Applied Physics A

, 125:157 | Cite as

Effect of Al doping on the carrier transport characteristics of TiO2 thin films anchored on glass substrates

  • Shreesha Bhat
  • K. M. SandeepEmail author
  • Prasad Kumar
  • M. Parvathy Venu
  • S. M. Dharmaprakash
  • J. S. Bhat


Aluminium-doped TiO2 thin films are grown by sol–gel spin-coating method, and the impact of Al doping on structural, optical, and electrical properties is investigated. Morphology of the films exhibited decrease in the grain size with the increase in incorporation of Al dopants. EDS affirmed the presence of Al atoms in the doped films. A built-in tensile stress is observed with increasing dopant concentration in the films due to the deviation of the (101) plane from its ideal position. Raman spectra confirmed the anatase phase of TiO2 and effects of Al doping on it. A blue shift in the energy gap and an increase in the average transmittance of the Al doped samples are accounted. Ellipsometry revealed the decrease in refractive index and thickness of the film upon Al doping. The obtained non-linear refractive index values of the films showed a decreasing trend with increasing doping concentration due to the deteriorated polarizability in doped films. The predominance of grain-boundary scattering in the doped films is confirmed by the decreasing trend in the values of mobility and the mean-free path of the carriers. The mobility of the carriers is reduced by one order in doped films due to the dominant grain-boundary scattering mechanism.



The authors are very thankful to the Coordinator, DST PURSE, Microtron Centre of Mangalore University and UGC SAP, Department of Physics, Mangalore University, for providing facilities for the characterization of thin films and technical support to carry out the work. We are also thankful to DST PURSE, Karnatak University Dharwad, for providing characterization facility. SB acknowledges the UGC BSR for the financial support.


