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Sensors 2002, 2(3), 91-110; doi:10.3390/s20300091
Article

Room Temperature Ammonia and Humidity Sensing Using Highly Ordered Nanoporous Alumina Films

1,* , 1, 2, 2, 2 and 2
Received: 9 February 2002; Accepted: 1 March 2002 / Published: 18 March 2002
(This article belongs to the Special Issue Nano-Porous Sensor Material)
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Abstract: The effect of pore size and uniformity on the response of nanoporous alumina, formed on aluminum thick films through an anodization process, to ammonia and humidity at room temperature is reported. Pore sizes examined range from 13 nm to 48 nm, with pore size standard deviations ranging from 2.6 nm to 7.8 nm. The response of the material to ammonia and humidity is a strong function of pore size and operating frequency. At 5 kHz an alumina sensor with an average pore size of 13.6 nm, standard deviation 2.6 nm, exhibits a factor of two change in impedance magnitude as it is cycled between an ammonia and argon environment. At 5 kHz the same sensor exhibits a well-behaved change in impedance magnitude of 103 over 20% to 90% relative humidity. Cole-Cole plots of the 5 Hz to 13 MHz measured impedance spectra, modeled using equivalent circuits, are used to resolve the effects of adsorption and ion migration.
Keywords: Ammonia; Nanoporous; Impedance spectroscopy; Alumina; Humidity; Mesoporous Ammonia; Nanoporous; Impedance spectroscopy; Alumina; Humidity; Mesoporous
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Dickey, E.C.; Varghese, O.K.; Ong, K.G.; Gong, D.; Paulose, M.; Grimes, C.A. Room Temperature Ammonia and Humidity Sensing Using Highly Ordered Nanoporous Alumina Films. Sensors 2002, 2, 91-110.

AMA Style

Dickey EC, Varghese OK, Ong KG, Gong D, Paulose M, Grimes CA. Room Temperature Ammonia and Humidity Sensing Using Highly Ordered Nanoporous Alumina Films. Sensors. 2002; 2(3):91-110.

Chicago/Turabian Style

Dickey, Elizabeth C.; Varghese, Oomman K.; Ong, Keat G.; Gong, Dawei; Paulose, Maggie; Grimes, Craig A. 2002. "Room Temperature Ammonia and Humidity Sensing Using Highly Ordered Nanoporous Alumina Films." Sensors 2, no. 3: 91-110.



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