Preparation of Nanostructured SnO2 Thick Films Onto Patterned Pt Electrodes by Ink Dropping and Plasma Surface Treatment for CO Gas Sensor

Abstract

Nanostructured SnO2 thick films with pure tetragonal phases onto patterned Pt electrodes have been prepared by ink dropping and plasma surface treatment for CO gas sensors. Fine SnO2 powder with a diameter of 30 nm was synthesized by modified hydrazine method and the ink solution was fabricated by mixing water, glycerol, bicine, and the SnO2 powder. Crack-free films without agglomeration could be obtained by controlling the SnO2 powder content in the ink and heating rate during final sintering. The region of formed SnO2 thick films by the ink dropping was able to successfully fill the 10-mu m gap of patterned Pt electrodes. Additionally, plasma surface treatment was introduced prior to ink dropping in order to improve the adhesion strength and electrical connectivity between the SnO2 thick films and patterned Pt electrodes. The prepared nanostructured SnO2 thick films exhibited a gas sensitivity of 43%, a response time of 8.5 sec, and a recovery time of 34.2 sec at a CO gas concentration of 500 ppm and a temperature of 300 degrees C without any addition of catalyst.