Lieberzeit, P., Afzal, A., Rehman, A., & Dickert, F. (2007). Nanoparticles for detecting pollutants and degradation processes with mass-sensitive sensors. Sensors and Actuators B: Chemical, 127(1), 132–136.
Abstract: Compared with thin films, nanoparticle layers as coatings for QCM offer substantially increased interaction areas and sensitivities with favourable response times. Molybdenum disulphide (MoS2), e.g. has turned out to be a highly suitable material for interacting with thiols. The resulting materials are sufficiently soft according to Pearson to bind sulphur containing compounds reversibly. Depositing MoS2 nanoparticle submonolayers (particle size 200–300 nm) leads to an increase in sensor response by a factor of ten compared to a pure gold layer. Additionally, the nanoparticle layers show fully reversible sensor signals. Particle synthesis can also be combined with the molecular imprinting approach: by a precipitation technique, it is possible to generate molecularly imprinted TiO2 particles for engine oil degradation measurements. Compared with deposited thin layers, particles incorporate oxidised compounds from lubricants by a factor of two better.
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Marsili, F., Bitauld, D., Fiore, A., Gaggero, A., Leoni, R., Mattioli, F., et al. (2009). Superconducting parallel nanowire detector with photon number resolving functionality. J. Modern Opt., 56(2-3), 334–344.
Abstract: We present a new photon number resolving detector (PNR), the Parallel Nanowire Detector (PND), which uses spatial multiplexing on a subwavelength scale to provide a single electrical output proportional to the photon number. The basic structure of the PND is the parallel connection of several NbN superconducting nanowires (100 nm-wide, few nm-thick), folded in a meander pattern. Electrical and optical equivalents of the device were developed in order to gain insight on its working principle. PNDs were fabricated on 3-4 nm thick NbN films grown on sapphire (substrate temperature TS=900C) or MgO (TS=400C) substrates by reactive magnetron sputtering in an Ar/N2 gas mixture. The device performance was characterized in terms of speed and sensitivity. The photoresponse shows a full width at half maximum (FWHM) as low as 660ps. PNDs showed counting performance at 80 MHz repetition rate. Building the histograms of the photoresponse peak, no multiplication noise buildup is observable and a one photon quantum efficiency can be estimated to be QE=3% (at 700 nm wavelength and 4.2 K temperature). The PND significantly outperforms existing PNR detectors in terms of simplicity, sensitivity, speed, and multiplication noise.
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Gol'tsman, G. N., Semenov, A. D., Gousev, Y. P., Zorin, M. A., Gogidze, I. G., Gershenzon, E. M., et al. (1991). Sensitive picosecond NbN detector for radiation from millimetre wavelengths to visible light. Supercond. Sci. Technol., 4(9), 453–456.
Abstract: The authors report on the application of a broad-band NbN film detector which has high sensitivity and picosecond response time for detection of radiation from millimetre wavelengths to visible light. From a study of amplitude modulated radiation of backward-wave tubes and picosecond pulses from gas and solid state lasers at wavelengths between 2 mm and 0.53 mu m, they found a detectivity of 1010 W-1 cm Hz-1/2 and a response time of less than 50 ps at T=10 K. The characteristics were provided by using a 150 AA thick NbN film patterned into a structure of micron strips. According to the proposed detection mechanism, namely electron heating, they expect an intrinsic response time of approximately 20 ps at the same temperature.
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Danerud, M., Winkler, D., Lindgren, M., Zorin, M., Trifonov, V., Karasik, B., et al. (1994). A fast infrared detector based on patterned YBCO thin film. Supercond. Sci. Technol., 7(5), 321–323.
Abstract: Detectors for infrared radiation ( lambda =0.85 mu m) were made of 50 nm thick YBa2Cu3O7- delta films on LaAlO3 and MgO or 60 nm thick films on NdGaO3. Parallel strips (1 mu m wide by 20 mu m long) were patterned in the films and formed the active device. These devices were designed to detect short infrared laser pulses by electron heating. The detectors were current biased into the resistive and the normal states. The response was studied in direct pulse measurements as well as by amplitude modulation of a laser. The pulse measurements showed a fast picosecond response followed by a slower decay related to phonon escape through the film-substrate interface and heat diffusion in the substrate. The frequency spectra up to 10 GHz showed two slopes with a knee corresponding to the phonon escape time.
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Sclafani, M., Marksteiner, M., Keir, F. M. L., Divochiy, A., Korneev, A., Semenov, A., et al. (2012). Sensitivity of a superconducting nanowire detector for single ions at low energy. Nanotechnol., 23(6), 065501 (1 to 5).
Abstract: We report on the characterization of a superconducting nanowire detector for ions at low kinetic energies. We measure the absolute single-particle detection efficiency eta and trace its increase with energy up to eta = 100%. We discuss the influence of noble gas adsorbates on the cryogenic surface and analyze their relevance for the detection of slow massive particles. We apply a recent model for the hot-spot formation to the incidence of atomic ions at energies between 0.2 and 1 keV. We suggest how the differences observed for photons and atoms or molecules can be related to the surface condition of the detector and we propose that the restoration of proper surface conditions may open a new avenue for SSPD-based optical spectroscopy on molecules and nanoparticles.
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