Journal of Materials Science: Materials in Electronics

, Volume 22, Issue 9, pp 1420–1425 | Cite as

Effect of formaldehyde gas adsorption on the electrical conductivity of Pd-doped TiO2 thin films

  • A. YildizEmail author
  • D. Crisan
  • N. Dragan
  • N. Iftimie
  • D. Florea
  • D. Mardare


0.5 wt% Pd-doped titanium oxide thin films were obtained by dip-coating on silicon substrates. The films were compacted by annealing in air at 300 and 500 °C. Temperature dependent electrical conductivity measurements were performed in the temperature range 373–623 K, in different environments (air, methane, acetone, ethanol, formaldehyde and liquefied petroleum gas), to test the films sensing gas properties. Formaldehyde was found to be the test gas that produces the most significant changes in the electrical conductivity of the studied films. This was the reason why it was chosen to investigate its effect on their electrical conductivity. A model was proposed, the model of the potential fluctuations at grain boundaries. A comparison between some parameters obtained in the proposed model was performed as a function of annealing temperature, and as a function of gas atmosphere. The values of the mean barrier height and the standard deviation were estimated to range between 0.336–0.588 eV and 0.175–0.199 eV, respectively. It was found that formaldehyde leads to a rather sharp decrease in the values of the barrier height and the standard deviation, and to an increase in the conductivity. We have observed the best sensing gas performance for the films annealed at 300 °C, comparing to their counterparts annealed at 500 °C, explained by the lowest values of the barrier energy height and the standard deviation.


TiO2 SnO2 Barrier Height TiO2 Film HCHO 
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D. Mardare acknowledges the financial support from the grants PCCE-ID_76 and 12-128/2008.


  1. 1.
    Formaldehyde Epidemiology, Toxicology and Environmental Group, Formaldehyde and Facts About Health Effects (2002).
  2. 2.
    L. Feng, Y.J. Liu, X.D. Zhou, J.M. Hu, J. Colloid Interface Sci. 284, 378 (2005)CrossRefGoogle Scholar
  3. 3.
    O. Hernandez, L. Rhomberg, K. Hogan, C. Siegel-Scott, D. Lai, G. Grindstaff, M. Henry, J.A. Cotruvo, J. Hazard. Mater. 39(2), 161 (1994)CrossRefGoogle Scholar
  4. 4.
    J. Flueckiger, F.K. Ko, K.C. Cheung, Sensors 9, 9196 (2009)CrossRefGoogle Scholar
  5. 5.
    N. Iftimie, M. Crisan, A. Braileanu, D. Crisan, A. Nastuta, G.B. Rusu, P.D. Popa, D. Mardare, J. Optoelectron. Adv. M. 10, 9–2363 (2008)Google Scholar
  6. 6.
    H. Tang, K. Prasad, R. Sanjinès, F. Lévy, Sensor Actuat. B 26–27, 71 (1995)CrossRefGoogle Scholar
  7. 7.
    F. Cosandey, G. Skandan, A. Singhal, JOM-e, 52(10) (2000),
  8. 8.
    W.K. Choi, S.K. Song, J.S. Cho, Y.S. Yoon, D. Choi, H.-J. Jung, S.K. Koh, Sensor Actuat. B 40, 21 (1997)CrossRefGoogle Scholar
  9. 9.
    N. Yamazoe, Sensor Actuat. B 5, 7 (1991)CrossRefGoogle Scholar
  10. 10.
    A. Yildiz, S.B. Lisesivdin, M. Kasap, D. Mardare, J. Non-Cryst. Solids 354, 4944 (2008)CrossRefGoogle Scholar
  11. 11.
    A. Yildiz, S.B. Lisesivdin, M. Kasap, D. Mardare, Physica B 404, 1423 (2009)CrossRefGoogle Scholar
  12. 12.
    A. Yildiz, S.B. Lisesivdin, M. Kasap, D. Mardare, J. Mater, Sci. Mater. Electron. 21, 692 (2010)CrossRefGoogle Scholar
  13. 13.
    A. Yildiz, N. Serin, M. Kasap, T. Serin, D. Mardare, J. Alloys Compd. 493, 227 (2010)CrossRefGoogle Scholar
  14. 14.
    T. Serin, A. Yildiz, N. Serin, N. Yıldırım, F. Özyurt, M. Kasap, J. Electron. Mater. 39, 1152 (2010)CrossRefGoogle Scholar
  15. 15.
    A. Yildiz, A.A. Alsaç, T. Serin, N. Serin, J. Electron. Mater (2011). doi: 10.1007/s10854-010-0228-2 Google Scholar
  16. 16.
    A. Yildiz, F. Iacomi, D. Mardare, J. Appl. Phys 108, 083701 (2010)CrossRefGoogle Scholar
  17. 17.
    H.J. Höfler, H. Hahn, R.S. Averback, Defect Diffus. Forum 75, 195 (1991)CrossRefGoogle Scholar
  18. 18.
    J.Y.W. Seto, J. Appl. Phys 46, 5247 (1975)CrossRefGoogle Scholar
  19. 19.
    J.H. Werner, Solid State Phenom. 37, 213 (1994)CrossRefGoogle Scholar
  20. 20.
    D. Crisan, N. Dragan, M. Crisan, M. Raileanu, A. Braileanu, M. Anastasescu, A. Ianculescu, D. Mardare, D. Luca, V. Marinescu, A. Moldovan, J. Phys. Chem. Solids 69, 2548 (2008)CrossRefGoogle Scholar
  21. 21.
    D. Mardare, G.I. Rusu, J. Non-Cryst. Solids 28–30, 1395 (2010)CrossRefGoogle Scholar
  22. 22.
    T. Wolkenstein, Electronic Process on Semiconductor Surfaces During Chemisorption (Consultats Bureau, New York, 1991)CrossRefGoogle Scholar
  23. 23.
    S. Seeger, R. Mientus, J. Röhrich, E. Strub, W. Bohne, K. Ellmer, Surf. Coat. Technol. 200, 218 (2005)CrossRefGoogle Scholar
  24. 24.
    F. Kopnov, A. Yoffe, G. Leitus, R. Tenne, Phys. Stat. Sol. (b) 243, 1229 (2006)CrossRefGoogle Scholar
  25. 25.
    J.R. Ares, A. Pascual, I.J. Ferrer, C.R. Sanchez, Thin Solid Films 451, 233 (2004)CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  • A. Yildiz
    • 1
    Email author
  • D. Crisan
    • 2
  • N. Dragan
    • 2
  • N. Iftimie
    • 3
  • D. Florea
    • 4
  • D. Mardare
    • 4
  1. 1.Department of Physics, Faculty of Science and ArtsAhi Evran UniversityKirsehirTurkey
  2. 2.Institute of Physical Chemistry “Ilie Murgulescu”BucharestRomania
  3. 3.National Institute of Research and Development for Technical PhysicsIasiRomania
  4. 4.Faculty of PhysicsAlexandru Ioan Cuza UniversityIasiRomania

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