The Higher Energy Components in Ti2p Xps Spectrum of Ga Doped Barium Titanate

Jya-Ler Jou ； Chien-Ming Lei ； Yi-Wei Xu ； Vincent Wang-Chi Yeh

《Chinese Journal of Physics》 50卷6期 (2012/12) Pp. 926-931

https://doi.org/10.6122/CJP.50.926

並列摘要

The X-ray photoelectron spectroscopy was applied to study a series of room temperature stabilised hexagonal barium titanate (h-BaTiO3), which have been synthesized with solid-state reaction method by adding Ga^(3+) ions into the process of producing BaTiO3. The doping levels vary from 5% to 25% (0.05 ≤ x ≤ 0.25). The photoelectron spectra collected at different spots of the samples showed inhomogeneous occurrences of the atomic replacement. The inhomogeneity increases significantly at and beyond 20% of doping levels (x ≥ 0.2). The expected appearance of Ti^(3+) ions, as a result of replacing Ti^(4+) with Ga^(3+), was observed only when the Ga concentration is 20% or higher. In all of the samples we observed unexpected components at higher binding energies than the expected Ti^(4+)2p3/2 and Ti^(4+)2p1/2 peaks in BaTiO3. These components stayed weak until the doping level reaches 20% and higher, and became stronger together with Ti^(3+) components (at lower binding energies than the corresponding Ti^(4+) peaks). These unexpected components may be attributed to the internal compressive stress due to the coexistence of Ba2TiO4 and BaTiO3 as described in [J. Appl. Phys. 95, 219 (2004)].

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