| there are three crystalline phases for TiO2 , including rutile . anatase and brookite .Transformation of crystalline phase occurs at a certain temperature and pressure. TiO2 is a kind of multifunction material. TiO2 thin films is a kind of very important optical films which are high transmission rate and refractive rate in visible light area. TiO2 may serve to many kinds of sensors, which not only serve to humidity sensing sensors and pressure sensing sensors,but also serve to identify many kinds of gases,mostly to measuing oxygen. TiO2 is a good kind of optical catalyzer which can be used to get rid of contamination from air and purify air.This paper studys on TiO2 thin films which are deposited by DC magnetron sputtering.Annealing was carried out respectively from 300℃ to 1100℃. We found that TiO2 thin films are a amorphism when they are not annealed ;they are anatase when annealed at 300℃C; Rutile occured be anneled at 700℃; Ti02 thin films are transformed into rutile completely when be anneled at 1100℃. Oxygen-sensing properties of TiO2 thin films were analysised,and we found the variation law of sensitivity with the partial pressure of O2 and temperatures.Sensitivity increases with po2/(po2+pN2) at a constant temperature. Thehigher working temperature is ,the slower sensitivity increasing with Po2 /(Po2 + PN2 ) is . At 400℃, sensitivity increaing is fastest. Sensitivityis highest at 400℃. This working temperature is low compared to the other works. And activation energy was determined be equal to 0.4lev.
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