Fabrication of tin dioxide nanowires with ultrahigh gas sensitivity by atomic layer deposition of platinum

Gas-sensing properties of SnO2 nanowires were investigated before and after their surface functionalization by the atomic layer deposition (ALD) of Pt nanoparticles. The morphology, size, and concentration of Pt particles on SnO2 nanowires can be controlled by varying the number of ALD reaction cycles, and therefore, the gas-sensing properties of the nanowires can be altered via the Pt catalyst effect and the modification of Schottky barrier junctions on the nanowire surface in the vicinity of Pt nanoparticles. The Pt-decorated SnO2 nanowires obtained after 200 ALD reaction cycles exhibited an ultrahigh gas sensitivity (S = I-g/I-a) of similar to 8400 to 500 ppm ethanol vapor at 200 degrees C. This provides an efficient route for strongly enhancing the gas sensitivity of semiconducting nanostructures and fabricating gas sensors that are highly sensitive and responsive.