Room-temperature PL spectra of the TiO
films annealed at different temperatures in N
atmosphere. The as-grown TiO2 film is amorphous deposited at a substrate temperature of 165°C. The insert is the areal percentages of the red emission band at 600 nm and the green emission band at 515 nm, which are derived from multiple-peak Gaussian fitting of the PL spectra, respectively.