Photoluminescence properties of Er-doped β-FeSi2 grown by ion implantation

Photoluminescence (PL) properties of Er-doped β-FeSi2 (β-FeSi2:Er) and Er-doped Si (Si:Er) grown by ion implantation were investigated. In PL measurements at 4.2 K, the β-FeSi2:Er showed the 1.54 μm PL due to the intra-4f shell transition of 4I13/2→4I15/2 in Er3+ ions without a defect-related PL observed in Si:Er. In the dependence of the PL intensity on excitation photon flux density, the obtained optical excitation cross-section σ in β-FeSi2:Er (σ=7×10−17 cm2) is smaller than that in Si:Er (σ=1×10-15 cm2). In the time-resolved PL and the temperature dependence of the PL intensity, the 1.54 μm PL in β-FeSi2:Er showed a longer lifetime and larger activation energies for non-radiative recombination (NR) processes than Si:Er. These results revealed that NR centers induced by ion implantation damage were suppressed in β-FeSi2:Er, but the energy back transfer from Er3+ to β-FeSi2 was larger than Si:Er.