热键合制作Yb:Y3Al5O12/Y3Al5O12复合晶体

采用热键合技术制备了Yb:Y3Al5O12/Y3Al5O12(Yb:YAG/YAG)复合晶体,对复合晶体进行了结构表征和键合质量检测.利用光学显微镜和扫描电镜观察了复合晶体横截面的形貌;在偏光显微镜下观察键合区域的应力,利用干涉条纹来表征复合晶体的光学均匀性;通过红外透过光谱的测量来检测复合晶体的键合质量.实验结果表明:热键合技术制备的Yb:YAG/YAG复合晶体键合界面处无界面缺陷,不存在复合界面空间过渡层,光学均匀性良好.     

新型高效非线性光学晶体ZCTC宏观缺陷的研究

研究了采用蒸发法生长的新型高效紫外非线性光学晶体ZnCd(SCN)4（简称ZCTC）中的溶液包裹物、负晶、开裂、生长条纹、扇形界及直线管道等宏观缺陷的形成。利用光学显微镜观察和分析了这些缺陷的形态、分布规律和形成原因，讨论了消除或抑制ZCTC晶体中缺陷产生的措施。     

提拉法Tm:YAG晶体的生长缺陷研究

采用提拉法(CZ)生长了质量优异的Tm:YAG晶体.部分晶片在1000℃的空气气氛中退火25h.借助光学显微镜、扫描电子显微镜(SEM),结合化学腐蚀法,对Tm:YAG晶体退火前后(111)面的缺陷特征进行了研究. Tm:YAG晶体(111)面的位错腐蚀坑呈三角形. 在偏光显微镜下观察了退火前后Tm:YAG晶体(111)面的应力双折射.同时应用高分辨X射线衍射法测定了晶体的完整性.实验结果表明,长时间空气气氛下高温退火有效降低了晶体中总的位错密度,提高了晶体质量.     

A:Al2O3（A=Cr,Fe,Ni）晶体生长及其缺陷研究

报道了A:Al2O3(A=Cr,Fe,Ni)晶体光学浮区法生长工艺,研究了旋转速率、生长速率对晶体质量的影响,制备出了φ6~8 mm、长度为60~80 mm的A:Al2O3晶体.A:Al2O3晶体的生长方向为<001>方向,X射线双晶摇摆曲线表明A:Al2O3晶体具有良好的晶体质量.通过X射线衍射、扫描电镜、偏光显微镜对晶体中的生长缺陷进行了研究,结果表明,A:Al2O3晶体的主要缺陷为小角度晶界、包裹体和溶质尾迹.研究了A:Al2O3晶体的光谱性能,并对A:Al2O3晶体的介电性能进行了测量,室温下1000 kHz时A:Al2O3晶体表现出较高的介电系数εr(12.1~15.7)和较小的介电损耗tanδ(0.0020~0.0002).     

光学晶体的生长缺陷及分析方法

介绍了光学晶体中的各种生长缺陷,分析了它们的成因以及对于光学晶体性能的影响,并介绍了相关检测方法与手段的特点和局限性.     

籽晶辅助化学气相传输法生长ZnO单晶的特征研究

采用籽晶辅助化学气相传输法生长得到φ32mm ZnO单晶体. X射线衍射表明晶体沿c轴方向生长, 结晶质量较好: 中心部位摇摆曲线半高宽47arcsec, 边缘部分为78.4arcsec. 利用Raman谱、光致发光谱等研究了ZnO晶体退火前后的缺陷和光学性质, 表明经氧气氛退火后晶体缺陷明显减少, 晶体质量进一步提高.     

砷酸钛氧铷晶体的生长、缺陷和物理性能的研究

采用熔盐法,我们已生长出RbTiOAsO4大单晶。不同取向的晶片经腐蚀后,利用光学显微术,观察了晶体中的生长缺陷。并首次研究了其电光性能和电学性能。结果表明RTA晶体不仅是优良的光学倍频晶体,而且是优良的电光晶体。     

Sr2+:α-BBO单晶的性能和缺陷研究

采用提拉法生长了质量优异的掺Sr^2 的α-BBO晶体，XRD结果证实所制备的晶体为高温相，透过率及双折射率分析显示掺Sr^2 不影响α-BBO晶体的光学性能，DSC-TG分析及热膨胀系数的测量表明Sr^2 的掺入对其热学性能的影响不大，同时还对晶体的缺陷进行了初步的研究，研究显示籽品的完整性是影响晶体质量的重要因素。     

KTiOAsO4晶体的生长缺陷研究

研究ＫＴｉＯＡｓＯ₄晶体的生长缺陷,对于改善它的性能和应用前景,有很大的意义．本文利用化学腐蚀光学显微术和同步辐射Ｘ射线形貌术研究了ＫＴｉＯＡｓＯ_４晶体的缺陷,实验结果表明,两种腐蚀剂对于显示ＫＴＡ晶体的表面缺陷效果显著,ＫＴＡ晶体中主要的缺陷有铁电畴、生长层、扇形界、位错和包裹物．讨论了这些缺陷形成的原因。     

Al~(3+)杂质对KDP晶体光学质量影响的研究

用传统降温法和快速生长法生长了Al3+离子掺杂的磷酸二氢钾(KDP)晶体,并对掺杂的KDP晶体的光学质量进行了测试和分析。实验表明,Al3+掺杂对KDP晶体的透光率没有明显的影响,但会使晶体的光散射加剧,光学均匀性和激光损伤阈值下降。     

Optical Sensor for real-time Monitoring of CO(2) Laser Welding Process

An optical sensor for real-time monitoring of laser welding based on a spectroscopic study of the optical emission of plasma plumes has been developed. The welding plasma's electron temperature was contemporarily monitored for three of the chemical species that constitute the plasma plume by use of related emission lines. The evolution of electron temperature was recorded and analyzed during several welding procedures carried out under various operating conditions. A clear correlation between the mean value and the standard deviation of the plasma's electron temperature and the quality of the welded joint has been found. We used this information to find optimal welding parameters and for real-time detection of weld defects such as crater formation, lack of penetration, weld disruptions, and seam oxidation.     

