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 degreesC. 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. (C) 2002 American Institute of Physics.