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oe1(光电查) - 科学论文

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?? 中文（中国） ▾

  • The role of carbon in the formation mechanism of F-type centers in α-Al2O3:C,Mg single crystals

    摘要： In this study, an α-Al2O3:C,Mg single crystal was grown using the Czochralski method with graphite resistance heating, Al2O3, MgO, and graphite powder as raw materials. Both the graphite heating unit and the shield served as the carbon source during the growth process. The structure and the optical properties of the crystal were investigated. The as-grown crystal shows a prominent absorption band at 206 nm, 230 nm, and 256 nm. The excitation-emission (EE) spectrum reveals a weak luminescence center (435/510 nm) that is attributed to the F2t (2 Mg). We calculate the concentration of the F-type centers using Smakula’s equation. Using the first principles simulation method, we studied the relation between the C atoms and the absorption properties of the crystal, and we discuss the role of carbon in the formation mechanism of the F-type luminescence centers for a α-Al2O3:C,Mg crystal.

    关键词： Color centers,Al2O3:C,Crystals growth,Mg

    更新于2025-09-23 15:22:29

  • Growth of Structurally Perfect Diamond Single Crystals at High Pressures and Temperatures. Review

    摘要： The investigations performed at high pressures and high temperatures (HTHP crystallization) have permitted clarifying the mechanism of phase transformations and carbon transport in solvent metals for diamond growth and elaborating methods for growing large-size structurally perfect diamond single crystals of types Ib, IIa, and IIb. The findings have provided the basis for the process of production of diamonds for applications in electronics, laser technology, precision machining operations, well drilling tools. The use of a large-volume six-punch high pressure apparatus makes it possible to grow diamond single crystals with a higher efficiency. It is estimated that this apparatus is capable of producing annually at least 1 mln carats of structurally perfect crystals of required types for various applications.

    关键词： diamond single crystals,growth systems,temperature gradient method,high pressure apparatus

    更新于2025-09-10 09:29:36