الخلاصة

In this work gas sensor based on a TiO2 nanostructure has been investigated to employ it to detect and measurement percentage of presence of nitrogen dioxide in the air specimen. TiO2 was fabricated using dc magnetron sputtering method, pure Ti (99.99%) used as sputtering target, the oxygen/argon rate flow rate was settled at (50:50 sccm), the chamber presser was controlled to remain it at (0.2 Pa) during the deposition process and direct voltage for the sputtering operation was 1000 V with 100W power. Xray diffraction pattern show that the structure of all TiO2 films is polycrystalline with three phases Anatase, Brookite and Rutile with preferential orientation in the (112) direction. For TiO2 metal oxides, the annealed sensor exhibit variation of the conductance upon exposure to NO2 gas and showing excellent sensitivity. The high sensitivity for NO2 gas can be achieved with annealing the film and the sensitivity of the TiO2 thin films changes linearly with the increase of the gas concentration. The response – recovery time of TiO2 materials to NO2 gas is characterized to be relatively exceedingly short. TiO2 thin films have the highest sensitivity of 95% and exceedingly short response time of 2 s.