PHOTOLUMINESCENCE OF SEMICONDUCTING ZINC-OXIDE CONTAINING RARE-EARTH IONS AS IMPURITIES

The photoluminescence of zinc oxide sintered at 1100°C and doped with rare earths (Tm3+, Ho3+, Nd3+ and Er3+) has been investigated under such excitation conditions (around 390 nm) where the light is principally absorbed by ZnO. Contrary to previous reports, no emission from the rare earth could be observed and only the luminescence of the semiconducting substrate in which the rare earth put the fingerprint of its absorption has been characterized. Such partial reabsorption of the green emission of ZnO by the rare earth has been verified by the diffuse reflectance spectra of the same samples which show the same typical fine structures. Only holmium presents an emission when excited in its absorption band at 450 nm; no light emitted above 900 nm could be characterized in the present study. © 1990.