کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1516653 1511564 2012 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Optical bandgap and electrical conductivity studies on near stoichiometric LiNbO3 crystals prepared by VTE process
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد مواد الکترونیکی، نوری و مغناطیسی
پیش نمایش صفحه اول مقاله
Optical bandgap and electrical conductivity studies on near stoichiometric LiNbO3 crystals prepared by VTE process
چکیده انگلیسی

Vapour transport equilibrium (VTE) technique was used to prepare near stoichiometric LiNbO3 (NSLN) crystals. Simultaneous occurrence of reduction has been observed during the Li-enrichment that results in the weak absorption bands centred at 1.7, 2.6 and 3.7 eV in the absorption spectrum. Annealing in oxygen atmosphere resulted in decrease in the intensity of these bands. The indirect and direct band-gap energies for NSLN crystals evaluated from absorption studies are reported. The energy of the phonon involved in the indirect transition is ∼85 meV (685 cm−1). Near room temperature ac-conductivity measurements reveal lower conductivity for oxygen annealed NSLN crystal in comparison to as prepared NSLN and CLN specimens. The activation energies for ac-conductivity along the z-direction for NSLN and CLN crystals in the temperature range 500–1100 K are 1.03 eV and 0.96 eV, respectively.


► Evidence of mild reduction is observed in VTE prepared near stoichiometric LiNbO3 (NSLN) crystals.
► The indirect and direct band-gap energies for VTE-NSLN crystals have been reported.
► Reduction induced defects influences the electrical conduction near room temperature.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Physics and Chemistry of Solids - Volume 73, Issue 2, February 2012, Pages 257–261
نویسندگان
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