Assessment of titanium - tungsten iron oxide and their gas sensor application

The titanium iron oxide (TixFe3-xO4) x Fe 3-x O 4 ) and the tungsten iron oxide (WxFe3-xO4) x Fe 3-x O 4 ) structures were grown by the RF-DC magnetron co-sputtering technique. When examining the atomic percentages of the films grown under the same conditions the EDX measurements, different ratios are observed in the W x Fe 3-x O 4 structure (O: 71.05 %, Fe: 4.22 %, W: 24.74 %). The RF power supply seems to be causing more tungsten metal to be sputtered. This is the opposite in the structure of TixFe3-xO4 x Fe 3-x O 4 (O; 58.16 %, Fe; 41.68 %, Ti; 0.17 %). It is possible to say that the power source has an effect here, but also plasma thermodynamics and activation energies of metals play a significant role. The difference in the amount of oxygen in the structures is quite evident. The band gap energy of the as grown and annealing TixFe3-xO4 x Fe 3-x O 4 structures were determined to be 2.19 eV and 2.14 eV respectevily from absorption datas. Same way, as grown and annealing W x Fe 3-x O 4 structures were determined to be 3.09 eV and 3.15 eV respectevily. When examining the XRD results of the W x Fe 3-x O 4 crystal monoclinic structure and TixFe3-xO4 x Fe 3-x O 4 polycrystal both orthorhombic and cubic structures are observed. The response of W x Fe 3-x O 4 structure to hydrogen gas was measured at flow values of 1000 ppm, at 300 degrees, under white light and dark for 300, 180, 120 seconds, and it has been seen that the examined thin films are suitable for gas sensor application under white light. The W x Fe 3-x O 4 structure exhibits light sensitivity, despite having a relatively wide band gap. However, there is no evidence to suggest that this sensitivity is caused by hydrogen gas; but, it can be sait it is sensitive to light. Also, the response of TixFe3-xO4 x Fe 3-x O 4 structure was measured for 600 seconds, and it has been seen that the examined thin films are not suitable for gas sensor application under white light.

Journal

PHYSICS AND CHEMISTRY OF SOLID STATE

Year

2024

Volume

25

Issue

3

Pages

498-505

ISSN

1729-4428

eISSN

2309-8589

DOI

10.15330/pcss.25.3.498-505

WoS UID

WOS:001339191500009