**4.2 Molecular beam epitaxy (MBE) method**

The technique of MBE consist to send one or more molecular jets to a substrate with achieve epitaxial growth (**Figure 7**). It makes it possible to grow nanostructured samples of several cm2 at a rate one atomic monolayer per second. S. Naseem et al. [9] have utilized a Ti electron-beam evaporator and molecular oxygen introduced by a sapphire-sealed leak valve to grown anatase phase TiO2 doped by Co. The growth of TiO2 were controlled by a quartz deposition monitor, and under 399.96 × 10−7 Pa of O2. The 8% cobalt doped TiO2 film has shown 91% degradation

**Figure 6.** *Pulsed laser deposition (PLD) method.*

*Titanium Dioxide Thin Films for Environmental Applications DOI: http://dx.doi.org/10.5772/intechopen.99726*

**Figure 7.** *Molecular beam epitaxy (MBE) method.*

with methylene blue and 88% degradation with Azo dye in 70 min under visible light irradiation exhibiting excellent photocatalytic performance.
