共查询到19条相似文献,搜索用时 484 毫秒
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钼酸铅单晶生长及其缺陷研究 总被引:2,自引:0,他引:2
本文通过CZ法生长钼酸铅单晶,讨论了温度梯度、拉速、转速等生长参数对晶体质量的影响,分析了晶体开裂、包裹物等宏观缺陷以及位错等微观缺陷的形成机理,并从晶体形态、包裹体和位错密度变化方面探讨了晶体生长参数与晶体缺陷之间的内在关系,从而优化温度梯度等生长参数.温度梯度为20~25℃/cm,晶体转速为28r/min,拉速为1.6mm/h时,生长出的晶体形态完整,无开裂现象,晶体中无气泡包裹体,位错密度明显减小,晶体尺寸达φ40mm×70mm,无散射颗粒,在波长0.42~5.5μm范围内,平均透光率为72.6;. 相似文献
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采用水平定向结晶法(HDS)成功生长出了质量优异的板状蓝宝石晶体.利用光学显微镜,扫描电镜(SEM),并结合化学腐蚀法对生长出的蓝宝石晶体不同位置的样品进行宏观缺陷及微观位错形貌的观测和研究,分析了水平定向结晶法生长蓝宝石晶体的宏观缺陷类型和位错的形貌,探讨了该缺陷在晶体中的分布规律及其形成原因.实验结果发现晶体的宏观缺陷主要包括气泡和包裹体.并结合能谱(EDS)测试包裹体的成分,分析其形成的原因.结果表明块状或絮状的小尺寸包裹体主要是由于C,Si杂质聚集原料中的其它杂质形成;长条形或圆形的大尺寸包裹体是由于Al,O元素的化学计量比严重适配,造成固液界面局部组分过冷形成.结合化学腐蚀法,发现该晶体的位错形貌均为三角型腐蚀坑,并探讨了晶体中位错的形态. 相似文献
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Liquid inclusions and various defects accordingly induced on a nonlinear optical material of CMTC crystal were investigated by atomic force microscopy. Liquid inclusions are chiefly caused by formation of macrosteps, which result from impurity‐induced inhibiting of step growth and meeting of step trains advancing along different directions. Liquid inclusions induce generation of dislocations and even cracks within the crystal by three‐dimensional nucleation growth. Liquid inclusions also provide screw dislocation growth sources, leading to formation of spiral hillock trains with ridged tails. Etching experiments reveal circular hollow cores, indicative of screw dislocation growth, and negative crystals resulting from further crystallization in the liquid inclusions. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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D. Borisova N.V. Abrosimov K. Shcherbachev V. Klemm G. Schreiber D. Heger U. Juda V. Bublik H. Oettel 《Crystal Research and Technology》2016,51(12):742-751
The structure and properties of Czochralski (Cz)‐grown Ge1‐xSix mosaic crystals were investigated using optical microscopy, atomic force microscopy, X‐ray diffraction analysis, microprobe analysis, FTIR and transmission electron microscopy. The role of segregation, form of solid‐liquid interface and dislocation generation in the development of mosaic structure were analyzed and used for optimization of growth parameters such as Si concentration and growth rate. The dislocation density estimated experimentally was compared with the calculated data. Composition fluctuations caused by formation of cellular structure at the interface lead to a local lattice misorientation that is one of the reasons for crystal mosaicity. Model of mosaic structure generation in terms of dislocation density and composition variations is presented. 相似文献
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声光晶体TeO2的生长及缺陷研究 总被引:2,自引:1,他引:1
本文研究了直接TeO2晶体中的主要晶体缺陷形成机理,讨论分析了T eO2单晶生长的工艺参数对晶体缺陷的影响,结果表明:晶体裂缝的主要与温度梯度有关,温度梯度大于20-25℃/cm及出现界面翻转时,易造成晶全的开裂,位错密度增加,晶体中的包裹体主要为气态包裹全,它的形成主要与籽晶的转速和晶体的提拉速率有关,转速15-18r/min,拉速0.55mm/h,固液界面微凹,可以减少晶体中的气态包裹体,晶体台阶由晶体生长过程中温度和生长速度的引起伏引起,当台阶间距较宽时,易形成包裹体。 相似文献
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采用Te溶剂-Bridgman法生长了尺寸为φ30 mm× 60 mm的Cd0.9Mn0.1Te:In晶锭,通过淬火得到了生长界面形貌.测试了晶片在近红外波段的透过率和电阻;采用化学腐蚀的方法观察了晶片中位错,Te夹杂和孪晶界;采用光学显微镜和红外成像显微镜观察了生长界面处附近的形貌.测试结果表明,晶锭中部结晶质量较好的晶片红外透过率达到60%,电阻率达到2.828×1011Ω · cm.位错密度在106 cm-2数量级,Te夹杂密度为1.9×104 cm-2,同时孪晶密度明显低于Bridgman法生长的晶锭.生长界面宏观形貌平整,呈现微凹界面.但由于淬火过程的快速生长,界面微观形貌发生变化,呈现不规则界面,并在界面附近形成富Te相的包裹. 相似文献
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采用导模法生长出六片片状蓝宝石晶体,单片尺寸为350 mm×80 mm×2 mm.通过CGSim模拟软件模拟计算和实验验证,确定了合适的生长温场为横向温梯2.9~4.6 K/mm,生长速度控制在5~10 mm/h之间.对晶体进行双晶摇摆曲线测试,峰强度很高且对称性良好,摇摆曲线的半高宽FWHM=16.946″,证明晶体的结晶完整性很高.采用化学腐蚀法对六片晶体进行位错密度的检测,计算出晶体的位错密度都在103量级,中间晶体位错密度小于两边晶体的位错密度.测试了六片晶体的弯曲强度,最高强度达1583 MPa,中间晶体强度大于两边. 相似文献
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Microdefects such as dislocations and macrocracking should be controlled during the crystal growth process to obtain high-quality bulk single crystals. Solid mechanics and material strength studies on the single crystals are of importance to solve the problems related to the generation and multiplication of dislocations and the cracking of single crystals. The present paper reviews such research activities that comprise the thermal stress analysis during crystal growth process, the dislocation density estimation during crystal growth process, and the cracking of single crystal due to thermal stress. 相似文献