Highly efficient photoconductive antennas using optimum low-temperature-grown GaAs layers and Si substrates

We have improved the efficiency of photoconductive antennas (PCAs) using low-temperature-grown GaAs (LT-GaAs). We found that the physical properties of LT-GaAs photoconductive layers greatly affect the generation and detection characteristics of terahertz (THz) waves. In THz generation, high photoex...

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Bibliographic Details
Published in:Japanese Journal of Applied Physics 2014-03, Vol.53 (3), p.32201-1-032201-7
Main Authors: Kamo, Yoshihiko, Kitazawa, Shogo, Ohshima, Seiro, Hosoda, Yasuo
Format: Article
Language:English
Subjects:
Antennas
Dynamic range
Feasibility
Gallium arsenide
Gallium arsenides
Noise levels
Optimization
Physical properties
Silicon substrates
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Summary:We have improved the efficiency of photoconductive antennas (PCAs) using low-temperature-grown GaAs (LT-GaAs). We found that the physical properties of LT-GaAs photoconductive layers greatly affect the generation and detection characteristics of terahertz (THz) waves. In THz generation, high photoexcited carrier mobility and the presence of a few As clusters in the LT-GaAs are two important factors. In detection, short carrier lifetime and the absence of a polycrystalline structure in the LT-GaAs are significant factors. By optimizing these physical properties, we improved the total dynamic range of THz generation and detection by 15 dB over that obtained by conventional commercially available PCAs. In addition, we replaced the semi-insulating GaAs (SI-GaAs) substrate with a Si substrate, which has a low absorption in the THz region. We proposed a new idea of including a highly insulating Al0.5Ga0.5As buffer layer on the Si substrate. Finally, we confirmed the feasibility of manufacturing PCAs using Si substrates.
ISSN:0021-4922
1347-4065
DOI:10.7567/JJAP.53.032201