Abstract
Ultra-highly-sensitive far-infrared detectors are developed for potential application to astronomy. The detectors exploit a novel mechanism called Charge Sensitive Infrared Phototransistors (CSIPs), in which an upper quantum well (QW) in GaAs/AlGaAs double QW structures is positively charged up by photo-excitation via inter-subband transition. This causes the conductance of the lower QW channel to increase. The device is effectively a phototransistor, in which the upper QW serves as a photo-sensitive gate to the source-drain channel provided by the lower QW. Resultant extraordinary high photoconductive gain makes CSIPs so sensitive as to detect single photons. CSIPs are well established in the mid-infrared (\(\lambda \) = 12–20 \(\upmu \)m), achieving noise equivalent power around 1.9 \(\times \) 10\(^{-19}\) W/Hz\(^{1/2}\) with a quantum efficiency of 7 %. CSIPs have been demonstrated to work in longer wavelengths up to 45 \(\upmu \)m, but the sensitivity was not as high as in the shorter wavelengths, probably due to lower quantum efficiency. Reported here is a remarkable improvement in the performance of longer wavelength CSIPs (45 \(\upmu \)m), achieved primarily by optimizing the do** concentration in the upper QW. This work indicates that longer wavelength CSIPs are promising detectors for the astronomical application.
![](http://media.springernature.com/m312/springer-static/image/art%3A10.1007%2Fs10909-014-1140-6/MediaObjects/10909_2014_1140_Fig1_HTML.gif)
![](http://media.springernature.com/m312/springer-static/image/art%3A10.1007%2Fs10909-014-1140-6/MediaObjects/10909_2014_1140_Fig2_HTML.gif)
![](http://media.springernature.com/m312/springer-static/image/art%3A10.1007%2Fs10909-014-1140-6/MediaObjects/10909_2014_1140_Fig3_HTML.gif)
Similar content being viewed by others
References
M. Kawada, H. Baba, P.D. Barthel et al., PASJ 59, 389 (2007)
V. Revéret, P. André, M. Talvard et al., J. Low Temp. Phys. 151, 32 (2008)
P. Khosropanah, R. Hijmering, M. Ridder et al., Proc. SPIE 8452, 845209 (2012)
S. Doyle, J. Naylon, P. Mauskopf et al., Proc. SPIE 7020, 70200T (2008)
S. Komiyama, IEEE J. Sel. Top. Quant. 17, 1 (2011)
P. Nickels, S. Matsuda, T. Ueda, Z. An, S. Komiyama, IEEE J. Quant. Electron. 43, 3 (2010)
Z. An, T. Ueda, K. Hirakawa, S. Komiyama, IEEE Trans. Electron Dev. 54, 7 (2007)
T. Ueda, Y. Soh, N. Nagai, S. Komiyama, H. Kubota, Jpn. J. Appl. Phys. 50, 020208 (2011)
T. Ueda, Z. An, K. Hirakawa, S. Komiyama, J. Appl. Phys. 103, 093109 (2008)
Y. Kajihara, K. Kosaka, S. Komiyama, Opt. Express 19, 8 (2011)
Z. Wang, S. Komiyama, T. Ueda, M. Patrashin, I. Hosako, J. Appl. Phys. 107, 094508 (2010)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Nihei, R., Komiyama, S., Kawada, M. et al. Development of Charge Sensitive Infrared Phototransistors for the Far-Infrared Wavelength. J Low Temp Phys 176, 261–266 (2014). https://doi.org/10.1007/s10909-014-1140-6
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10909-014-1140-6