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Abstract: The XPS examination of GdCa4O(BO3)3 revealed that the chemical composition of the crystals grown by the Czochralski method using of the sol–gel GdCOB nanopowder as a starting material have the stoichiometric composition and the smallest carbon contamination in comparison with crystals grown from oxides. [Copyright &y& Elsevier]

Abstract: The praseodymium-aluminium perovskite–praseodymium oxide, PrAlO3–Pr2O3, and praseodymium-aluminium perovskite–praseodymium hexaluminate, PrAlO3–PrAl11O18, eutectics have been recently obtained by the micro-pulling down method. The aim of this work was determination of the chemical composition and electronic structure examination of the above-mentioned eutectics. [Copyright &y& Elsevier]

XPS examinations of NdGaO3 single crystals were performed. A change of the chemical composition was found in wafers cut from the beginning, middle and end part of a crystal grown along the [0 1 1] direction. The existence of core level satellites at low binding energy related to defects was revealed. Unpolished, polished and substrates etched with H3PO4 show a decrease of gallium concentration in relation to a broken surface and to the nominal composition. Annealing of the substrates at different temperatures causes a decomposition due to escape of gallium not only from the surface but from inner parts as well. A comparison of the wafers from the crystals grown along different crystallographic direction reveals changes of the chemical composition and a variable level of defects. This was confirmed by etch pitch density measurements. The above measurements demonstrate the high sensitivity of gallium on processing. [Copyright &y& Elsevier]

The electronic structure measurements of three LSAT single crystals, annealed in hydrogen atmosphere at 900–1400 °C for 1 or 4 h, slowly or rapidly cooled were performed. The existence of core level peak satellites at the lower binding energy site were found. These satellites may be related to the defect states. The crystal annealed at 1400 °C and slowly cooled has the smallest low binding energy satellites. For La 3d, besides the satellites at lower binding energy (SII), the satellites (SI) at higher binding energy to the main peak (M) were detected. It was found that the area peak ratio IM/ISI of the La 3d states is not sensitive to the annealing, polishing or treatment with HCl and HNO3:HF of the wafer surfaces. Contrary to that, the area peak ratio IM/ISII depends on such treatment. The XPS results show that the treatment of the surface with HNO3:HF increases the roughness of the surface which confirmed the AFM results and showed that the surface chemical composition changes with processing. [Copyright &y& Elsevier]