SnO2 microwires, nanowires and rice-shaped nanoparticles were synthesized by a thermal evaporation
method. The diameters of microwire and nanowire were 2mand 50–100 nm, respectively, with approximately
the same length (∼20m). The size of nanoparticles was about 100 nm. It was confirmed that
the as-synthesized products have SnO2 crystalline rutile structure. The sensing ability of SnO2 particle
and wire-like structure configured as gas sensors was measured. A comparison between the particle and
wire-like structure sensors revealed that the latter have numerous advantages in terms of reliability and
high sensitivity. Although its high surface-to-volume ratio, the nanoparticle sensor exhibited the lowest
sensitivity. The high surface-to-volume ratio and low density of grain boundaries is the best way to
improve the sensitivity of SnO2 gas sensors, as in case of nanowire sensor which exhibited a dramatic
improvement in sensitivity to NO2 gas.