Band-to-band and direct optical excitation of Er in silicon: Comparison of kinetics, temperature dependence of erbium PL

Photoluminescence excitation spectra of erbium ions in the epitaxial Si:Er/Si structures have been measured in a wide range of excitation wavelengths (λex=800-1580 nm) including the range of direct optical excitation of Er (λex=1460-1580 nm). The temperature quenching of erbium PL have been compared for the regimes of direct optical excitation and excitation by photo-generated carriers in silicon matrix. It has been demonstrated that in case of direct optical excitation of Er ions the temperature quenching of Er PL was much weaker than under band-to-band pumping and the major processes of erbium non-radiative deexcitation such as Auger-deexcitation with equilibrium free carriers and 'back-transfer' are substantially suppressed.