Original title: IMPEDANCE MEASUREMENT OF GAS SENSORS WITH NICKEL(II)-AND COPPER(II)-OXIDE ACTIVE LAYERS
Authors: Horák, Pavel ; Khun, J. ; Vrňata, M. ; Bejšovec, Václav ; Lavrentev, Vasyl ; Vacík, Jiří
Document type: Papers
Conference/Event: NANOCON 2014. International Conference /6./, Brno (CZ), 2014-11-05 / 2014-11-07
Year: 2015
Language: eng
Abstract: Thin layers (90 nm) of nickel(II)- and copper(II)- oxide were deposited onto ceramic sensor substrates equipped with interdigital electrodes for signal reading. The deposition was carried out in two or three steps: (i) sputtering by means of Ar ion beam from pure (99.99%) metal targets, (ii) following thermal oxidation (400 degrees C for 5 h) in air, (iii) in some cases - sputtering of Pd catalyst to the surface. Then the impedance response of produced sensors (NiO, NiO+Pd, CuO, CuO+Pd) to 1000 ppm of hydrogen and 1000 ppm of methanol vapor was measured. Impedance measurements were performed in the frequency range from 40 Hz to 100 MHz. The obtained data were depicted in Nyquist representation (i.e. imaginary vs. real part of complex impedance). These diagrams have a character of one complete and one incomplete semicircle, each of them corresponding to a parallel RC-element. It was proved, that both NiO and CuO behave like p-type semiconductors; the sensor impedance increases on exposure to reducing gases. The best sensitivity was achieved on NiO+Pd sensor - during detection of hydrogen (1000 ppm) the real part of complex impedance measured at 40 Hz increased from 120 to 350 Omega.
Keywords: gas sensors; impedance measurement; nickel(II) oxide and copper(II) oxide
Project no.: LM2011019 (CEP)
Funding provider: GA MŠk
Host item entry: NANOCON 2014. 6th International conference proceedings, ISBN 978-80-87294-53-6

Institution: Nuclear Physics Institute AS ČR (web)
Document availability information: Fulltext is available at the institute of the Academy of Sciences.
Original record: http://hdl.handle.net/11104/0245953

Permalink: http://www.nusl.cz/ntk/nusl-181145


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