Excitation of Er3+ emission in Er, Yb codoped thin silica films

Effects of Yb codoping on photoluminescence of Er3+ ions at room temperatur e in SiO2 films thermally grown on silicon are investigated. We demonstrate that for an excitation wavelength of 488 nm Yb ions act as efficient sensi tizers of the I-4(13/2)-I-4(15/2) emission of Er3+ ions. We have found that for the tired dose of Yb the Er3+ intensity is directly proportional to th e Er concentration. Models of the mechanisms responsible for sensitization are discussed. It is shown that the Yb/Er concentration ratio of 0.5-2 is o ptimum for the dopant densities of 2-4x10(20) cm(-3). (C) 2000 Elsevier Sci ence S.A. Ail rights reserved.