Waveguide Raman spectroscopy of sol–gel Gd₂O₃ thin films

Abstract

Gadolinium oxide films, prepared by the sol-gel process, present waveguiding properties. Their structures were studied by waveguide Raman spectroscopy (WRS) and confirmed using transmission electron microscopy (TEM). The structural evolution of the layers with annealing temperatures from 650 up to 900 • C was investigated. The WRS results and TEM observations were correlated and revealed that crystallization started at 650 • C into the cubic phase. The mean diameter of the crystallites dispersed in the amorphous phase is around 5 nm at this temperature. The film is totally crystallized into the cubic phase at 700 • C. The monoclinic phase simultaneously appears at 800 • C and both phases still co-exist after heat treatment at 900 • C. The films present a heterogeneous structure at 900 • C with grain sizes varying from 5 up to 50 nm and as consequence their waveguiding properties strongly decrease.

Hydrothermal synthesis, characterization and Raman studies of Eu3+ activated Gd2O3 nanorods

“…12(a)) were observed at $137, 308, 389 and 489 cm À 1 . The strong and intense peak at 489 cm À 1 has been assigned as the A g mode, which is attributed as the hexagonal B-type structure of Gd 2 O 3 [16]. The peak at $ 360 cm À 1 (Fig.…”

Novel Gd(OH)3, GdOOH and Gd2O3 Nanorods: Microwave-Assisted Hydrothermal Synthesis and Optical Properties

“…As shown in Figure 1(c), all the diffraction peaks can be perfectly indexed to the hexagonal structure of Gd(OH) 3 (JCPDS 083-2037), monoclinic structure of GdOOH (JCPDS 075-3267) and cubic structure of Gd 2 O 3 (JCPDS 072-6362), respectively [16][17][18][19] . However, the peak widths for Gd 2 O 3 are relatively broader than those observed in the XRD patterns of GdOOH and Gd(OH) 3 , suggesting a smaller crystallite size.…”

“…This behavior is explained by the dehydration process during the phase change, as well as the synthesis method employed, which facilitates the preparation of materials with small particle sizes. Figure 2 shows the representations of the unit cells for the hexagonal Gd(OH) 3 structure with a P63/m space group, the monoclinic GdOOH structure with a P121/m1 space group, and the cubic Gd 2 O 3 structure with an Ia-3 space group [18][19][20] . VESTA program was used for the construction and visualization of these three models 21 .…”

Microstructural Investigation, Raman and Magnetic Studies on Chemically Synthesized Nanocrystalline Ni-Doped Gadolinium Oxide (Gd1.90Ni0.10O3−δ)

“…Generally, Gd 2 O 3 exists in both cubic (C-type) and monoclinic (B-type) structures. Luyer et al 24 studied experimentally and theoretically the Raman spectroscopy of Gd 2 O 3 in both cubic and monoclinic phases. Zarembowitch et al 25 performed experimentally the Raman spectroscopy of monoclinic B-type structure.…”