EXCITATION OF ER3+ IONS IN SILICON DIOXIDE FILMS THERMALLY GROWN ON SILICON

We investigate photoluminescence (PL) and photoluminescence excitation spectroscopy of Er3+ ions implanted into SiO2 films thermally grown o n silicon wafers. We show that at 10 K the Er3+ PL excited with the 51 4.5 nm line of an Ar laser is limited by the total number of Er ions, whereas at resonant excitation within the 960-1000 nm range the PL eff iciency is rather concentration limited. Some samples were codoped wit h Yb3+ ions to study sensitization of the 4f-4f PL of Er3+ ions. At re sonant excitation the presence of Yb leads to an enhancement of the Er 3+ PL only at dilute Er concentrations. (C) 1998 American Institute of Physics. [S0003-6951(98)03446-9].