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助熔剂提拉法生长化学计量比LiNbO3晶体 总被引:5,自引:2,他引:3
利用助熔剂提拉法,分别从掺入11mol;K2O的同成份LiNbO3熔体中和从掺入19mol;*!K2O的化学配比LiNbO3熔体中生长出高质量近化学计量比LiNbO3单晶.对这两种从不同配比熔体中生长的晶体进行光谱分析表明,与同成份比LiNbO3相比较,其紫外吸收边出现明显蓝移,OH红外吸收峰的位置和线宽也都有显著的变化.室温极化反转测试显示,两种晶体的矫顽场分别为4.4kV/mm和0.8kV/mm.根据所得测量结果,估计两种晶体中Li2O的含量分别为49.6mol;和49.9mol;.其中从掺19mol; K2O化学配比LiNbO3熔体中生长出的LiNbO3单晶的Li2O含量已非常接近50mol;的化学配比.进一步优化生长工艺,获得成份均匀、大尺寸化学计量比晶体的工作正在进行中. 相似文献
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由于与GaN晶格失配小(约1.4%),γ-LiAlO2单晶有望成为一种很有希望的CaN外延衬底材料.本文使用提拉法生长出了尺寸达φ45×50mm3的γ-LiAlO2单晶.对该晶体毛坯的各个有代表性的位置作了X射线粉末衍射(XRPD)分析,结果表明仅仅在晶体毛坯的底部生成了一种缺锂相(LiAl5O8).γ-LiAlO2晶体化学稳定性差,在室温时轻微水解.当在空气中于1100℃退火70h,γ-LiAlO2晶体挥发出锂组分,在表面产生缺锂相(LiAl5O8).值得注意的是,在γ-LiAlO2晶体的红外光谱区不存在氢氧根吸收带. 相似文献
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本文采用导模提拉法成功生长了Tb3Sc2Al3O12 (TSAG)晶体,并对所生长晶体进行了物相分析和单晶结构分析,探讨了多晶原料的烧结温度对晶体颜色的影响.Sc3+和Al3+的浓度分布测试表明,导模提拉法能较好地克服因分凝效应引起的Sc3+浓度分布不均,可以生长获得浓度分布均匀的TSAG晶体.磁光性能测试表明,Sc3+掺入对晶体在400~1100 nm波长范围内的磁光性能影响不大,所生长TSAG晶体的费尔德常数仅比Tb3Al5O12 (TAG)晶体低6; ~8;. 相似文献
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Single crystalline and crack free potassium lithium niobate (KLN) single crystals with low Li content were grown by the Czochralski method. The crystal composition can be written as K2.60Li1.17Nb5.44O15 (=K2.95Li1.33Nb6.17O17) which contain relatively fewer Li ions than ferroelectric K3Li2Nb5O15 crystals. All experimental results show that the deficiency of the Li ions in the KLN crystals strongly influences their physical properties. Especially, the as‐grown crystals do not indicate any signature for a ferroelectric phase transition in contrast to the ferroelectric K3Li2Nb5O15 crystals. However, due to ionic conduction, the temperature dependence of the dielectric constant of such KLN‐2 crystals show a broad anomaly near 300°C. In addition, the existence of proton defects can be revealed by infrared absorption spectroscopy near 3500 cm‐1 in as‐grown crystals. 相似文献
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G. Müller 《Crystal Research and Technology》2007,42(12):1150-1161
The Czochralski method, i.e. pulling a crystal from the melt, became the most important technology for the production of large semiconductor (Si, GaAs, InP, GaP …) and optical crystals (oxides, CaF2 …). The present status is achieved by a profound analysis of the mechanisms of heat and species transport which are relevant for the stability of the Czochralski growth process and the performance of the growing crystal. It was clearly demonstrated in the last few years that modeling by numerical simulation is an indispensable tool to analyze the Czochralski process and to understand the governing mechanisms. The contribution presents examples of this kind of modeling the Czochralski technique in correlation with experimental investigations in order to illustrate the present status of understanding relevant processing phenomena. Furthermore, it is shown what problems need still to be solved in the future in order to further improve the yield and quality of Czochralski‐grown crystals. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Y. Zheng E. Shi S. Wang Z. Lu S. Cui L. Wang W. Zhong 《Crystal Research and Technology》2004,39(5):387-395
