The characterization of nanostructured copper-doped tin oxide films for gas sensor microarrays

In this paper, we describe thin nanostructured SnO/sub 2/:Cu films fabricated by RF magnetron sputtering and characterized with a variety of surface analytical techniques. The average grain size of the 200-1000 nm thick films with columnar structure was determined to be 20-100 nm. A slight oxygen deficiency was observed at the film surface by XPS with [O]/[Sn] ratio equal to about 1.6. Based on these films, gas sensor microarrays of the KAMINA (Karlsruhe Micronose) type were built up. The gas sensitivity of the film sensor segments operated at 350/spl deg/C was found suitable to respond to tested reducing gases (ammonia, acetone, alcohols) with response times of less than 10 sec.