Dependence of photoluminescence of Bi-doped Y2O3 phosphor thin films on oxygen content in the sputtering atmosphere

Photoluminescence (PL) emission properties of Bi-doped Y2O3 (Bi:Y2O3) phosphor thin films were investigated depending on the oxygen content in the sputtering atmosphere to find out the optimal oxygen content for obtaining Bi:Y2O3 phosphor thin film with strong PL emission intensity. PL emission intensity was greatly increased by adding a small amount of oxygen to the sputtering atmosphere. However, it was gradually decreased with further increasing the oxygen content. This behavior is thought to be due to the variation of crystallinity and surface roughness of the film depending on the oxygen content in the sputtering atmosphere. The film crystallinity showed similar behavior to PL emission intensity and the surface roughness except the case of Ar only was also decreased gradually with increasing the oxygen content. Density of point defects such as oxygen vacancy and interstitial in the film was expected to be changed according to the oxygen content in the sputtering atmosphere and also this change was considered to have an effect on the PL emission intensity of the Bi:Y2O3 film. In this work, Bi:Y2O3 phosphor thin film with the strongest PL emission intensity could be fabricated with the oxygen content of 10% in the sputtering atmosphere.