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X‐Ray, Micro‐Raman, Optical Absorption/Emission Studies of ErNbO 4 Grown by Vapor Transport Equilibration
Author(s) -
Zhang DeLong,
Hua PingRang,
YueBun Pun Edwin,
Siu GueiGu
Publication year - 2007
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2007.01754.x
Subject(s) - raman spectroscopy , crystal (programming language) , materials science , analytical chemistry (journal) , absorption (acoustics) , doping , scanning electron microscope , raman scattering , single crystal , absorption spectroscopy , crystallography , chemistry , optics , optoelectronics , programming language , physics , chromatography , computer science , composite material
Vapor transport equilibration (VTE) treatments were performed on a Y‐cut bulk Er (1.6 mol%)‐doped congruent LiNbO 3 crystal and an X‐cut pure congruent crystal, on one surface of which a 40 nm‐thick film of erbium metal was coated before the VTE treatment. Scanning electron microscope, powder or single‐crystal X‐ray diffraction (XRD), polarized infrared absorption/emission of Er 3+ as well as micro‐Raman spectroscopy were used to study the two VTE crystals. The results are discussed in comparison with a corresponding as‐grown bulk Er‐doped crystal, calcined ErNbO 4 powder, and a locally Er‐doped congruent LiNbO 3 crystal prepared by using the standard Er‐diffusion technique. The experimental results show that the VTE treatment induces the formation of micrometer‐sized ErNbO 4 precipitates with the crystallographic morphology of a flat polyhedron not only on the surfaces of both crystals but also in the bulk of the homogeneously Er‐doped one. The optical absorption and emission studies show that the formation of the precipitates results in substantial spectral changes in both the 0.98 and 1.5 μm regions. The micro‐Raman studies allow to resolve four additional Raman peaks around 800 cm −1 in the E(TO) spectra of the two VTE crystals. These additional Raman peaks are associated with the characteristic vibrations with respect to the NbO 4 3− group. Characteristic XRD, optical absorption, and emission and Raman peaks for identifying the ErNbO 4 phase are proposed. Finally, the formation mechanism and light‐scattering effect of the precipitates are discussed.