局部无序型氧硼酸盐光电多功能晶体的生长及结构性能研究

Rare-earth calcium oxyborate Ca4REO(BO3)3 (RCOB) crystal is an important inorganic optoelectric multifunctional material and has recently achieved great success in many different applications, such as laser self-frequency doubling, high-average power frequency conversion and high-temperature piezoelectricity. It has been reported that there is an order-disorder transformation in RCOB crystals with the decreasing of RE3+ ionic radius, which greatly affects the macroscopic thermal, optical and electrical functional properties. Our project aims to grow a variety of differently disordered single crystals using the floating zone technique, for the first time and the heavily doped mixed crystals via the traditional Czochralski method. The corresponding structural disorder and other defects are characterized by a combination of X-ray single-crystal diffraction, X-ray photoelectronic spectroscopy, X-ray absorption spectroscopy and Raman/Infrared spectroscopy. From the first-principles density-functional theory, the origin and effects of disorder have been clarified in detail. A full set of anisotropic physical properties and laser performances in RCOB crystals has been measured and the mechanism between the functional properties and the intrinsic/extrinsic disorder has been explored. A component-structure-property relationship is expected to be established, which believed to serve as a fundamental basis for the growth of high-quality crystals and the further development of novel devices.

稀土钙氧硼酸盐Ca4REO(BO3)3（RCOB）晶体是重要的无机光电多功能材料，近年来在激光自倍频、高功率激光频率转换和高温压电等关键领域获得了重大应用。研究表明，随着RE3+离子半径的缩小，RCOB晶体中出现了从完全有序到局部无序的结构转变，而这种局部无序型结构对晶体的热、光、电等重要功能性质都产生了重大影响。本项目首次利用光伏区法生长一系列具有不同无序度的新型RCOB单晶，此外还采用传统提拉法生长了稀土高掺杂RCOB混晶。结合x射线单晶衍射、x射线光电子能谱、x射线吸收光谱和拉曼/红外光谱等实验手段表征无序结构及其它晶体缺陷，并通过第一性原理密度泛函理论计算，从化学键的角度揭示无序的起源和作用。全面测量RCOB单晶和混晶的各项物理性质和激光性能，分析晶体中固有的本征无序和掺杂导致的非本征无序的影响，得到一定的晶体组成-结构-性质关系，从而为高质量晶体的生长和新器件的研制提供理论依据。

稀土钙氧硼酸盐Ca4REO(BO3)3（RCOB）晶体是重要的无机光电多功能材料，近年来在激光自倍频、高功率激光频率转换和高温压电等关键领域获得了重大应用。研究表明，随着RE3+离子半径的缩小，RCOB晶体中出现了从完全有序到局部无序的结构转变，而这种局部无序型结构对晶体的热、光、电等重要功能性质都产生了重大影响。本项目首次利用光伏区法生长具有不同无序度的新型YbCOB单晶，此外还采用传统提拉法生长了稀土高掺杂RCOB混晶。结合x射线单晶衍射、x射线光电子能谱、x射线吸收光谱和拉曼/红外光谱等实验手段表征无序结构及其它晶体缺陷，并通过第一性原理密度泛函理论计算，从化学键的角度揭示无序的起源和作用。全面测量RCOB单晶和混晶的各项物理性质和激光性能，分析晶体中固有的本征无序和掺杂导致的非本征无序的影响，得到一定的晶体组成-结构-性质关系，从而为高质量晶体的生长和新器件的研制提供理论依据。