A spectroscopic study on the luminescence of Er in porous silicon

We report a spectroscopic study on the photoluminescence (PL) of erbium implanted into porous silicon (Er:PSi). Two different porous Si samples were implanted with a dose of 1×10¹⁵Er/cm² at 380 keV and annealed at 650°C for 30 min under identical conditions. Both samples exhibited Er³⁺ luminescence at 1.54 μm, which was quenched by less than a factor of two between 15 K and room temperature. Visible PL studies of Er implanted and annealed porous Si samples showed broad spectra which peaked at ∼700 nm for sample A and peaked at ∼660 nm for sample B. Sample A showed a four times stronger Er³⁺ luminescence than that observed from sample B. In contrast, temperature quenching of the Er³⁺ luminescence was found to be similar or slightly weaker from sample B than from sample A. The spectroscopic data will be discussed in terms of the excitation mechanisms of Er³⁺ in porous Si nanostructures.