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Diffusivity of Er3+ into LiNbO3 as a function of stoichiometry.
- Source :
- Journal of Applied Physics; Jan2009, Vol. 105 Issue 2, pN.PAG, 7p, 1 Chart, 5 Graphs
- Publication Year :
- 2009
-
Abstract
- Diffusivity of Er<superscript>3+</superscript> into LiNbO<subscript>3</subscript> crystal has been studied as a function of Li<subscript>2</subscript>O content and crystal orientation. The Li<subscript>2</subscript>O content in single-crystal LiNbO<subscript>3</subscript> plates was adjusted by Li-rich vapor transport equilibration (VTE) technique. Five X-cut and five Z-cut congruent substrates were VTE treated at first at 1100 °C for different durations ranging from 6 to 74 h, and then were subjected to a special post-VTE anneal procedure at the same temperature for 60 h to obtain homogeneous Li<subscript>2</subscript>O content. The Li<subscript>2</subscript>O content was determined from the measured fundamental optical absorption edge. Its homogeneity is verified by measuring the optical absorption edge as a function of the crystal thickness. After the composition characterization, the substrates were coated with 45 nm thick Er film and annealed at 1130 °C for 40 h in argon atmosphere. The Er<superscript>3+</superscript> profile was analyzed by secondary ion mass spectrometry. The results show that the Er<superscript>3+</superscript> diffusivity decreases monoexponentially with the increase in the Li<subscript>2</subscript>O content in both cases of X- and Z-cut. As the Li<subscript>2</subscript>O content is increased from the congruent point (48.4 mol %) to the near-stoichiometric composition (∼49.9 mol %), the diffusivity decreases from 0.107 (0.072) to 0.017 (0.018) μm<superscript>2</superscript>/h for the Z (X)-cut substrate. The diffusion shows considerable anisotropy for the lower Li<subscript>2</subscript>O content and the diffusivity in a Z-cut substrate is larger. The anisotropy weakens gradually with the increase in the Li<subscript>2</subscript>O content, and the diffusivities in the X- and Z-cut substrates ultimately tend to a same value (∼0.02 μm<superscript>2</superscript>/h) at the Li-rich phase boundary. After the Er diffusion procedure, endface coupling experiment was carried out to check if a planar waveguide layer was formed near the Er-diffused surface due to the Li outdiffusion. The results show that the Li outdiffusion did not accompany the Er diffusion procedure. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00218979
- Volume :
- 105
- Issue :
- 2
- Database :
- Complementary Index
- Journal :
- Journal of Applied Physics
- Publication Type :
- Academic Journal
- Accession number :
- 36339452
- Full Text :
- https://doi.org/10.1063/1.3065483