Abstract Large diameter Ti-doped sapphire single crystals grown by the Kyropoulos technique along the A-axis, show detrimental light scattering close to the central C-plane. Thermo-luminescence measurements evidence that this defect is associated to a high level of oxygen vacancies. X-ray topography and Rocking Curve Imaging were performed. They show that the dislocation number is very small where scattering occurs, compared to the rest of the crystal, in agreement with results of numerical modelling of thermo-elastic stresses during crystal growth. A model is proposed in order to explain the scattering effect, based on the precipitation of nano-voids from vacancies in the absence of dislocations.

中文翻译：

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在通过 Kyropoulos 技术生长的大直径 Ti:Al2O3 晶体中观察到的散射缺陷的起源

摘要 通过 Kyropoulos 技术沿 A 轴生长的大直径 Ti 掺杂蓝宝石单晶在靠近中心 C 面处显示出有害的光散射。热发光测量证明这种缺陷与高水平的氧空位有关。进行了 X 射线地形图和摇摆曲线成像。他们表明，与晶体的其余部分相比，发生散射的位错数非常小，这与晶体生长过程中热弹性应力的数值模拟结果一致。为了解释散射效应，提出了一个模型，该模型基于在没有位错的情况下从空位中沉淀出纳米空隙。