PT-SNO2 THIN-FILMS FOR GAS SENSOR CHARACTERIZED BY ATOMIC-FORCE MICROSCOPY AND X-RAY PHOTOEMISSION SPECTROMICROSCOPY

SnO2 thin films have been grown by radio frequency reactive sputtering method in order to be used as a gas sensor. Subsequently Pt has been added to the SnO2 films to increase the sensitivity to carbon monoxide gas. Two different substrates have been used: rough and mechanically polished alumina. The morphology of the film has been characterized by atomic force microscopy, whereas the chemical composition was analyze d by x-ray photoemission spectromicroscopy. Pt:SnO2 clusters with widt hs of 500-600 nm were observed on the rough alumina, whereas on the me chanically polished alumina, the Pt:SnO2 film was smoother. X-ray phot oemission spectromicroscopy measurements show for Pt:SnO2 films on rou gh alumina substrates different charging in different areas of the sam ple. The response curve to carbon monoxide is 30% higher for rough alu mina. (C) 1996 American Vacuum Society.