Erbium-doped borosilicate glasses containing various amounts of P2O5 and Al2O3: influence of the silica content on the structure and thermal, physical, optical and luminescence properties

The influence of the silica content on several properties of Er-doped borosilicate glasses in the presence of various amounts of P₂O₅ and Al₂O₃ has been investigated. The introduction of P₂O₅ and/or Al₂O₃ are responsible for structural modifications in the glass network through a charge-compensation mechanism related to the formation of negatively-charged PO₄ and AlO₄ groups or through the formation of AlPO₄-like structural units. In this paper, we show that an increase in the SiO₂ content leads to a silicate-rich environment around the Er³⁺ site, resulting in an increased dependence of the Er³⁺ ions optical and luminescence properties on the P₂O₅ and/or Al₂O₃ concentration. The highest emission intensity at 1.5 μm was achieved for the glass with an equal proportion of P and Al in the glass system with 60 mol% of SiO₂.