On the characterisation of grown-in defects in Czochralski-grown Si and Ge

High yield processing of advanced integrated devices poses stringent demands on substrate and active device layer quality. Wafers have to be free of electrically active defects and should therefore be free of so called large pit defects and Crystal Originated Particles (COP’s) which can be formed during Czochralski (Cz) crystal growth. These COP’s are surface pits formed by large vacancy clusters and are observed by surface inspection tools based on light scattering as “particles”. They are formed by vacancy clustering during crystal growth. In Cz Si these defects can also be observed inside the bulk of the material by using infra red light scattering tomography and transmission electron microscopy. Recently similar defects were observed on polished Cz Ge wafers using optical and scanning electron microscopy and the same surface inspection tools as used for silicon wafers. In the present paper the characterisation of grown-in voids in Si and Ge using these various techniques is discussed. The observed void size-density distributions are compared with results of the simulation of vacancy incorporation and clustering during the Czochralski growth process.     

Surface damage in machining red brass

The effect of cutting speed, tool rake angle, and wearland length on the nature of the surface generated in machining annealed red brass under unlubricated and lubricated conditions is studied. The machined surfaces are examined using optical and scanning electron microscopy. The machined surfaces were observed to have defects such as microcracks and macrocracks perpendicular to the direction of relative work-tool motion, cavities and plastically deformed regions. The surface damage decreases with an increase in the cutting speed and/or the positive tool rake angle. The presence of lubricant in the cutting region results in a surface of high quality.     

Effect of 8 MeV electron beam irradiation on the structural and optical properties of CeO2 nanoparticles

The effect of 8 MeV electron beam irradiation on the structural and optical properties of cerium oxide nanoparticles was investigated. Ceria nanoparticles were synthesized by chemical precipitation method, and characterized by X-ray diffraction, transmission electron microscopy, ultraviolet–visible, photoluminescence and Raman spectroscopy. Ultraviolet–visible absorption spectra, photoluminescence and Raman spectra of beam irradiated samples were modified, and shifted to blue region, which were attributed to quantum size effect. Systematic observations found that nonstoichiometry, defects and size reduction caused by beam irradiation have great influence on optical band gap, blue shift, photoluminescence and Raman band modifications. Moreover, electron beam irradiation is a suitable technique to enhance the structural and optical properties of nanoceria by controlling the particle size, which may lead to potentially useful technological applications.     

Cd0.9Mn0.1Te晶体生长及其缺陷分析

采用Bridgman法和ACRT-B法生长了两根Cd0.9Mn0.1Te晶锭(简称CMT-B和CMT-A).采用光学金相显微镜和扫描电镜研究了这两种方法生长的晶体中出现的各种缺陷,并分析了其形成机理.采用JEOL-733电子探针测定了两根晶锭中Mn的分布.对比CMT-B和CMT-A两根晶锭,发现ACRT所产生的对流可提高Cd0.9Mn0.1Te晶体的结晶质量.     

三维有序纳米光子晶体的缺陷及其形成机理

通过纳米小球自组装的方法制备获得了三维有序结构的聚苯乙烯（PS）蛋白石光子晶体.利用扫描电子显微镜（SEM）对蛋白石光子晶体的微观形貌进行表征,并利用透射光谱对蛋白石进行光学表征.结果表明,胶体自组装能够形成点缺陷、等边三角线缺陷和等边立方体缺陷,通过对最低能量和机理的探讨,得出导致这些缺陷形成的原因是折射率差异和光子带隙（PBG）位置的蓝移.     

Seal bond characterization of laminated plastic food cups by scanning electron and optic microscopes

Heat seals of laminated semi‐rigid food cups were evaluated to characterize the seal bond. Laminated lidding material was sealed at temperatures of 160–180°C to thermoformed cups. Various seal regions of the cups with different ultrasonic signal strengths (%) were sectioned at the rim and examined using optical and scanning electron microscopes (SEM). Ultrasonic signals were able to pinpoint seal defects; however, the magnitude of the signals did not relate to the actual seal condition or seal quality affected by the sealing process. This was attributed to the very short seal width and non‐parallel surface of the heat seal, which possibly resulted in signal loss by reflection and scattering from the seal surface. C‐scan of ultrasound, SEM and optical microscopic images provided the information that the heat‐sealing process was unstable, due to insufficient and non‐uniform heat‐seal temperature or pressure, misalignment of the sealing jaws or non‐parallel sealing or cutting unit configuration. Copyright © 2004 John Wiley & Sons, Ltd.     

Structural defects as a result of Zn diffusion into CdTe single crystals

The presence of defects in CdZnTe crystals is detrimental for optoelectronic devices fabrication and therefore should be minimized. In this paper we present the characterization of structural defects on the surface and the cross-section of CdTe single crystals that were subjected to high temperature (up to 950 °C) diffusion of Zn. The defects were characterized by various X-ray techniques, optical microscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Quantitative data are obtained, a practical solution for reducing the defects is suggested and some implementations are discussed. Further effort is currently being made to investigate the lattice sites which are involved with the diffused Zn atoms near the surface and in the bulk.