Toward the nanoscopic electronic nose: Hydrogen vs carbon monoxide discrimination with an array of individual metal oxide nano- and mesowire sensors

The array of chemiresistors made of individual pristine SnO2, surface doped (Ni)-SnO2 nanowires, and TiO2 and In2O3 mesoscopic whiskers was fabricated on a Si/SiO2 wafer. Their conductance was measured under pulses of H-2 and CO reducing gases in oxygen as background gas. The nanostructures were shown to be n-type semiconductors possessing high sensitivity to the target gases. Following the electronic nose concept, correlation analysis of response of three-chemiresistor array is shown to be sufficient to discriminate between H-2 and CO signals.