共查询到20条相似文献，搜索用时 15 毫秒
1.
Kunpeng Wang Wentao Yu Jianxiu Zhang Hongyan Xu Jiyang Wang Xian Zhao Changshui Fang 《Journal of Applied Crystallography》2005,38(4):675-677
High‐quality CePO4 single crystals (monazite) were grown by the flux TSSG (top‐seeded‐solution growth) slow‐cooling method. The X‐ray powder diffraction pattern shows good crystalline quality of the crystals and the various peaks were assigned. The unit‐cell parameters were calculated using the DICVOL90 and TEROR computer programs. The concentrations of all elements in the crystals were measured by electron probe microanalysis. Growth habits were deduced by the Bravais–Friedel Donnay–Harker (BFDH) method and macro‐defects in the crystals are discussed. An infrared spectrum of the crystal was recorded in the frequency range of 300 to 1600 cm−1 and all vibration frequency peaks were assigned. 相似文献
2.
I. Bhaumik S. Ganesamoorthy R. Bhatt A. K. Karnal R. Sundar V. K. Wadhawan 《Crystal Research and Technology》2006,41(12):1180-1183
The presence of an impurity like rhodium in the platinum crucible used for the growth of KTiOPO4 (KTP) single crystals can have severe consequences in the performance of devices made from these crystals. In the present study the effect of rhodium incorporation has been investigated. Rhodium‐incorporated KTP crystals have a lower ionic conductivity (1.3 × 10–7 S/cm at 100 kHz) than pure KTP crystals (3.5 × 10–6 S/cm at 100 kHz) along the c‐axis. And the optical absorption in the green‐wavelength regime leads to a detrimental effect on their SHG performance. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
3.
Takashi Horiuchi Lei Wang Atsushi Sekimoto Yasunori Okano Takuya Yamamoto Toru Ujihara Sadik Dost 《Crystal Research and Technology》2019,54(5)
The top‐seeded solution growth method is a promising technique for growing high‐quality silicon carbide single crystal. Some inherent issues in this growth process, such as morphological instability, polycrystalline growth, and low growth rate, should be clarified. A high temperature difference between the seed and the crucible wall in this system is needed to enhance growth. However, such a high temperature gradient makes the radial growth rate profile non‐uniform due to the effect of Marangoni convection below the seed crystal, which leads to poor crystal quality. In the present work, the effects of crucible size and crucible rotation are numerically investigated to minimize the effect of Marangoni convection. The possibilities of the occurrence of growth‐rate non‐uniformity and undesired impurity incorporation are examined. A smaller crucible (in radius) leads to a more uniform growth rate profile. However, it gives rise to a higher possibility of impurity incorporation. It is also predicted that crucible rotation is ineffective in suppressing the Marangoni flow near the seed edge. This leads to a flow stagnation in the center of the melt, and consequently, it does not enhance the carbon transport below the seed. It also does not reduce the possibility of undesired impurity incorporation. 相似文献
4.
采用顶部籽晶熔盐法,以K2WO4为助熔剂生长出铒、镱共掺钨酸钆钾[Er,Yb：KGd（WO4）2简称Er,Yb：KGW]激光晶体。XRD分析结果表明晶体为低温相Er,Yb：KGW晶体,即β-Er,Yb：KGW晶体。通过差热分析测量,确定其相变温度和熔点分别为1020℃和1080℃。测量了晶体190-2000nm的室温透过光谱,结果表明除980nm的吸收谱带是Er^3＋离子和Yb^3＋离子的共同谱带之外,其余均属于Er^3＋离子。 相似文献
5.
Wenlin Zhang Xiaoqing Wang Guangqiu Shen Dezhong Shen 《Crystal Research and Technology》2012,47(2):163-168
A single crystal of Te2V2O9 with dimensions of 15×15×5 mm3 has been grown by the top‐seeded growth method. Infrared and transmission spectra indicate the transmission cutoff wavelength of Te2V2O9 crystal is about 620 nm in visible region and 6.2 μm in infrared region. In addition, band structure and density of states calculations of Te2V2O9 were carried out using the total‐energy code CASTEP based on density functional theory. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
6.
A. Majchrowski M. T. Borowiec J. Zmija H. Szymczak E. Michalski M. Bara&#x;ski 《Crystal Research and Technology》2002,37(8):797-802
Top Seeded Solution Growth (TSSG) technique has been used to produce Bi12TiO20 (BTO) and some mixed Bi12Ti0.8M0.2O20 single crystals in which Ti was substituted with M=V, Pb or Ga. Pure Bi40Ga2O63 (BGaO) single crystals have been grown, too. Thermal conditions enabling growth of uniform [110] sillenite single crystals with totally flat (110) interface have been found. Influence of composition on spectral characteristics of the BTO mixed crystals has been investigated. 相似文献
7.
