Crystal growth of rare-earth-doped ternary potassium lead chloride single crystals by the Bridgman method

High optical quality pure and rare-earth-doped ternary-potassium-lead-chloride (KPb₂Cl₅) single crystals have been grown using the Bridgman technique in a two-zone transparent vertical furnace. Combining the chlorination of the melt, to eliminate oxygen impurities, with a horizontal zone-refining, followed by the Bridgman growth itself using sealed silica ampoules, we successfully grew non-moisture-sensitive crystals of a high optical quality. The moisture content in the raw materials determines the quality of the resulting crystals.     

GaSe晶体的掺S生长及性能研究

当生长掺S的GaSe单晶时, 熔体的强烈对流和溶质扩散使得生长出大尺寸的晶体较为困难。本实验采用改进的Bridgman炉, 并结合坩埚旋转技术, 成功生长出了较大尺寸的GaSe_0.89S_0.11单晶体(ϕ20×60 mm³)。采用X射线粉末衍射仪、能谱仪、纳米压痕仪和傅里叶红外光谱仪测量其结构、成分、机械和光学性质。测试结果表明, 质量分数为2.38%的 S掺杂的GaSe晶体(GaSe_0.89S_0.11)没有发生结构相变; 它的机械性能得到了明显的改善, 同时光学性能也得到了一定的提高。     

钨酸铅晶体生长及其组份挥发

本文首次报道了用坩埚下降技术生长钨酸铅（PWO）晶体;研究了提拉和坩埚下降两种技术生长PWO晶体的组份挥发,得到的结果是PbO的挥发速率高于WO₃,并对一组晶体不同部位的X射线发光性能作了研究．     

Effect of hollow pores on the detection characteristics of trans-stilbene crystals grown by vertical Bridgman technique

Bulk crystals of trans-stilbene were grown using Vertical Bridgman Technique with progressive modification of growth parameters. The grown crystals were studied for their performance in time resolution setup with two anti collinear gamma rays from ²²Na sources. The crystals were subjected to optical microscopic and Scanning Electron Microscopic (SEM) studies. The microscopic defects (hollow pores) in the grown crystals and their effect on the detection characteristics are reported.     

铌酸钾锂晶体的生长技术

铌酸钾锂被认为是目前综合性能指数最高的非线性光学晶体,在半导体二极管蓝激光倍频方面有广阔的应用前景。本文综述了用于蓝光倍频的铌酸钾锂晶体生长研究进展,比较了不同生长方法的优缺点,报道了我们在该晶体坩埚下降法生长研究方面的最新成果。     

Transport Properties of Bi_2S_3 Single Crystals

Bi2S3 single crystals were grown by using a modification of Bridgman method. Measurements of the electrical conductivity, Hall effect and thermoelectric power （TEP） were preformed in two crystallographic directions （parallel and perpendicular to the c-axis）. The measurements showed that the electrical conductivity, Hall mobility, and Seebeck coefficient have anisotropic nature. From these measurements some physical parameters were estimated and the crystals showed n-type of conduction mechanism. Also, values of the energy gap were found to be different in the two directions.     

A Comparative Study of Fe1+?? Te1?x Se x Single Crystals Grown by?Bridgman and Self-flux Techniques

Single crystals of Fe_1+?? Te_1?x Se _x (0??x??0.5) were grown via both Bridgman and self-flux techniques. Large crystals of size ?10??50?mm could be obtained with the Bridgman method. The excess of iron, ????0.07, at interstitial sites was observed to deteriorate the superconductivity of the samples. Study of semiconducting and Curie?CWeiss-like behavior indicates that an appearance of a hump for Fe_1+?? Te_0.60Se_0.40 (????0.04) is more pronounced for the self-flux growth than for the Bridgman method. This was observed via measurement of the normal state of resistivity and magnetic susceptibility, which decrease with lower temperature. Furthermore, our results give evidence that the phase with x??0.40 is readily formed in the self-flux method despite the use of various ratios of initial mixtures.     

Growth and characterization of indium antimonide and gallium antimonide crystals

Indium antimonide and gallium antimonide were synthesized from the respective component elements using an indigenously fabricated synthesis unit. Bulk crystals of indium antimonide and gallium antimonide were grown using both the vertical and horizontal Bridgman techniques. Effect of ampoule shapes and diameters on the crystallinity and homogeneity was studied. The grown crystals were characterized using X-ray analysis, EDAX, chemical etching, Hall effect and conductivity measurements. In the case of gallium antimonide, effect of dopants (Te and In) on transport and photoluminescence properties was investigated.     

Growth and properties of benzil doped benzimidazole (BMZ) single crystals

In the present work, we have made an attempt to study the effect of benzil doping on the properties of benzimidazole single crystals. For this purpose we have grown pure and benzil doped benzimidazole single crystals by vertical Bridgman technique. The grown crystals were characterized by various characterization techniques. The presence of dopants confirmed by powder X-ray diffraction (XRD). Crystalline perfection of the grown crystals has been analysed by high-resolution X-ray diffraction (HRXRD). The transmittance, electrical property and mechanical strength have been analysed using UV-vis-NIR spectroscopic, dielectric and Vicker's hardness studies. The relative second harmonic generation efficiency of pure and doped benzimidazole crystals measured using Kurtz powder test.     

