Growth and crystallization of Cobalt-doped TiO2 alloys: Effect of substrate and annealing temperature

Properties of Metallic and Oxide Thin Films Based on Ti and Co Prepared by Magnetron Sputtering from Sintered Targets with Different Co-Content

“…This means that the addition of cobalt, both in small and large quantities, causes the amorphization of thin films and prevents crystallization. Similar results were obtained by Bohoroquez et al [ 33 ] or Quiroz et al [ 24 ], where Co-doped TiO 2 films prepared by DC magnetron sputtering were completely amorphous. The presence of such crystalline phases as Co 3 O 4 , Ti 4 O 7 , CoTiO 3 and CoTi 2 O 5 usually requires additional annealing at high temperatures (above 450 °C).…”

“…It should be emphasized that even for very thin coatings, the talline nature would be identified in grazing incidence measurements (GIXRD) case of pure titanium-based oxide coatings that were previously manufactured un same conditions (described by the authors elsewhere [31,32]), a well-crystallized structure (composed of crystallites with an average size less than 10 nm) was ob This means that the addition of cobalt, both in small and large quantities, causes th phization of thin films and prevents crystallization. Similar results were obtai Bohoroquez et al [33] or Quiroz et al [24], where Co-doped TiO2 films prepared magnetron sputtering were completely amorphous. The presence of such cry phases as Co3O4, Ti4O7, CoTiO3 and CoTi2O5 usually requires additional annealing temperatures (above 450 °C).…”

“…Such conclusions were also reached in the work of Quiroz et al [ 24 ]. Moreover, other works in the literature on TiO 2 :Co also indicate the effect of fine crystallinity of the grains caused by the addition of cobalt [ 33 , 37 ].…”

“…However, 50 at.% of Co in the target resulted in the manufacturing of less transparent film, with transparency close to 60%. It is noteworthy that the oxide films based on titanium and cobalt are often characterized by a very low level of light transmission [33], and only their additional annealing at a temperature above 500 • C allows to obtain high transparency (usually in the range of 60% ÷ 70%). Based on the transmission characteristics, the Tauc plots (for indirect transitions) were determined, and the optical band gap (Eg opt ) was estimated (Figure 11).…”

A transparent room-temperature ferromagnetic semiconductor on glass: anatase Co-doped TiO2 oriented thin films with improved electrical conduction

“…5,13,28,29 From the viewpoint of applications, replacement of the expensive single crystal substrates with glass substrates is preferred because of their high transparency, processability, flexibility (for ultrathin plates), and low cost. [30][31][32] While thinfilm growth of Ti 1−x Co x O 2−δ on glass substrates was reported previously, [33][34][35][36][37] the AHE and MO effect were observed only for rutile Ti 1−x Co x O 2−δ thin films, where the high resistance hindered the hysteresis loops. 38 Accordingly, it is strongly desired to demonstrate the AHE and MO effect in more conducting anatase Ti 1−x Co x O 2−δ thin films.…”