrates (‘LT-GaAs/Si’) were studied to predict their actual performance as THz photoconductive antenna (PCA) detectors. An optical-pump terahertz-probe technique was used to obtain the transmittance, carrier lifetime and photoconductivity of two LT-GaAs/Si samples, grown using different substrates and different growth protocols. The LT-GaAs grown on Si(1 0 0) substrate with a 4° tilt to 〈1 1 0〉 has better crystallinity, in agreement with other reports; while the LT-GaAs layer grown on nominal Si(1 0 0) substrate, though more structurally defective, has a much faster electron trapping time. Fabricated test PCAs with either dipole or bowtie geometries confirm the characterization results. The photoconductivity and carrier lifetime results manifest in the PCA performance, in responsivity, and in detection bandwidth. The prototypes’ sensitivities, bandwidths and dynamic ranges show that with some growth optimization, LT-GaAs/Si can be tailored to create economical, broadband THz detectors. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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