| Rare earth doped luminescent materials have been deeply studied and widely applied in information science, image display, and optical communication et al field due to their special structure of 4f energy level and 4f-5d charge transition state. Furthermore, these studies also accelerate development of basic science. Because of the luxuriant rare earth resource in our country, the developing research of the rare earth application science will be very important for expanding the civil economy and high-new technology property. So the following objects have been studied in this paper:The Raman spectra of Y2O3:Eu have been measured with microscopic Raman spectrometer (RENISHAW H13325) in the temperature region from 83K to 473K. The pump light source is a semiconductor laser with radiation wavelength of 785 nm. And the luminescence spectra of the sample have been measured in the same temperature region by the laser with radiation wavelength of 785 nm. It is found that the Raman spectra have prominently changes with the temperature. Some vibrational modes do not appear until the temperature increases to a certain value. They appear at higher temperatures due to the temperature-induced splitting of degenerate vibrational modes. Besides, the peak position and FWHM of the Raman modes vs. temperature are nonlinear. Different Raman modes follow different functions with temperature which may be induced by the anisotropic properties of crystal lattice. Besides, the fluorescence spectra of the sample broaden with increasing temperature. The FWHM of the fluorescence bands show a linear function dependence of temperature approximately. It could be due to the interaction between electron and phonon strengthenes continuously with temperature increases.In order to study the substitution effect of La for Y, the fluorescence spectra and the Raman spectra of (Y1-xLax)2O3: Eu (x=0,0.05,0.1,0.2,0.3) have been measured. The intensity of samples fluorescence spectra weaken and the width of spectrum lines broaden with x value increasing, because substitution effect of La for Y indues the expansion of lattice and the increase of defects lattice. Along with the increasing of La ion concentration, the expansion makes the lattice in a negative pressure state and the effects become optical absorption centers, which induce the intensity lower and spectrum lines widen. The Raman bands broaden due to La causes lattice distortion of Y2O3 which has been observed as well.The europium-doped yttrium oxide high quality thin films have been grown by pulsed laser deposition (PLD) method and then them studied by XRD, SEM, AFM. The surface of films display that the crystal grains distribution is from disorder tranform to order gradually, then it form island film and flower geometry pattern that was arranged regularly. But the reason we are still in further research.Moreover, the fluorescence spectra of (YxLa1-x)2O3: Eu (x=0,0.05,0.1,0.2) show the spectrum lines intensity decreases and FWHM broaden as the x increase gradually. It may be caused by the substitution Y ion for La. The substitution induces the lattice distortion and more defects that lead to more nonradiative transitions. The Raman bands broaden because the lattice distortion result in the enhancement of anisotropic properties of crystal lattice... |
PDF Full Text Request