Structural and Optical Studies of Nano-structure Monolithic Silica-Gel Derived Glasses Containing Nd3+

Abstract

The sol-gel process was applied for the preparation of neodymium (Nd 3+ ) doped silica gel derived glasses. Two different procedures have been studied using two different precursor materials, Tetramethoxy-silane (TMOS) and Tetraethoxy-silane (TEOS), giving silica gel and silica doped with Nd 3+ of type I and type II, respectively. Both type materials were subjected to the same heattreatment temperature. The normal transmission was measured using Fourier Transform Infrared Spectrometer FTIR, Raman analysis and X-ray diffraction (XRD), were carried out to determine the crystal structure of the prepared samples. The prepared samples change from amorphous to ∝-crystoballite phase at higher temperature regardless the two type materials. The crystallite size was found to be as small as 10.4 nm at 1400 o C for pure sample type II. The thermally treated sample microstructures were investigated using scanning and transmission electron microscope. Also DTA and TGA Characteristic techniques were used. The photoluminescence PL measurements for pure sample (type I) heat-treated at 1400 o C shows bands of maximum in the blue green spectral region at 535 and 546 nm accompanied with band of weak intensity at 590 nm. Doped sample (type I) heat-treated at 1400 o C shows new bigger, sharper and intense bands at 875, 889 and 900 nm that were interpreted on the light of 4F3/2 to 4I9/2 transitions of Nd 3+ ion. PL spectra are found to be sensitive to defects such as impurities and E’ centers.