Chemiresistive Nanowire Gas Sensor

A metal-oxide nanowire suspended between two electrodes has an enormous surface-area-to-volume ratio: its entire cross-section is only a few atomic layers thick. This simulator drifts target gas molecules through the chamber, lets them adsorb onto the nanowire's surface, and tracks the resulting shift in electrical resistance in real time. A toggle swaps in a bulk sensor made of the same material exposed to the identical gas concentration, so the same fractional surface coverage produces a dramatic resistance swing on the nanowire but an almost imperceptible one on the bulk block — the mechanism behind parts-per-billion nanoscale gas detection.