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In conclusion, transistors processed from GaAs/GaAlAs Figure 10. a frequency of the resonant detection of the and GaInAs/GaAlAs heterostructures were investigated by group A, B and C transistors, as a function of the swing voltage.

magnetotransport measurements in order to characterize b quality factor corresponding to a frequency of the resonant their applicability as resonant tuneable detectors of THz detection, plotted in a), for the group A, B and C transistors.

radiation. We showed how the electron mobility in the transistor can be evaluated from a magnetic field dependence of the transistors resistance. High-mobility GaAs/GaAlAs Using the value of the mobility and the threshold transistors with a quality factor approaching 10 were voltage determined for different FETs we can estimate fabricated. These devices are most promising (among those their parameters for possible applications in the resonant investigated) devices for application as resonant detectors.

detectors of the terahertz radiation. In Fig. 10, we show We thank M. Dyakonov and S. Rumyantsev for helpful the frequency of the resonant detection and the quality discussions.

factor as a function of the swing voltage. The maximum frequency for a detector is determined by the maximum gate voltage swing and the gate length. As discussed before, the maximum gate voltage swing is determined by the References carrier density threshold voltage. It is usually slightly more negative than the transistor threshold voltage. The maximum [1] A.C. Samuels, D.L. Woolard, T. Globus, B. Gelmont, gate voltage swing is about 0.5 V for the group A and B E.R. Brown, J.O. Jensen, R. Suenram, W.R. Loerop. Environtransistors and 1.5 V for the group C. We took gate length mental Sensing of Chemical and Biological Warfare Agents in the THz Region. WOFE-02 Proceedings. Yoon Soo Park / L = 0.15 m for the group A and L = 0.8 m (shortest Ed. by Michael S. Shur, William Tang. (2002).

gates on a dice) for the group B and C. The mobility was [2] B. Ferguson, X.-C. Zhang. Nature Materials 1, 26 (2002).

assumed to be 6, 14 and 1 m2/Vs for the group A, B and [3] M. Kroug, S. Cherednichenko, H. Merkel, E. Kollberg, C, respectively.

B. Voronov, G. Goltsman, H.W. Huebers, H. Richter. IEEE As can be seen from the figure, the maximum frequency Transactions on Applied Superconductivity 11, 962 (2001).

of the group A devices is approximately 1.5 THz. The [4] P.J. Burke, R.J. Schoelkopf, D.E. Prober, A. Skalare, points shown in Fig. 10 represent the results of recent B.S. Karasik, M.C. Gaidis, W.R. McGrath, B. Bumble, experiments [14,15]. The plasma resonance observed in H.G. LeDuc. J. Appl. Phys. 85, 1644 (1999).

the experiments were relatively weak (Fig. 1). This can be [5] B.S. Karasik, W.R. McGrath, M.E. Gershenson, A.V. Sergeev.

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Compound Semiconductor Electronics / Ed. by M. Shur.

can be obtained for these devices is around 1.5. The World Scientific Publishing (1996). P. 209.

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about 2. It means that these devices can not be used for [8] E.E. Haller, J.W. Beeman. In: Proceedings of Far-IR, Subresonant tuneable detection. The best quality factors were mm & mm Detector Technology Workshop, April 2002, obtained for group B transistors. At the maximum operation Monterey, CA, in press.

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, 2004, 46, . Magnetotransport characterization of THz detectors based on plasma oscillations in submicron field... [12] For review see M. Dyakonov, M.S. Shur. In: Terahertz Sources and Systems / Ed. by R.E. Miles. Kluwer Academic Publ., Netherlands (2001). P. 187.

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10 , 2004, 46, .

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