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Tm:YAP晶体生长与缺陷分析

Growth Tm:YAP Crystals and Analysis of the Defects

【作者】 郑卫新

【导师】 刘景和; 徐学珍;

【作者基本信息】 长春理工大学 , 材料学, 2010, 硕士

【摘要】 本论文采用提拉法生长b轴方向的掺铥铝酸钇(Tm:YAP)晶体,通过改善生长过程中各个工艺环节,获得多支尺寸为φ(40-50)mm×(80-100)mm的Tm:YAP晶体,其中部分晶体有开裂、云层等宏观缺陷。讨论了Tm:YAP晶体常见缺陷,并细致研究了晶体开裂、色心和云层的形成机理,得出晶体开裂主要是由于温场不稳定等因素导致的;色心与晶体中离子失位、电荷不平衡等因素有关系;云层不仅和原料不纯、配比有关系还很可能同生长界面曲率和温度梯度有关。通过改善温场设计、生长工艺条件以及分析晶体真空退火前后的吸收光谱和着色等变化,获得高质量的Tm:YAP晶体。通过应力分析、透过光谱、吸收光谱和He-Ne灯等分析手段,系统研究了Tm:YAP晶体生长特性及物理光学特性等。通过分光光度计测试了晶体吸收光谱,并根据吸收系数变化计算了晶体分凝系数、浓度和吸收截面等参数。这些参数对分析2μm Tm:YAP晶体具有参考价值。

【Abstract】 Tm:YAP crystal of b axis were grown by the Czochralski method in this study, Concentrated on the improvement of the all kinds of technics in growth process,and the dimension of the crystal isΦ(40~50) mm×(80~100) mm.However,some of boules contained defects such as split or cloudiness.The defects commonly contained in Tm:YAP crystals were discussed,the defects including crystal cleavage,color center and cloud layer were searched in detail,as a result, the instability temperature field induced crystal cleavage,color center were in contact with some factors such as misplaced ion or nonbalanced charge,cloud layer may not only contact with impurity and mixture ratio of material,but also contact with curvature of growth interface and temperature gradient.Through improvement of the temperature pattern,growth technics and analysis the changes of crystal absorption spectrum and colored,the high quality Tm:YAP have been gained.Growth feature and physical optics character of Tm:YAP single crystals were studied through stress analysis,transmission spectrum,sbsorption spectrum and He-Ne lamp and so on.Absorption spectrum was tested by a lambda 900 spectrophotometer.And the correlative parameters such as separation coefficient,concentration and absorption cross section were calculated.The obtained results are useful for analysis 2μm Tm:YAP crystal.

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