Improvement of (004) texturing by slow growth of Nd doped TiO2 films

Abstract

Enhancement of optical absorption by modulation of the oxygen flow of TiO2 films deposited by reactive sputteringIn this work, we present preferred (004) texturing of sputter deposited titanium dioxide (TiO 2 ) films on glass substrates as a consequence of Nd doping at very slow growth rate. Nd concentration was varied from 0.0 to 2.0 atomic percent (at. %) in TiO 2 thin films deposited under identical growth conditions, i.e., the growth rate of 0.6 Å /s and at 500 C. At 2 at. % Nd, complete texturing along (004) plane was observed, as indicated by the X-ray diffraction analyses. Morphology of the deposited TiO 2 films from pure to 2 at. % Nd doped TiO 2 films showed faceted to planar growth. Visualization of electrical and structural analysis (VESTA) software revealed that the change in the morphology was due to preferential growth in (004) orientation. Raman spectroscopy highlighted the phonon confinement in the Eg mode, and a red shift was observed due to an increase in the anti-symmetry in bonding with increased Nd concentration. XPS results confirmed the variation in oxygen vacancy concentration along with the reduction of Ti and Nd valance states with the change in the dopant concentration. Our experiments confirmed that the substitution of Nd at Ti sites was responsible for texturing in (004) orientation and this was possible by growing films at a very slow rate. V C 2012 American Institute of Physics. [http://dx.

Controllable nitrogen doping in as deposited TiO2 film and its effect on post deposition annealing

“…However, for N-TiO 2 , the incorporation of nitrogen introduces strain in the lattice and results in the lowest surface energy on the (001) plane. A similar dopant-induced texturing effect was previously observed by Ali et al 24 in neodymium doped TiO 2 film. The different phases that the N-TiO 2 films transform to also imply that the annealing ambient strongly affects the crystallization process.…”

Comparison of the heat-treatment effect on carrier dynamics in TiO2 thin films deposited by different methods

“…This can be caused by stress in TiO 2 thin films which may have resulted from the rapid crystallization upon the heat-treatment. Strong (004) texture has been reported for Nd doped 26 and N doped 27 anatase TiO 2 thin films where dopants have introduced strain in the lattice. For such an unrelaxed TiO 2 , the (001) plane has the lowest surface energy, whereas for relaxed TiO the (101) plane is the most favorable surface 28 .…”

Present and Future of Phase-Selectively Disordered Blue TiO2 for Energy and Society Sustainability

“…Therefore, research is needed to boost light absorption efficiency and block charge recombination to maintain a high exciton dissociation capability. Many attempts have been made to attain a broader range of light absorption by using non-metallic elements (C, N, and S) [ 17 ] and transition metal doping [ 18 , 19 ] to tune the TiO 2 electronic structure. However, only a few researchers have tried to develop advanced TiO 2 by targeting both visible-light absorption and high charge separation efficiency.…”