KDP晶体位错结构及（101）晶面生长机理的研究

发布时间：2018-05-26 18:13

本文选题：KDP晶体生长 + 台阶聚并　；参考：《山东大学》2017年硕士论文

【摘要】：KDP晶体是一种性能优良的非线性光学晶体。当前,KDP晶体已经实现了工业化生产,由大尺寸KDP加工出来的倍频镜头也已经成功的应用于惯性受约核聚变系统。但是,我们对KDP晶体生长的微观机理仍然知之甚少;大尺寸KDP晶体快速生长仍然存在失效率高,晶体质量差等问,促进了对生长机理的研究。针对以上问题,我们对KDP晶体的生长过程中的各种现象进行了表征,并重点研究了 KDP晶体中位错的结构以及KDP晶体的位错生长机制。各个实验内容及结论介绍如下:1,通过蚀刻和光学方法测量位错方向。通过化学腐蚀,可以在晶面位错终止处得到倒三角锥形蚀坑,锥头处即位错端头。切割一定厚度的晶片,通过在上下表面寻找呈现出相同形态分布的蚀坑,可以断定这些蚀坑由同一组位错形成,进而根据几何关系计算出位错方向。实验中,我们获得了 7组可靠的数值,并预测晶体中存在伯氏矢量为[103],[102],[101]的位错。2,台阶聚并现象的表征。(101)晶面对负离子吸附作用显著,通过偏磷酸盐掺杂,在偏磷酸盐钉扎处观察到了台阶聚并现象,台阶的聚并度提高到了原来的2倍以上。3,二维形核现象的表征。在大过冷度的晶体中,发现了二维形核现象。经测量二维核的高度为0.5 nm,与(101)晶面原子层间距一致。二维核没有特定的宏观外形。4,螺位错生长机制的研究。在传统法和快速法生长KDP晶体的过程中,位错生长机制起主要作用。我们表征了位错中心处形成的生长螺旋,发现其形貌成三角形螺旋线,并从(101)晶面原子排列的角度解释了这一形貌形成的原因。我们还发现了生长螺旋可以以多重螺旋的形成存在,通过建立KDP晶体中的位错模型,解释了多重螺旋形成的原因。在我们的实验中,我们为KDP晶体生长的微观过程提供了直观的认识,有助于我们进一步研究KDP晶体生长机理。更多的问题仍有待解决。
[Abstract]:KDP crystal is a kind of nonlinear optical crystal with excellent performance. At present, KDP crystals have been industrially produced, and the Frequency-doubled lenses fabricated by large size KDP have been successfully applied to the inertial reduced nuclear fusion system. However, we still know little about the microcosmic mechanism of KDP crystal growth, and the rapid growth of large size KDP crystal still has high failure rate and poor crystal quality, which promotes the study of the growth mechanism. In view of the above problems, we characterize the various phenomena in the growth process of KDP crystals, and focus on the structure of dislocations in KDP crystals and the growth mechanism of dislocations in KDP crystals. The experimental contents and conclusions are as follows: 1. The dislocation direction is measured by etching and optical methods. By chemical corrosion, the inverted triangular conical pit can be obtained at the end of the dislocation in the crystal plane, and the wrong end is located at the cone. By cutting the wafer with a certain thickness and searching for the etched pits with the same shape distribution on the upper and lower surfaces, it can be concluded that the etch pits are formed by the same group of dislocations, and then the direction of the dislocation is calculated according to the geometric relationship. In the experiment, we obtained 7 reliable values, and predicted the existence of Burroughs vector in crystal is [103], [102], [101] dislocation. 2, characterization of step aggregation phenomenon. At the point of pinning of metaphosphate, the phenomenon of step aggregation was observed, and the cohesion degree of step increased to more than 2 times of the original. The phenomenon of two dimensional nucleation was characterized. Two dimensional nucleation has been found in crystals with large undercooling. The measured height of the two-dimensional nucleus is 0.5 nm, which is the same as the distance between the atomic layers in the crystal plane. There is no specific macroscopic shape. 4. The mechanism of snail dislocation growth is studied. The dislocation growth mechanism plays an important role in the growth of KDP crystals by conventional and rapid methods. We have characterized the growth helix formed at the center of dislocation and found that it is a triangular spiral line and explained the formation of the morphology from the angle of atomic arrangement in the crystal plane. It is also found that the growth helix can be formed as multiple helix, and the reason for the formation of multiple helix is explained by establishing the dislocation model in KDP crystal. In our experiments, we provide an intuitive understanding of the microscopic process of KDP crystal growth, which is helpful to further study the growth mechanism of KDP crystal. More problems remain to be solved.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O614.113;O772

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