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摘要摘要：本文在对LiYF4晶体的生长、性能与应用等文献充分调研的基础上，介绍了LiYF4晶体的几种生长方法，包括提拉法、μ-PD法、区熔法，重点分析了坩埚下降法的原理、工艺以及特点，并探讨了分凝系数的概念以及平衡分凝系数的计算方法。在实验中，采用预合成的LiF、YF3、NdF3多晶原料，按化学计量比LiF：YF3：NdF3=51.5：47：1.5的比例配比原料，使用铂金坩埚，在空气气氛、无脱氧剂情况下生长了LiYF4晶体。晶体生长在坩埚下降法生长炉内进行，采用DWT一702 精密温控仪控制炉体温度，炉温波动控制在±0.5℃。所得晶体在生长初期是透明的，晶体尾部失透，主要是因为杂质集聚所造成的。生长后对晶体进行了切割、研磨、抛光处理，按照性能测试的要求将晶体切割成3mm厚度的晶片，抛光后的晶体变成1mm厚。使用粉末X射线衍射仪对晶体结构进行表征，对比标准卡片分析了杂相的来源；采用分光光度计测量了透过光谱，晶体在800nm-3000nm范围内具有较高的透过率，可以达到90%以上，在732.8nm、747.0nm和791.6nm处存在主要的吸收峰，可归结为Nd3+离子的能级跃迁，在2505.1nm处的吸收峰，可归结为稀土离子Nd3+吸潮产生的OH-
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离子的吸收峰。 使用Edinburgh Instruments 公司生产的FLS920 全功能型荧光光谱仪 （测试条件为室温、氙灯光源）测试晶体的发光性。结果中产生几个发射峰，均与Nd3+离子掺杂有关，说明Nd3+离子已经进入到LiYF4晶体的晶格，可能占据着Y3+离子的格位。20713
关键词：氟化钇锂晶体；坩埚下降法；晶体生长；掺杂；结构；光谱
Growth and Characterization of Nd:LiYF4 Crystals
Abstract
Abstract：In this paper, we collected the literatures about LiYF4 crystals and presented the
growth techniques for crystal growth of LiYF4 crystals, including Czochralski method,
hydrothermal synthesis method, μ-PD method, zone melting method. The vertical Bridgman
method was introduced in detail. The concept of segregation coefficient and how to calculate it
were discussed. In the experiments, polycrystalline LiF, YF3 and NdF3 were used as raw
materials and they were weighted at its stoichemetric composition as LiF：YF3：NdF3=51.5：
47：1.5. Pt crucible was adopted and crystal growth was carried out at the self-made Bridgman
furnace in air. The furnace temperature was controlled by DWT-702 with an accuracy of ±0.5℃.
As-grown crystal showed transparent in the early stage and opaque in the end stage, which may
be caused by the impurity accumulation. As-grown crystal was oriented, cut and polished into
slices of 1mm thickness for measurement. Powder X-ray diffractometer was measured by XRD
and compared with LiYF4 standard card. The transmission spectrum was measured using
fluorescence spectrometer and the crystal has a good transmittance in the range of
800nm-3000nm.in732.8nm,747.0nm and791.6nm presence at the main absorption peaks were
be attributed toNd3+ ion energy transition. In 2505.1 nm The absorption peaks were attributed to
the vibrations related to Nd3+ and OH-
. Furthermore, the growth defects, such as cracks, bubbles,
were discussed.
KeyWords: LiYF4 crystals； the vertical Bridgman method； crystal growth； doping； structure；
spectroscopy目录
第一章 文献综述. 1
1.1 LiYF4晶体概述...2
1.1.1 晶体结构...2
1.1.2 晶体性能...3
1.1.3 晶体应用领域4
1.1.4 Nd:LiYF4 晶体....5
1.2 晶体生长方法.6
1.2.1 提拉法..7
1.2.2 区熔法..8
1.2.3 坩埚下降法....8
1.3 分凝系数的研究10
1.4 选题依据..12
第二章 实验过程.. 14
2.1 晶体生长过程....14
2.1.1 原料制备.14
2.1.2 晶体生长.14
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