Damage and photoluminescence analysis of RbTiOPO ₄ crystals induced by europium ion implantation

RbTiOPO ₄ crystals were implanted by 400 keV europium (Eu) ions to a fluence of 5 × 10 ¹⁵ ions/cm ² at room temperature. Additive isochronal thermal annealing processes were performed subsequently in Ar atmosphere at 600 °C and 700 °C for 30min. The lattice damage and elemental distributions in the crystals were investigated by Rutherford Backscattering Spectrometry (RBS) and RBS in channelling mode (RBS/C) using 1.4 MeV and 2.1 MeV He ⁺ ions. RBS/C results reveal that Eu implantation led to lattice damage and formation of amorphous layer at the surface. Thermal annealing at 600 °C results in partial damage recovery. The increase of annealing temperature caused further decrease of damage and Eu to diffuse to both sides. The photoluminescence (PL) measurements of Eu implanted RbTiOPO ₄ were performed as a function of annealing temperature, the results indicated the defects induced by implantation reduce the luminescence activation. The luminescence performance was improved significantly after annealing, a strong main peak appeared at 612 nm, and the other peak distributions coincide with the excitation characteristics of Eu. The profiles of PL spectra of annealed sample remain almost the same at temperatures from 5K to 300K, suggesting good luminescence stability of the Eu doped RbTiOPO ₄ crystal.