Thin films of TiN were prepared via RF magnetron reactive
sputtering
at various deposition pressures. The characteristics of the plasmas
were measured by optical emission spectroscopy to optimize the conditions
for the deposition of TiN coatings. After deposition, the thin films
were annealed in a closed furnace at several different temperatures,
and revealed the formation of different phases of TiO<sub>2</sub>.
The resulting TiN/TiO<sub>2</sub> thin films showed drastic changes
in their crystal structure, optical properties, and photoelectrochemical
performance. By examining how the deposition pressure and postdeposition
annealing conditions affected the TiN film structure and performance,
samples were prepared to optimize visible light absorption and activity.
A model for the oxidation process was proposed which described the
structural change from TiN to TiO<sub>2</sub> through optical, morphological,
and crystalline characterization. This study has systematically shown
the ability to tailor the optical, crystalline, and photoactive properties
of TiO<sub>2</sub> by tailoring the intrinsic properties of TiN thin
films and subsequent annealing. These results can be utilized for
many solar driven optoelectronic devices