Stoichiometric lithium niobate single crystals with different Li contents have been grown both by the top‐seeded solution growth (TSSG) method from potassium containing flux and by the double crucible Czochralski (DC Cz) method. Spectroscopic properties (e.g. the UV absorption edge, Raman linewidth) and the Curie temperature measurement have been used for the characterization of the crystal composition. The double crucible Czochralski method is found to be suitable for mass production of stoichiometric LiNbO3 with Li content larger than 49.7 mol% and homogeneity of 0.03 mol%. The domain structures and etching morphologies on negative and positive c‐surface were also investigated by chemical etching method. A new domain structure of three‐fold symmetric sectors were observed in near‐stoichiometric LiNbO3 grown by TSSG method. The straight line arrangement hillocks on negative c‐surface and the net‐like arrangement etch lines were observed and explained by stress etching mechanism. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Yexia Fan Chao Xu Shixing Xia Chengxiang Guan Liangcai Cao Qingsheng He Guofan Jin 《Journal of Crystal Growth》2010,312(11):1875-1878
In this paper, Zr:Fe:LiNbO3 crystals with various Li/Nb ratios were grown by the Czochralski method from melts having compositions varying between 48.6 and 58 mol% Li2O. X-ray powder diffraction (XRD), inductively coupled plasma optical emission/mass spectrometry (ICP-OE/MS), ultraviolet–visible (UV–vis) absorption and the infrared (IR) spectrum were measured and are discussed in terms of the spectroscopic characterization. It was found that as the Li/Nb ratio increases in the melt, the Li/Nb ratio in the crystal also increases, the distribution coefficients of Fe and Zr ions decrease, the absorption edge shifts to a shorter wavelength, and the ZrO2 threshold concentration of the samples decreases. 相似文献
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X. H. Zhen W. S. Xu C. Z. Zhao L. C. Zhao Y. H. Xu 《Crystal Research and Technology》2002,37(9):976-982
The pure congruent LiNbO3, Er:LiNbO3 and Zn,Er co‐doped Li‐rich LiNbO3 crystals were grown by Czochralski method. The X‐ray diffraction method and ultraviolet‐visible absorption spectra of the crystals were used to analyze the structure of the crystals. The photo‐damage ability resistance of the crystals was measured. The Zn,Er co‐doped Li‐rich LiNbO3 crystals show a decrease in lattice constant values, a shift in absorption edge of ultraviolet‐visible absorption spectra towards shorter wavelength, and three orders of magnitude increase in photo‐damage resistance compared to congruent LiNbO3 crystal. The intrinsic and extrinsic defects are discussed to explain the enhance of the photo‐damage ability resistance 相似文献
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In this paper, photorefractive properties of Mg:Ce:Cu:LiNbO3 crystals were studied. The crystals doped with different concentration of Mg ions have been grown by the Czochralski method. Mg concentrations in grown crystals were analyzed by an inductively coupled plasma optical emission spectrometry (ICP‐OE/MS). The crystal structures were analyzed by the X‐ray powder diffraction (XRD), ultraviolet‐visible (UV‐Vis) absorption spectra and infrared (IR) transmitatance spectra. The photorefractive properties of crystals were experimentally studied by using two‐beam coupling. In this experiment we determined the writing time, maximum diffraction efficiency and the erasure time of crystals samples with He‐Ne laser. The results showed that the dynamic range (M/#), sensitivity (S) and diffraction efficiency (η) were dependent on the Mg doping concentration, and the Mg(4.58mol%):Ce:Cu:LiNbO3 crystal was the most proper holographic recording media material among the six crystals studied in the paper. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献