Fabrication And Characterization Of Gas Sensor Based On SnO₂ One-dimensional Nanostructures

With developing of industry, more and more exhaust gases produced as well as wealth, which are not only non-friendly to the environment but also dangerous. Therefore, high sensitive gas sensors are very essential for detecting the contaminative and poisonous gases. Gas sensors based on metal oxide semiconductors have the advantages of high-sensitivity, nice-selectivity as well as easy miniaturization and automation. They can be applied to a wide range of application, such as industry control and environment monitor. Nano-structures of metal oxide semiconductors, exhibiting a large specific volume, might be favorable for improving the sensitivity of gas-sensors. Therefore, fabrication of gas sensors based on nanostructures has been currently research focus. On the other hand, surface modification of nanostructures by additives or dopants is often used to improve the response time and selectivity of gas sensor.Two types of tin oxide self-assembly nanostructures have been successfully synthesized by chemical vapor deposition method. By charactering with scanning electron microscopy and X-ray diffraction, possible growth mechanism for these two types of self-assembly tin oxide nano-structrues has been proposed.Gas sensors based on the film of SnO₂ nanoparticles and the films of SnO₂ nanowires have been fabricated and characterized under different atmosphere, different temperature and even different illumination. The experimental results show that the resistance of the nanowire films is more sensitive to gas or light exposition than that of the nanoparticle film, which indicates that SnO₂ nanowires is much more suitable for gas sensing.