Observation of temperature-independent internal Er3+ relaxation efficiency in Si-rich SiO2 films

Abstract

Time-dependent photoluminescence measurements of low-temperature-annealed Er-doped Si-rich SiO2 were conducted at sample temperatures 15-300 K. The erbium internal relaxation efficiency from the second (I4 11/2) to the first (I4 13/2) excited state upon luminescence-center-mediated Er3+ excitation is investigated. Despite the observation of temperature-dependent relaxation rates, the erbium internal relaxation efficiency is found to be remarkably temperature independent, which suggests that the internal relaxation efficiency is near unity. Internal relaxation is shown to account for 50%-55% of the I4 13/2 excitation events in the entire temperature range. These results demonstrate that high pump efficiency and stable operation of devices based on this material will be possible under varying thermal conditions. © 2009 American Institute of Physics.