  1. 1.
    D. Sarkar, C.K. Ghosh, U.N. Maiti, K.K. Chattopadhyay, Effect of spin polarization on the optical properties of Co-doped TiO2 thin films. Phys. B-Condens. Matter. 406, 1429–1435 (2011). ADSCrossRefGoogle Scholar
  2. 2.
    A. Bouaine, G. Schmerber, D. Ihiawakrim, A. Derory, Structural, optical, and magnetic properties of polycrystalline Co-doped TiO2 synthesized by solid-state method. Mater. Sci. Eng. B. 177, 1618–1622 (2012). CrossRefGoogle Scholar
  3. 3.
    I.A. Al-Homoudi, J.S. Thakur, R. Naik, G.W. Auner, G. Newaz, Anatase TiO2 films based CO gas sensor: Film thickness, substrate and temperature effects. Appl. Surf. Sci. 253, 8607–8614 (2007). ADSCrossRefGoogle Scholar
  4. 4.
    F. Al-Juaid, A. Merazga, ZnO spin-coating of TiO2 photo-electrodes to enhance the efficiency of associated dye-sensitized solar cells, World J. Condens. Matter. Phys. 2012 (2012) 192–196.
  5. 5.
    V.C. Anitha, A.N. Banerjee, S.W. Joo, Recent developments in TiO2 as n- and p-type transparent semiconductors: synthesis, modification, properties, and energy-related applications. J. Mater. Sci. 50, 7495–7536 (2015). ADSCrossRefGoogle Scholar
  6. 6.
    V. Pore, M. Dimri, H. Khanduri, R. Stern, J. Lu, L. Hultman, K. Kukli, M. Ritala, M. Leskelä, Atomic layer deposition of ferromagnetic cobalt doped titanium oxide thin films. Thin Solid Films. 519, 3318–3324 (2011). ADSCrossRefGoogle Scholar
  7. 7.
    C. Garzella, E. Comini, E. Tempesti, C. Frigeri, G. Sberveglieri, TiO2 thin films by a novel sol–gel processing for gas sensor applications. Sens. Actuators B Chem. 68, 189–196 (2000). CrossRefGoogle Scholar
  8. 8.
    M.A.M. Al-Alwani, A.B. Mohamad, N.A. Ludin, A.A.H. Kadhum, K. Sopian, Dye-sensitised solar cells: Development, structure, operation principles, electron kinetics, characterisation, synthesis materials and natural photosensitisers. Renew. Sustain. Energy Rev. 65, 183–213 (2016). CrossRefGoogle Scholar
  9. 9.
    O. Engineering, titanium dioxide thin films in the 25.5-to 612-optical constants of e-beam evaporated titanium dioxide thin films in the 25.5- to 612-eV energy region Antonela Comisso, (2016).
  10. 10.
    C.W. Dunnill, A. Kafizas, I.P. Parkin, CVD production of doped titanium dioxide thin films. Chem. Vap. Depos. 18, 89–101 (2012). CrossRefGoogle Scholar
  11. 11.
    D.R. Acosta, A.I. Martínez, A.A. López, C.R. Magaña, Titanium dioxide thin films: The effect of the preparation method in their photocatalytic properties. J. Mol. Catal. A Chem. 228, 183–188 (2005). CrossRefGoogle Scholar
  12. 12.
    S. Sönmezoğlu, G. Çankaya, N. Serin, Phase transformation of nanostructured titanium dioxide thin films grown by sol–gel method. Appl. Phys. A. 107, 233–241 (2012). ADSCrossRefGoogle Scholar
  13. 13.
    F. Bensouici, M. Bououdina, A.A. Dakhel, T. Souier, R. Tala-ighil, M. Toubane, A. Iratni, S. Liu, W. Cai, Al doping effect on the morphological, structural and photocatalytic properties of TiO2 thin layers. Thin Solid Films. 616, 655–661 (2016). ADSCrossRefGoogle Scholar
  14. 14.
    S. Bhat, K.M. Sandeep, P. Kumar, S.M. Dharmaprakash, K. Byrappa, Characterization of transparent semiconducting cobalt doped titanium dioxide thin films prepared by sol–gel process. J. Mater. Sci. Mater. Electron. 0, 1–9 (2017). CrossRefGoogle Scholar
  15. 15.
    S. Venkatachalam, Y. Iida, Y. Kanno, Preparation and characterization of Al doped ZnO thin films by PLD. Superlattices Microstruct. 44, 127–135 (2008). ADSCrossRefGoogle Scholar
  16. 16.
    M.Z. Musa, K.A. Kasbi, A.A. Aziz, M.S.P. Sarah, M.H. Mamat, M. Rusop, Aluminium doping of titanium dioxide thin films using sol–gel method. Mater. Res. Innov. 15, s137–s140 (2011). CrossRefGoogle Scholar
  17. 17.
    J.E. Lee, S.M. Oh, D.W. Park, Synthesis of nano-sized Al doped TiO2 powders using thermal plasma. Thin Solid Films. 457, 230–234 (2004). ADSCrossRefGoogle Scholar
  18. 18.
    N.D.M. Said, M.Z. Sahdan, A. Ahmad, I. Senain, A.S. Bakri, S.A. Abdullah, M.S. Rahim, Effects of Al doping on structural, morphology, electrical and optical properties of TiO2 thin film, 30130 (2017) 30130.
  19. 19.
    M. Pal, U. Pal, J.M.G.Y. Jiménez, F. Pérez-Rodríguez, Effects of crystallization and dopant concentration on the emission behavior of TiO2:Eu nanophosphors. Nanoscale Res. Lett. 7, 1 (2012). ADSCrossRefGoogle Scholar
  20. 20.
