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Gao, B. (author), Osorio, E.A. (author), Babaei Gaven, K. (author), Van der Zant, H.S.J. (author)We have fabricated nanometer-spaced electrodes on electron-transparent silicon nitride membranes. A thin Cr/Au layer is evaporated on the backside of the membrane which serves as a gate electrode. Using these devices, we have performed three-terminal electron transport measurements on gold nano-particles at liquid helium temperature. Coulomb...journal article 2009
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Khosropanah, P. (author), Baryshev, A. (author), Zhang, W. (author), Jellema, W. (author), Hovenier, J.N. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Paveliev, D.G. (author), Williams, B.S. (author), Kumar, S. (author), Hu, Q. (author), Reno, J.L. (author), Klein, B. (author), Hesler, J.L. (author)We demonstrate the phase locking of a 2.7 THz metal–metal waveguide quantum cascade laser (QCL) to an external microwave signal. The reference is the 15th harmonic, generated by a semiconductor superlattice nonlinear device, of a signal at 182 GHz, which itself is generated by a multiplier chain (x12) from a microwave synthesizer at ~15 GHz....journal article 2009
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Barends, R. (author), Hortensius, H.L. (author), Zijlstra, T. (author), Baselmans, J.J.A. (author), Yates, S.J.C. (author), Gao, J.R. (author), Klapwijk, T.M. (author)We present measurements of the frequency noise and resonance frequency temperature dependence in planar superconducting resonators on both silicon and sapphire substrates. We show, by covering the resonators with sputtered SiOx layers of different thicknesses, that the temperature dependence of the resonance frequency scales linearly with...journal article 2009
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Prins, F. (author), Hayashi, T. (author), De Vos van Steenwijk, B.J.A. (author), Gao, B. (author), Osorio, E.A. (author), Muraki, K. (author), Van der Zant, H.S.J. (author)We present a method to make Pt nanometer-spaced electrodes that are free of metallic particles and stable at ambient conditions. The nanogaps are fabricated using feedback-controlled electromigration to form few-atom contacts. When performing this procedure at elevated temperatures (>420?K), the Pt contacts undergo self-breaking so that...journal article 2009
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Barends, R. (author), Van Vliet, S. (author), Baselmans, J.J.A. (author), Yates, S.J.C. (author), Gao, J.R. (author), Klapwijk, T.M. (author)The quasiparticle recombination time in superconducting films, consisting of the standard electron-phonon interaction and a yet to be identified low-temperature process, is studied for different densities of magnetic and nonmagnetic atoms. For both Ta and Al, implanted with Mn, Ta, and Al, we observe an increase in the recombination rate. We...journal article 2009
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- Gao, Z. (author) journal article 2009
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Khosropanah, P. (author), Zhang, W. (author), Hovenier, J.N. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Amanti, M.I. (author), Scalari, G. (author), Faist, J. (author)We report a heterodyne receiver using a superconducting NbN hot electron bolometer (HEB) integrated with a tight winding spiral antenna as mixer and a distributed feedback (DFB) terahertz quantum cascade laser (QCL) operating at 3.42 THz as local oscillator. The aim is to demonstrate the readiness of both devices for the detection of OH lines at...journal article 2008
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Barends, R. (author), Baselmans, J.J.A. (author), Yates, S.J.C. (author), Gao, J.R. (author), Hovenier, J.N. (author), Klapwijk, T.M. (author)The quasiparticle relaxation time in superconducting films has been measured as a function of temperature using the response of the complex conductivity to photon flux. For tantalum and aluminum, chosen for their difference in electron-phonon coupling strength, we find that at high temperatures the relaxation time increases with decreasing...journal article 2008
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Barends, R. (author), Hortensius, H.L. (author), Zijlstra, T. (author), Baselmans, J.J.A. (author), Yates, S.J.C. (author), Gao, J.R. (author), Klapwijk, T.M. (author)We study NbTiN resonators by measurements of the temperature dependent resonance frequency and frequency noise. Additionally, resonators are studied covered with SiOx dielectric layers of various thicknesses. The resonance frequency develops a nonmonotonic temperature dependence with increasing SiOx layer thickness. The increase in the noise is...journal article 2008
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Hajenius, M. (author), Khosropanah, P. (author), Hovenier, J.N. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Barbieri, S. (author), Dhillon, S. (author), Filloux, P. (author), Sirtori, C. (author), Ritchie, D.A. (author), Beere, H.E. (author)We characterize a heterodyne receiver based on a surface-plasmon waveguide quantum cascade laser (QCL) emitting at 2.84 THz as a local oscillator, and an NbN hot electron bolometer as a mixer. We find that the envelope of the far-field pattern of the QCL is diffraction-limited and superimposed onto interference fringes, which are similar to...journal article 2008
