Semiconductor gas sensors have serious application in gas detection due to their low cost, simple detection method and easy to carry. SnO2 and In2O3, as surface-control type material, draw lots of attentions because of their high and stable sensitivity. In this thesis, SnO2 and In2O3 nanofibers are synthesized by electrospinning. Metal and metallic oxides are used to decorate on SnO2 and In2O3 nanofibers. The gas sensing properties of pure and decorated materials were compared and the gas sensing mechanism ...