Solution-processed Er³⁺-doped As₃S₇ chalcogenide films: optical properties and 1.5 μm photoluminescence activated by thermal treatment

We report on the optical properties of Er-doped As₃S₇ chalcogenide films prepared using the two step dissolution process utilizing the As₃S₇ glass dissolved with propylamine and by further addition of the tris(8-hydroxyquinolinato)erbium(III) (ErQ) complex acting as an Er³⁺ precursor. The highest PL emission intensity was achieved for As₃S₇ films post-annealed at 300 °C and doped with 1 at% of Er which is beyond the normal Er³⁺ solubility limit of As–S melt quenched glasses.