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 H2 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 H2 and CO signals.