The structural changes and optical properties of LiNbO3 after Er implantation using high ion fluencies

The structural and compositional changes of LiNbO3 implanted with 190 keV Er+ ions into various crystallographic cuts with fluencies of 1 × 1016 and 5 × 1016 cm−2 were studied. The effect of post-implantation annealing at 1000 °C in oxygen atmosphere was also examined. Concentration depth profiles of implanted erbium, determined by Rutherford Backscattering Spectrometry (RBS), are broader than those from the SRIM simulation. The maximum erbium concentration (of up to 8 at.%) is observed at the depth of about 50 nm, for all crystal cuts. The structure of the implanted layers were characterised by RBS-channelling method. The lower relative number of disordered atoms in the crystalline matrix was observed in the lithium niobate (LN) implanted at a fluence of 1 × 1016 cm−2, where also the preferential position of the erbium in substitutional sites was observed when compared to the randomly distributed erbium in interstitial positions at a fluence of 5 × 1016 cm−2 after the annealing. Surface-morphology changes at the highest implantation fluencies were studied using Atomic Force Microscopy (AFM). Since we were interested in the relation between the structural changes and optical properties, erbium luminescence properties were measured in the region of 1440-1650 nm. The positive effect of post-implantation annealing on the luminescence properties caused by structural recovery was proved.