Structural and morphological studies of Nd-doped phosphate thin films deposited by PLD on silicon wafers

摘要

Nd-doped phosphate thin films were obtained by pulsed laser deposition (PLD) technique on silicon wafers using a Nddoped Li_2O-BaO-Al_2O_3-La_2O_3-P_2O_5 bulk target. An excimer laser with 248 nm wavelength was used to ablate the vitreous doped phosphate glass. The oxygen pressure and the substrate temperature were varied during the deposition process as follows: a) high vacuum (3x10~(-6) Torr) and T_s = 20 °C； b） P_(o 2)= 1.5×10~(-3) Torr and T_s = 20 °C； c） high vacuum and T_s = 400 °C and d) P_(o2) = 1.5×10~(-3) Torr and T_s=400 °C. It was investigated the influence of these parameters on the compactness and uniformity of the films. The structural characterization of the films was performed using micro-Raman spectroscopy and; Fourier Transform Infrared spectroscopy (FTIR). The chemical characterization and the morphology of the films were made by Energy Dispersive X-ray spectroscopy (EDX), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). It was noticed that the specific molecular vibrations of the ablated target were reproduced in the fabricated PLD films. The obtained films show good uniformity and well preserved stoichiometry.