    G. Kaur, A. Mitra, K.L. Yadav, Pulsed laser deposited Al-doped ZnO thin films for optical applications, Prog. Nat. Sci. Mater. Int. 25 (2015) 12–21.
  21. 21.
    B. Rajesh Kumar, T. Subba Rao, AFM studies on surface morphology, topography and texture of nanostructured zinc aluminum oxide thin films. Dig. J. Nanomater. Biostruct. 7, 1881–1889 (2012)Google Scholar
  22. 22.
    Q. Feng, Y.X. Yue, W.H. Wang, H.Q. Zhu, First-principles study on anatase TiO2 (101) surface adsorption of NO. Chin. Phys. B. 23, 1–8 (2014). CrossRefGoogle Scholar
  23. 23.
    T. Sekiya, S. Ohta, S. Kamei, M. Hanakawa, S. Kurita, Raman spectroscopy and phase transition of anatase TiO2 under high pressure. J. Phys. Chem. Solids 62, 717–721 (2001). ADSCrossRefGoogle Scholar
  24. 24.
    B. Karunagaran, K. Kim, D. Mangalaraj, J. Yi, S. Velumani, Structural, optical and Raman scattering studies on DC magnetron sputtered titanium dioxide thin films. Sol. Energy Mater. Sol. Cells. 88, 199–208 (2005). CrossRefGoogle Scholar
  25. 25.
    O. Ostroverkhova, Organic optoelectronic materials: mechanisms and applications. Chem. Rev. 116, 13279–13412 (2016). CrossRefGoogle Scholar
  26. 26.
    A. Boutlala, F. Bourfaa, M. Mahtili, A. Bouaballou, Deposition of Co-doped TiO2 thin films by sol–gel method. IOP Conf. Ser. Mater. Sci. Eng. 108, 12048 (2016). CrossRefGoogle Scholar
  27. 27.
    K.M. Sandeep, S. Bhat, S.M. Dharmaprakash, Structural defects and photoluminescence studies of sol–gel prepared ZnO and Al-doped ZnO films. Appl. Phys. A. 122, 975 (2016). ADSCrossRefGoogle Scholar
  28. 28.
    S. Kim, G. Nam, H. Park, H. Yoon, S. Lee, J.S. Kim, Effects of doping with Al, Ga, and in on structural and optical properties of ZnO nanorods grown by hydrothermal method, 34 (2013) 1205–1211Google Scholar
  29. 29.
    A.S. Hassanien, A.A. Akl, Influence of composition on optical and dispersion parameters of thermally evaporated non-crystalline Cd50S50−xSex thin films. J. Alloys Compd. 648, 280–290 (2015). CrossRefGoogle Scholar
  30. 30.
    E.R. Shaaban, M. El-Hagary, E.S. Moustafa, H.S. Hassan, Y.A.M. Ismail, M. Emam-Ismail, A.S. Ali, Structural, linear and nonlinear optical properties of co-doped ZnO thin films. Appl. Phys. A. 122, 20 (2016). ADSCrossRefGoogle Scholar
  31. 31.
    A.A. Ahmad, A.M. Alsaad, B.A. Albiss, M.A. Al-Akhras, H.M. El-Nasser, I.A. Qattan, Optical and structural properties of sputter deposited ZnO thin films in relevance to post-annealing and substrate temperatures. Thin Solid Films. 606, 133–142 (2016). ADSCrossRefGoogle Scholar
  32. 32.
    K.A. Salman, Z. Hassan, K. Omar, Effect of silicon porosity on solar cell efficiency. Int. J. Electrochem. Sci. 7, 376–386 (2012)Google Scholar
  33. 33.
    J. Tasseva, R. Todorov, T. Babeva, K. Petkov, Structural and optical characterization of Ag photo-doped thin As40 S60−x Sex films for non-linear applications. J. Opt. 12, 65601 (2010). CrossRefGoogle Scholar
  34. 34.
    T.S. Senthil, N. Muthukumarasamy, S. Agilan, M. Thambidurai, R. Balasundaraprabhu, Preparation and characterization of nanocrystalline TiO2 thin films. Mater. Sci. Eng. B. 174, 102–104 (2010). CrossRefGoogle Scholar
  35. 35.
    B. Choudhury, M. Dey, A. Choudhury, Shallow and deep trap emission and luminescence quenching of TiO2 nanoparticles on Cu doping. Appl. Nanosci. 4, 499–506 (2014). ADSCrossRefGoogle Scholar
  36. 36.
    H. Kang, J. Kim, J. Kim, S. Lee, Optical property and Stokes’ shift of Zn1−xCdxO thin films depending on Cd content. J. Appl. Phys. 99, 66113 (2006). CrossRefGoogle Scholar
  37. 37.
    F.J. Serrao, K.M. Sandeep, S.M. Dharmaprakash, Annealing-induced modifications in sol–gel spin-coated Ga:ZnO thin films. J. Sol-Gel. Sci. Technol. 78, 438–445 (2016). CrossRefGoogle Scholar
  38. 38.
    O. Gençyilmaz, F. Atay, İ Akyüz, The effect of Co doping on ZnO films: structural, morphological characterization and hall effect measurements. J. Nanoelectron. Optoelectron. 10, 799–805 (2015). CrossRefGoogle Scholar
  39. 39.
    A. Kotbi, B. Hartiti, S. Fadili, A. Ridah, P. Thevenin, Some physical parameters of CuInGaS2 thin films deposited by spray pyrolysis for solar cells. Appl. Phys. A. 123, 379 (2017). ADSCrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of PhysicsMangalore UniversityKonajeIndia
  2. 2.Department of PhysicsBearys Institute of TechnologyMangaloreIndia
  3. 3.Department of PhysicsKarnatak UniversityDharwadIndia

Personalised recommendations