Vacuum Evaporated Tin Oxide Thin Film Gas Sensors with Some Dopants

In automation, to increase the efficiency and capability of the instruments in measurement and detection technology, to reduce the cost, shape, size, weight etc., it is necessary to introduce the sensor units at the input ports of domestic, industrial and scientific instruments. Gases having some odour can be perceived by smell, but odourless and hazardous gases can be hardly detected. Semiconductor gas sensors are the best choice on these backgrounds to detect odorless and hazardous gases. Semiconductors are used as gas sensors based on the principle of the variability of electrical conductivity of metal oxides when exposed to these gases. Since 1962, Tin oxide semiconductor gas sensors have undergone extensive research and development in this regard. It is the dominant choice for solid state gas detectors in domestic, commercial and industrial applications due to the low operating temperatures, high sensitivities, mechanical simplicity of sensor design and low manufacturing costs. Contamination free Thin Films samples can be prepared using Physical Vapour Deposition under high vacuum and at room temperature. Such Thin Film samples annealed suitably can be used as gas sensors.