Room-temperature photoluminescence excitation spectroscopy of Er3+ ions inEr- and (Er plus Yb)-doped SiO2 films

We apply photoluminescence excitation spectroscopy to study the efficiency of excitation at 960-990 nm of the 1.54 mu m emission of erbium implanted i nto SiO2 films thermally grown on silicon for a range of Er and Yb concentr ations. We show that, in silica films doped solely with Er, the concentrati on of Er should be lower than 10(20) cm(-3) to prevent efficient concentrat ion quenching of the emission. It is shown that the Yb/Er concentration rat io of 1-2 is optimum for the dopant densities of 1-2x10(20) cm(-3), whereas 10(21) cm(-3) results in quenching of the emission due to energy losses wi thin the Yb subsystem. (C) 1999 American Institute of Physics. [S0003-6951( 99)02840-5].