Structure and photoluminescence of the TiO(2) films grown by atomic layer deposition using tetrakis-dimethylamino titanium and ozone

TiO(2) films were grown on silicon substrates by atomic layer deposition (ALD) using tetrakis-dimethylamino titanium and ozone. Amorphous TiO(2) film was deposited at a low substrate temperature of 165°C, and anatase TiO(2) film was grown at 250°C. The amorphous TiO(2) film crystallizes to anatase TiO(2) phase with annealing temperature ranged from 300°C to 1,100°C in N(2) atmosphere, while the anatase TiO(2) film transforms into rutile phase at a temperature of 1,000°C. Photoluminescence from anatase TiO(2) films contains a red band at 600 nm and a green band at around 515 nm. The red band exhibits a strong correlation with defects of the under-coordinated Ti(3+) ions, and the green band shows a close relationship with the oxygen vacancies on (101) oriented anatase crystal surface. A blue shift of the photoluminescence spectra reveals that the defects of under-coordinated Ti(3+) ions transform to surface oxygen vacancies in the anatase TiO(2) film annealing at temperature from 800°C to 900°C in N(2) atmosphere.