Gas sensing properties of W6 +–TiO2 thin film prepared by R.F. magnetron sputtering based on PN junction substrate

The techniques outlined here offer new means for preparing novel metal-oxide gas sensor with structural substrate which is compatible with IC technology. N-type W6 +–TiO2 gas-sensing layers have been deposited on PN junction substrate by R.F. magnetron sputtering. Structural characterization of TiO2 thin films has been analyzed by XRD and AFM in order to correlate physical properties with gas sensing performance. XRD and AFM indicate that the TiO2 keeps its anatase phase and its crystal lattice becomes larger with annealing temperature. The particle size at 400, 500 and 600 °C is 40, 60, and 100 nm, respectively. The sensors using W-doped TiO2 films showed promising gas sensing characteristics, such as low operation temperature (200 °C) and sufficient gas response, the sensitivity is 524%, respond and recover times are 11.2 s and 11.7 s, respectively.

► Novel metal-oxide gas sensor which is compatible with IC technology is fabricated.
► A linear relationship of sensitivity was obtained.
► In order to achieve sensing performance, the film is analyzed by XRD and AFM.
► The highest sensitivity is observed at 500 °C.
► The response and recovery times are 11.2 s and 11.7 s, respectively.