Effect of titanium doping on conductivity, density of states and conduction mechanism in ZnO thin film
- 38 Downloads
High quality, ~ 120 nm thin ZnO and Ti-doped ZnO (TZO) films were deposited on silicon substrates using magnetron co-sputtering technique. Surface roughness of the films was ~ 2 nm. Ti incorporation effect on the structure, morphology, conductivity, density of states (DOS) and conduction mechanism was investigated in detail. Ti ions were incorporated in the interstitial sites of hexagonal ZnO lattice. Average crystallite size increased from ~ 16.63 to ~ 19.08 nm upon Ti doping in ZnO film. Conduction mechanism changed from overlapping large polaron tunneling (OLPT) for undoped ZnO film to corelated barrier hopping (CBH) for TZO film. The experimental data were fitted theoretically using OLPT and CBH models to calculate frequency and temperature-dependent DOS. An enhancement of ac conductivity and DOS was observed with the doping of Ti in ZnO thin film. Complex modulus study of TZO film revealed transition from long-range mobility to short-range mobility with increase in frequency.
M. A. Rafiq would like to acknowledge Higher Education Commission for financial support under National Research Program for Universities (NRPU Project No 3662). M. A. Rafiq would also like to acknowledge the financial support from Chinese Academy of Sciences Presidents’s International fellowship initiative grant No 2018VTA0002. A. Jamil would like to thank Higher Education Commission for financial support through IRSIP.
- 11.Y.-M. Lu, C.-M. Chang, S.-I. Tsai, T.-S. Wey, Improving the conductance of ZnO thin films by doping with Ti, Thin Solid Films. 447–448 (2004) 56–60. https://doi.org/10.1016/J.TSF.2003.09.022
- 14.Z.-Y. Ye, H.-L. Lu, Y. Geng, Y.-Z. Gu, Z.-Y. Xie, Y. Zhang, Q.-Q. Sun, S.-J. Ding, D.W. Zhang, Structural, electrical, and optical properties of Ti-doped ZnO films fabricated by atomic layer deposition. Nanoscale Res. Lett. 8, 108 (2013). https://doi.org/10.1186/1556-276X-8-108 ADSCrossRefGoogle Scholar
- 15.M. Yilmaz, G. Turgut, Titanium doping effect on the characteristic properties of sol-gel deposited ZnO thin films. Kov. Mater. 53, 333–339 (2015)Google Scholar
- 19.B.D. Cullity, Elements of X-ray Diffraction, 2nd ed., Addison-Wesley, New York 1978Google Scholar
- 30.M. Shunmugam, H. Gurusamy, P. Anand, Devarajan, Investigations on the structural, electrical properties and conduction mechanism of CuO nanoflakes. Int. J. Nano Dimens. 8, 216–223 (2017)Google Scholar
- 36.A. Jamil, M.F. Afsar, F. Sher, M.A. Rafiq, Temperature and composition dependent density of states extracted using overlapping large polaron tunnelling model in MnxCo1 – xFe2O4 (x = 0.25, 0.5, 0.75) nanoparticles. Phys. B Condens. Matter. 509, 76–83 (2017). https://doi.org/10.1016/j.physb.2017.01.005 ADSCrossRefGoogle Scholar
- 37.N. Chakchouk, B. Louati, K. Guidara, Electrical properties and conduction mechanism study by OLPT model of NaZnPO4 compound. Mater. Res. Bull. 99, 52–60 (2018). https://doi.org/10.1016/J.MATERRESBULL.2017.10.046 CrossRefGoogle Scholar
- 42.A.K. Roy, A. Singh, K. Kumari, K. Amar Nath, A. Prasad, K. Prasad, Electrical Properties and AC Conductivity of (Bi0.5Na0.5)0.94Ba0.06TiO3 Ceramic, ISRN Ceram. 2012 (2012) 1–10. https://doi.org/10.5402/2012/854831
- 45.M.A. Diab, N.A. El-Ghamaz, F.S. Mohamed, E.M. El-Bayoumy, Conducting polymers VIII: Optical and electrical conductivity of poly(bis-m-phenylenediaminosulphoxide). Polym. Test. 63, 440–447 (2017). https://doi.org/10.1016/J.POLYMERTESTING.2017.09.001 CrossRefGoogle Scholar