M. Elisa, I. C. Vasiliu, B. A. Sava, F. Nastase, C. Nastase, A. Volceanov, V. Dima, S. Stoleriu, M. Eftimie, Structural and morphological characterization of silicophosphate thin films containing Nd3+ ions, Phys. Chem. Glasses: Eur. J. Glass Sci. Technol., B.  51/6 (2010) 309–317.

Title: Structural and morphological characterization of silicophosphate thin films containing Nd3+ ions

Abstract: This work is focused on obtaining and characterizing of SiO(2)-P(2)O(5)-Nd(2)O(3)sol-gel thin films. Structural and morphological information were obtained by Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy, atomic force microscopy (AFM) and scanning electron microscopy (SEM). The preparation of sol-gel films started with tetraethoxysilane (TEOS) as precursor for SiO(2), triethyl phosphate (TEP) as precursor for P(2)O(5) and NdCl(3) as precursor for Nd(2)O(3). The thin films were obtained by spin coating at three rotation speeds: 2000, 3500 and 5000 rpm. The deposition of the films was undertaken one day after the preparation of the precursor sols and the drying of the obtained layers took place in air, at room temperature (RT). FTIR spectra recorded in the 400-4000 cm(-1) range revealed optical phonons characteristic of Si-O-Si, P-O-P, Si-O-P and OH bonds. Raman spectra collected in the 100-4000 cm(-1) range provided evidence of stretching, bending and mixed vibration modes specific to the silicophosphate network as well as to Nd-O bonds. AFM analysis revealed that Nd-doped silicophosphate films were relatively uniform in thickness and chemically homogeneous, these features depending on the spinning rate of the substrate. SEM investigations made on films obtained for three spinning speeds indicated the presence of randomly distributed small units and round micro-units.

Key words:  Sol-Gel Synthesis; Pulsed-Laser Deposition; Planar Wave-Guides; Optical-Properties; P2O5-SiO2.