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IF impedance and mixer gain of NbN hot electron bolometers

Kooi, J. W. and Baselmans, J. J. A. and Hajenius, M. and Gao, J. R. and Klapwijk, T. M. and Dieleman, P. and Baryshev, A. and de Lange, G. (2007) IF impedance and mixer gain of NbN hot electron bolometers. Journal of Applied Physics, 101 (4). Art. No. 044511. ISSN 0021-8979. doi:10.1063/1.2400086.

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The intermediate frequency (IF) characteristics, the frequency dependent IF impedance, and the mixer conversion gain of a small area hot electron bolometer (HEB) have been measured and modeled. The device used is a twin slot antenna coupled NbN HEB mixer with a bridge area of 1×0.15 µm^2, and a critical temperature of 8.3 K. In the experiment the local oscillator frequency was 1.300 THz, and the (IF) 0.05–10 GHz. We find that the measured data can be described in a self-consistent manner with a thin film model presented by Nebosis et al. [Proceedings of the Seventh International Symposium on Space Terahertz Technology, Charlottesville, VA, 1996 (unpublished), pp. 601–613], that is based on the two temperature electron-phonon heat balance equations of Perrin-Vanneste [J. Phys. (Paris) 48, 1311 (1987)]. From these results the thermal time constant, governing the gain bandwidth of HEB mixers, is observed to be a function of the electron-phonon scattering time, phonon escape time, and the electron temperature. From the developed theory the maximum predicted gain bandwidth for a NbN HEB is found to be 5.5–6 GHz. In contrast, the gain bandwidth of the device under discussion was measured to be ~2.3 GHz which, consistent with the outlined theory, is attributed to a somewhat low critical temperature and nonoptimal film thickness (6 nm).

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Kooi, J. W.0000-0002-6610-0384
Additional Information:©2007 American Institute of Physics. (Received 4 August 2006; accepted 19 September 2006; published online 27 February 2007) The authors thank Willem Jellema, Ronald Hesper, Wolfgang Wild, Thijs de Graauw, and Tom Phillips for their support. They would also like to thank Youjin Deng at Theoretical Physics Group at Delft for checking the mathematical solutions of the time dependent heat balance equations. This work was supported in part by NSF Grant No. AST-0229008 and Radionet.
Subject Keywords:niobium compounds; superconducting thin films; bolometers; superconducting mixers; electron-phonon interactions; superconducting infrared, submillimeter and millimeter wave detectors
Issue or Number:4
Record Number:CaltechAUTHORS:KOOjap07
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7538
Deposited By: Archive Administrator
Deposited On:02 Mar 2007
Last Modified:08 Nov 2021 20:43

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