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

Sensors

Elizabeth C. Dickey¹  Oomman K. Varghese¹  Keat G. Ong²  Dawei Gong²  Maggie Paulose² 

[1] Department of Materials Science & Engineering, The Pennsylvania State University, University Park, PA 16802;Department of Electrical Engineering & Materials Research Institute, The Pennsylvania State University, University Park, PA 16802

关键词: Ammonia;    Nanoporous;    Impedance spectroscopy;    Alumina;    Humidity;    Mesoporous;   

DOI  :  10.3390/s20300091

来源: mdpi

【 摘 要 】

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.

【 授权许可】

Unknown   
© 2002 by MDPI (http://www.mdpi.net).