Dependence of luminescence efficiency on dopant concentration and sintering temperature in the erbium-doped Ba _0.7Sr _0.3TiO ₃ thin films

We found the dependence of luminescence efficiency on Er ³⁺ concentration and sintering temperature in the Er-doped Ba _0.7Sr _0.3TiO ₃ (BST) thin films is governed by crystallinity and ion-ion interaction. X-ray diffraction and Raman studies of the sol-gel prepared samples show that the BST polycrystalline phase occurred when the sintering temperature reaches 700°C, whereas, it becomes worse for temperature above 700°C resulting from phase separation and the Er ³⁺ concentration exceeding 3 mol% due to charge compensation mechanism. The observed green emission reaches maximum at sintering temperature 700°C and 3 mol% Er ³⁺ ions concentration. We also showed the Er dopant does not affect the dielectric property of BST thin films in C-V measurement and the Ba _0.7Sr _0.3TiO ₃ films doped with Er ³⁺ ions may have potential use for electroluminescence devices.