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Khosropanah, P. (author), Gao, J.R. (author), Laauwen, W.M. (author), Hajenius, M. (author), Klapwijk, T.M. (author)We have studied the sensitivity of a superconducting NbN hot electron bolometer mixer integrated with a spiral antenna at 4.3?THz. Using hot/cold blackbody loads and a beam splitter all in vacuum, we measured a double sideband receiver noise temperature of 1300?K at the optimum local oscillator (LO) power of 330?nW, which is about 12 times the...journal article 2007
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Gao, J.R. (author), Hajenius, M. (author), Tichelaar, F.D. (author), Klapwijk, T.M. (author), Voronov, B. (author), Grishin, E. (author), Gol'tsman, G. (author), Zorman, C.A. (author), Mehregany, M. (author)The authors have realized NbN (100) nanofilms on a 3C-SiC (100)/Si(100) substrate by dc reactive magnetron sputtering at 800?°C. High-resolution transmission electron microscopy (HRTEM) is used to characterize the films, showing a monocrystalline structure and confirming epitaxial growth on the 3C-SiC layer. A film ranging in thickness from 3.4...journal article 2007
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Kooi, J.W. (author), Baselmans, J.J.A. (author), Hajenius, M. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Dieleman, P. (author), Baryshev, A. (author), De Lange, G. (author)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??m2, and a critical temperature of 8.3?K. In the experiment the...journal article 2007
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Baselmans, J.J.A. (author), Baryshev, A. (author), Reker, S.F. (author), Hajenius, M. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Voronov, B. (author), Gol'tsman, G. (author)We present a detailed experimental study of the direct detection effect in a small volume (0.15??m×1??m×3.5?nm) quasioptical NbN phonon cooled hot electron bolometer mixer at 673?GHz. We find that the small signal noise temperature, relevant for an astronomical observation, is 20% lower than the noise temperature obtained using 300 and 77?K...journal article 2006
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Hajenius, M. (author), Baselmans, J.J.A. (author), Baryshev, A. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Kooi, J.W. (author), Jellema, W. (author), Yang, Z.Q. (author)We present a complete experimental characterization of a quasioptical twin-slot antenna coupled small area (1.0×0.15??m2) NbN hot electron bolometer (HEB) mixer compatible with currently available solid state tunable local oscillator (LO) sources. The required LO power absorbed in the HEB is analyzed in detail and equals only 25?nW. Due to the...journal article 2006
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Kooi, J.W. (author), Baselmans, J.J.A. (author), Baryshev, A. (author), Schieder, R. (author), Hajenius, M. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Voronov, B. (author), Gol'tsman, G. (author)In this paper we discuss the stability of heterodyne terahertz receivers based on small volume NbN phonon cooled hot electron bolometers (HEBs). The stability of these receivers can be broken down in two parts: the intrinsic stability of the HEB mixer and the stability of the local oscillator (LO) signal injection scheme. Measurements show that...journal article 2006
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Baryshev, A. (author), Hovenier, J.N. (author), Adam, A.J.L. (author), Kaalynas, I. (author), Gao, J.R. (author), Klaassen, T.O. (author), Williams, B.S. (author), Kumar, S. (author), Hu, Q. (author), Reno, J.L. (author)We have studied the phase locking and spectral linewidth of an ? 2.7?THz quantum cascade laser by mixing its two lateral lasing modes. The beat signal at about 8?GHz is compared with a microwave reference by applying conventional phase lock loop circuitry with feedback to the laser bias current. Phase locking has been demonstrated, resulting in...journal article 2006
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Adam, A.J.L. (author), Kaalynas, I. (author), Hovenier, J.N. (author), Klaassen, T.O. (author), Gao, J.R. (author), Orlova, E.E. (author), Williams, B.S. (author), Kumar, S. (author), Hu, Q. (author), Reno, J.L. (author)The need to reach single-mode lasing and minimize at the same time the electrical dissipation of cryogenically operated terahertz quantum cascade lasers may result in small and subwavelength cavity dimensions. To assess the influence of such dimensions on the shape of the laser emission, we have measured the beam pattern of two metal-metal...journal article 2006
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- Yang, Z.Q. (author), Hajenius, M. (author), Baselmans, J.J.A. (author), Gao, J.R. (author), Voronov, B. (author), Gol'tsman, G.N. (author) journal article 2006
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- Orlova, E.E. (author), Hovenier, J.N. (author), Klaassen, T.O. (author), Kasalynas, I. (author), Adam, A.J.L. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Williams, B.S. (author), Kumar, S. (author), Hu, Q. (author), Reno, J.L. (author) journal article 2006