Capacitive Humidity Sensors With High Sensitivity and Subsecond Response Times

Author

Steele, John J. ; Fitzpatrick, Glen A. ; Brett, Michael J.

Author_Institution

Dept. Electr. & Comput. Eng., Alberta Univ., Edmonton, Alta.

Volume

7

Issue

6

fYear

2007

fDate

6/1/2007 12:00:00 AM

Firstpage

955

Lastpage

956

Abstract

Capacitive-based humidity sensors were fabricated using coplanar interdigitated electrodes coated with nanostructured TiO₂ thin films produced by glancing angle deposition. In this letter, we show that increased sensitivity (nF/%RH) is obtained by decreasing the electrode periodicity or by increasing the planar area of the electrodes, or both. The devices were sensitive over a wide range of relative humidity levels (<1% to >92%) and exhibited extremely fast, subsecond response times. Typical adsorption and desorption response times were measured to be <220 and >400 ms, respectively

Keywords

capacitive sensors; electrodes; humidity sensors; semiconductor thin films; thin film sensors; titanium compounds; TiO₂; capacitive humidity sensors; coplanar interdigitated electrodes; electrode periodicity; glancing angle deposition; high sensitivity; nanostructured thin films; response times; subsecond response times; Capacitive sensors; Delay; Electrodes; Humidity; Monitoring; Nanostructures; Optical sensors; Sputtering; Substrates; Thin film sensors; Glancing angle deposition (GLAD); humidity; nanostructured; porous; thin film;

fLanguage

English

Journal_Title

Sensors Journal, IEEE

Publisher

ieee

ISSN

1530-437X

Type

jour

DOI

10.1109/JSEN.2007.897363

Filename

4162474