Structural and optical properties of Er-doped Y2Ti2O7 thin films by sol-gel method

Er³⁺-doped Y₂Ti₂O₇ and Er₂Ti₂O₇ thin films were fabricated by sol-gel spin-coating method. A well-defined pyrochlore phase Er_xY_2-xTi₂O₇ was observed while the annealing temperature exceeded 800 °C. The average transmittance of the Er_xY_2-xTi₂O₇ thin films annealed at 400 to 900 °C reduces from ∼ 87 to ∼ 77%. The refractive indices and optical band gaps of Er_xY_2-xTi₂O₇ (x = 0-2) annealed at 800 °C/1 h vary from 2.20 to 2.09 and 4.11 to 4.07 eV, respectively. The ∼ 1.53 μm photoluminescence spectrum of Er³⁺ (5 mol%)-doped Y₂Ti₂O₇ thin films annealed at 700 °C/1 h exhibits the maximum intensity and full-width at half maximum (∼ 60 nm).