Photoluminescent properties of Ce-doped HfOxNy thin films prepared by magnetron sputtering

The chemical structures and the optical properties of the Ce-doped HfOxNy thin films were prepared by radio frequency (RF) magnetron sputtering and investigated by using X-ray photoelectron spectroscopy (XPS), ultraviolet-visible (UV-vis) absorption spectrophotometer and photoluminescence (PL) spectroscopy. The results showed that the band gap gradually decreased as the nitrogen incorporation content increased from 1.1% to 8.8%. The PL bands located at 380 nm and 465 nm of the sample as-deposited corresponded to the transition from the oxygen vacancy level to valance band and the 5d-4f transition of the trivalent cerium, respectively. The further study revealed that both two PL bands exhibited red shift phenomenon in the NH3-annealed sample, which is due to the decrease of the band gap.