Stable and highly sensitive gas sensors based on semiconducting oxide nanobelts

Gas sensors have been fabricated using the single-crystalline $SnO2$ nanobelts. Electrical characterization showed that the contacts were ohmic and the nanobelts were sensitive to environmental polluting species like CO and $NO2,$ as well as to ethanol for breath analyzers and food control applications. The sensor response, defined as the relative variation in conductance due to the introduction of the gas, is 4160% for 250 ppm of ethanol and $−1550%$ for 0.5 ppm $NO2$ at $400 °C.$ The results demonstrate the potential of fabricating nanosized sensors using the integrity of a single nanobelt with a sensitivity at the level of a few ppb.