Structural and optical properties of Er3+-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 ErxY2-xTi2O7 was observed while the annealing temperature exceeded 800 °C. The average transmittance of the ErxY2-xTi2O7 thin films annealed at 400 to 900 °C reduces from ∼ 87 to ∼ 77%. The refractive indices and optical band gaps of ErxY2-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).