Some recent advances in bulk growth of mercury cadmium telluride crystals

The inherent metallurgical problems associated with the HgTe/CdTe pseudobinary alloy system render the standard crystal growth processes inapplicable to the preparation of mercury cadmium telluride crystals for infrared detector applications. A variety of rather nonconventional techniques have been developed to overcome these problems. Two such techniques, viz. asymmetrical Bridgman and horizontal casting for solid-state recrystallization, developed at Solid State Physics Laboratory for the bulk growth of mercury cadmium telluride crystals are reviewed in this communication. Due to the poor thermal conductivity of mercury cadmium telluride melts and solids, and the use of thick-walled quartz ampuoles, it is extremely difficult to obtain a flat solid-liquid interface during Bridgman growth of this material. The technique of asymmetrical Bridgman has been successful in overcoming this problem to a great extent. Solid-state recrystallization has been widely accepted as one of the most successful techniques for obtaining large quantities of acceptable-quality mercury cadmium telluride crystals for infrared detector applications. This is a two-step process—the melt is first quenched to obtain a good cast, which is then subjected to a grain-growth annealing. The horizontal casting procedure developed for solid state recrystallization growth has been successful in improving the overall quality and yield of bulk mercury cadmium telluride crystals.     

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.     

A method for the preparation of He3 single crystals at ultralow temperatures

A method for the preparation of He₃ single crystals at ultralow temperatures is proposed. The method is based on the shift of the melting curve when a magnetic field is applied. With the use of the proposed technique, it is thought possible to grow single crystals by the Bridgman or the zone-melting method. A trial of this method is being planned and the results will hopefully be published soon.     

Growth of lead molybdate crystals by vertical Bridgman method

The growth of PbMoO₄ crystals by the modified Bridgman method has been reported in this paper. The feed material with strict stoichiometric composition is desirable for the Bridgman growth of the crystals. The continuous composition change of the melts during growth can be avoided because the volatilization of melts is limited by sealed platinum crucibles. By means of the optimum growth parameters such as the growth rate of < 1.2 mm/h and the temperature gradient of 20 ∼ 40°C/cm across the solid-liquid interface under the furnace temperature of 1140 ∼ 1200°C, large size crystals with high optical uniformity were grown successfully. The distribution of Pb and Mo concentration along the growth axis was measured by X-ray fluorescence analysis. The single crystallinity of the grown sample was evaluated by the double-crystal X-ray rocking curve. The transmission spectra were measured in the range of 300–800 nm at room temperature.     

Cd0.96Zn0.04Te单晶生长及晶体成分偏析

采用常规Ｂｒｉｄｇｍａｎ法和ＡＣＲＴ－Ｂ法进行Ｃｄ０．９６Ｚｎ０．０４Ｔｅ晶体生长实验。结果表明：ＡＣＲＴ产生的强迫对流在很大程度上消除了侧壁形核，有利于获得大的晶体；ＡＣＲＴ的加入提高了有效分凝系数ｋｅｆｆ，使其向平衡分凝系数ｋｅｑ趋近，导致轴向的偏析增大。     

ZnO晶体生长新方法研究

基于ZnO-PbF₂高温溶液体系的相关系和析晶行为, 发展了一种通气诱导成核的助熔剂-坩埚下降法生长技术. 通过优化生长参数, 获得了尺寸为φ25mm×5mm的ZnO晶体. 该晶体具有纤锌矿结构, 晶格常数a=0.3252nm, b=0.5209nm. X射线定向确认其择优取向生长方向为[0001]. 实验结果表明, 助熔剂-坩埚下降法是ZnO晶体生长的一条新途径.     

Enhanced fluorescence and time resolved fluorescence properties of p-terphenyl crystal grown by selective self seeded vertical Bridgman technique

The fluorescence and fluorescence decay time of a modified Bridgman grown p-terphenyl single crystals have been studied. The fluorescence spectra of selective self seeded vertical Bridgman technique (SSVBT) grown p-terphenyl single crystals exhibit intense peak at 372 nm and a hump at 388 nm. Fluorescence lifetime measured by Time Correlated Single Photon Counting (TCSPC) method for p-terphenyl crystal showed a very short fluorescence decay time (τ) of 3.3 ns.     

退火处理对PbWO4晶体闪烁性能的影响

本文报道了用改进的坩埚下降技术生长ＰｂＷＯ４晶体经退火处理后,对Ｘ射线激发发射谱,透过谱以及抗辐照损伤能力的影响,指出ＰｂＷＯ４晶体在适合的富氧气氛环境和温度制度下经退火处理后,闪烁性能及抗辐照能力明显得到改善。     

退火处理对PbWO4晶体闪烁性能的影响

本文报道了用改进的坩埚下降技术生长PbWO     

Effect of Ionizing Radiation Parameters on the Properties of AgGaS2 Single Crystals

Inorganic Materials - We report X-ray dosimetric characteristics of AgGaS2 single crystals grown by the Bridgman–Stockbarger method. The 298-K X-ray induced conductivity coefficient of the...     

The growth of single crystals of the intermediate phases NiAl and Ni3Al

Single crystals of stoichiometric NiAl, nickel-rich Ni₃Al, and aluminium-rich Ni₃(Al, Ti) have been grown by a modified Bridgman technique; a strain-anneal method has also been used to produce small, single crystals of non-stoichiometric NiAl.