Author Affiliations
1S. N. Arts, D. J. M. Commerce and B. N. S. Science College Sangamner, District Ahmednagar 422 605 MS, India2Thin and Thick film Laboratory, Department of Electronics, M. S. G. College, Malegaon Camp (Pin 423105), District Nashik, Maharashtra, Indiashow less
Fig. 1. XRD patterns for pristine and Fe-doped TiO2 thin films annealed at 500 °C (# rutile).
Fig. 2. SEM image for (a) pristine TiO2, (b) 1 vol% Fe:TiO2, (c) 2 vol% Fe:TiO2 and (d) 4 vol% Fe:TiO2 samples.
Fig. 3. EDX spectrum of (a) pristine TiO2, (b) 1 vol% Fe:TiO2, (c) 2 vol% Fe:TiO2 and (d) 4 vol% Fe:TiO2 samples.
Fig. 4. (Color online) Variation of resistance with temperature for (a) pristine TiO2, (b) 1 vol% Fe:TiO2, (c) 2 vol% Fe:TiO2 and (d) 4 vol% Fe:TiO2 samples.
Fig. 5. (Color online) Variation of log(Ra) with temperature to calculated TCR for (a) pristine TiO2, (b) 1 vol% Fe:TiO2, (c) 2 vol% Fe:TiO2 and (d) 4 vol% Fe:TiO2 samples.
Fig. 6. (Color online) Variation of log(Ra) with 1000/T to calculate activation energy for (a) pristine TiO2, (b) 1 vol% Fe:TiO2, (c) 2 vol% Fe:TiO2 and (d) 4 vol% Fe:TiO2 samples.
Fig. 7. (Color online) Variation of resistance with percentage of relative humidity for (a) pristine TiO2, (b) 1 vol% Fe:TiO2, (c) 2 vol% Fe:TiO2 and (d) 4 vol% Fe:TiO2 samples.
Fig. 8. (Color online) Variation of sensitivity with percentage of relative humidity for (a) pristine TiO2, (b) 1 vol% Fe:TiO2, (c) 2 vol% Fe:TiO2 and (d) 4 vol% Fe:TiO2 samples.
Fig. 9. (Color online) Variation of sensitivity with percentage of relative humidity for different time interval for 2 vol% Fe :TiO2 sample.
Fig. 10. (Color online) Hysteresis loops for for (a) pristine TiO2, (b) 1 vol% Fe:TiO2, (c) 2 vol% Fe:TiO2 and (d) 4 vol% Fe:TiO2 samples.
Fig. 11. (Color online) Variation of resistance with time to calculate response and recovery time for pristine TiO2, 1 vol% Fe:TiO2, 2 vol% Fe:TiO2 and 4 vol% Fe:TiO2 samples.
Fig. 12. (Color online) Variation sensitivity and response time with different Fe vol% for Fe doped TiO2 thin films.
Sample | Fe
(vol%)
| Crystallite
size (nm)
| Interplaner
distance (Å)
| Crystal
phase
| Texture
coefficient
| Microstain (10–3)
| Dislocation
(1014 cm–2)
| Specific surface
area (m2/g)
|
---|
Pristine | – | 31.21260 | 3.513233 | A | 1.5622 | 1.764 | 10.2646 | 49.416 | 1 vol% Fe:TiO2 | 1 | 28.25648 | 3.514076 | A | 1.4996 | 1.87 | 12.5246 | 54.586 | 2 vol% Fe:TiO2 | 2 | 25.07873 | 3.511046 | A | 1.0788 | 1.90 | 15.8997 | 61.502 | 4 vol% Fe:TiO2 | 4 | 24.69604 | 3.510535 | A - 90.77 %
R - 9.23 %
| 0.4755 | 2.48 | 16.3963 | 62.456 |
|
Table 1. Structural properties of pristine and Fe-doped TiO2 thin films.
Sample | Fe (vol%) | Oxygen (at%) | Titanium (at%) | Fe (at%) |
---|
Pristine | – | 81.08 | 18.92 | – | 1 vol% Fe:TiO2 | 1 | 84.61 | 14.23 | 1.16 | 2 vol% Fe:TiO2 | 2 | 86.14 | 12.29 | 1.57 | 4 vol% Fe:TiO2 | 4 | 87.28 | 11.12 | 1.80 |
|
Table 2. EDX spectrum for pristine and Fe-doped TiO2 thin films.
Sample | Fe (vol%) | Room temp. resistance (MΩ) | TCR (°C–1)
| | Activation energy(eV)
|
---|
Heating | Cooling | | Heating | Cooling |
---|
Pristine | – | 382.4800 | –0.00140 | –0.007393 | | 0.3395 | 0.3537 | 1 vol% Fe:TiO2 | 1 | 384.7108 | –0.00124 | –0.005736 | | 0.4499 | 0.4673 | 2 vol% Fe:TiO2 | 2 | 258.5140 | –0.00081 | –0.001172 | | 0.4947 | 0.5137 | 4 vol% Fe:TiO2 | 4 | 212.2913 | –0.00034 | –0.000738 | | 0.5201 | 0.5348 |
|
Table 3. Electrical resistance, TCR and activation energy for pristine and Fe-doped TiO2 thin films.
Sample | Fe (vol%) | Sensitivity | Response time (s) | Recovery time (s) | % of hysteresis loss |
---|
Pristine | – | 83.72 | 77.5 | 3 | 1.19 | 1 vol% Fe:TiO2 | 1 | 86.71 | 62.5 | 3 | 3.11 | 2 vol% Fe:TiO2 | 2 | 88.68 | 52 | 3 | 3.66 | 4 vol% Fe:TiO2 | 4 | 80.47 | 82.5 | 4 | 5.34 |
|
Table 4. Sensitivity, response, recovery time and % of hysteresis loss for pristine and Fe-doped TiO2 thin films.