碳化硅(SiC)作为第三代半导体材料,不仅禁带宽度较大,还兼具热导率高、饱和电子漂移速率高、抗辐射性能强、热稳定性和化学稳定性好等优良特性,在高温、高频、高功率电力电子器件和射频器件中有很好的应用潜力。高质量、大尺寸、低成本SiC单晶衬底的制备是实现SiC器件大规模应用的前提。受技术与工艺水平限制,目前SiC单晶衬底供应仍面临缺陷密度高、成品率低和成本高等问题。高温溶液生长(high temperature solution growth, HTSG)法生长SiC单晶具有晶体结晶质量高、易扩径、易实现p型掺杂等独特的优势,有望成为大规模量产SiC单晶的主要方法之一,目前该方法的主流技术模式是顶部籽晶溶液生长(top seeded solution growth, TSSG)法。本文首先回顾总结了TSSG法生长SiC单晶的发展历程,接着介绍和分析了该方法的基本原理和生长过程,然后从晶体生长热力学和动力学两方面总结了该方法的研究进展,并归纳了该方法的优势,最后分析了TSSG法生长SiC单晶技术在未来的研究重点和发展方向。 相似文献
8.
底部籽晶法:一种高温溶液晶体生长新方法 总被引：3，自引：2，他引：1
为了从高温溶液中生长非一致熔融的单晶材料,发展了一种叫做\"底部籽晶法\"的新生长方法.通过设计大的垂直温度梯度,解决了助熔剂或高温溶液对籽晶的侵蚀问题;采用后加热系统,有效地控制了晶体的开裂.采用底部籽晶法,成功地生长了新型弛豫铁电晶体(1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3(0≤x≥0.2)、近化学计量比LiNbO3晶体以及非线性光学晶体铌酸钾锂K3Li2-xNb5+xO15+2x(0相似文献
9.
D. Perlov S. Livneh P. Czechowicz A. Goldgirsh D. Loiacono 《Crystal Research and Technology》2011,46(7):651-654
Growth of large β‐barium borate (BBO) crystals of high optical quality has been challenging, even 25 years past its discovery. The best results in terms of size and quality have been demonstrated by means of TSSG (Top Seeded Solution Growth). Nevertheless, the maximum available size of nonlinear optical elements lags behind laser industry requirements. Due to increased size and availability, BBO finally started attracting attention for its favorable Q‐switch properties. Yet, two or sometimes three crystals aligned together are still necessary to achieve the lengths often required for these applications. Material quality, in terms of optical perfection and optical absorption, is still questionable in many instances. Limited boule size still dictates relatively high material cost as well. Thorough analysis of the growth behavior of BBO helped us to develop production processes for large boules utilizing TSSG with pulling. High quality nonlinear optical crystal devices and Q‐switches up to 40 mm in the z‐direction have been enabled. We believe that the above size and quality are currently industry leading. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
10.
首次以LiF-H3BO3为助熔剂,用顶部籽晶法,生长出尺寸为12 mm×13mm×5mm的Ba2B5O9Cl透明单晶.通过热性能分析证实该晶体为非同成分熔融化合物,属于正交晶系,空间群Pnn2,晶胞参数为a=1.1576(2) nm,b=1.1619(2)nm,c =0.66874(13) nm,V=0.8994(3) nm3,Z=4.该晶体中含有BO3和BO3基团,具有三维网状的晶体结构.Ba2B5O9Cl粉末的非线性光学效应约为KDP的3.5倍,同时还进行了红外、漫反射光谱性能的研究. 相似文献
11.
Zhihua Li Ran Zhang Yaohuan Wu Bo Tang Guochun Zhang 《Journal of Applied Crystallography》2015,48(6):1665-1671
The diagram of phase equilibria in the BaB2O4–NaF system has been used to deduce the relationship between the cooling speed (ΔT), the pulling speed (v), the crystal radius (Rs), the slope of liquidus (m), the solution component (x) and the total quantity of melt, namely ΔT = 0.00159Rs2vmx2/G. The theoretical curves of the crystal thickness dependence on cooling rate and pulling rate have also been drawn. Under the guidance of the deduced formulas, the controlled growth of β‐BaB2O4 (BBO) crystals to a desired size has been achieved. A typical as‐grown BBO crystal with dimensions of Ø76 × 33 mm (525.25 g) has been grown successfully by using the high‐temperature top‐seeded solution growth method. The measured optical homogeneity indicates that the as‐grown BBO crystal has high optical quality (Δn≃ 6.9 × 10−6). The experimental curves of the crystal thickness versus the cooling rate and pulling rate were in line with the theoretical curves. The phenomenon of diameter shrinkage in the crystal growth has also been explained according to theory and practice. The theoretical derivation and experimental results provide the rationale for further growth of large BBO crystals with high optical quality. 相似文献
12.
本文以PbO-0.25B2O3为助熔剂,利用顶部籽晶法获得了较大块的Cd3Zn3B4O12单晶.透过率测试结果显示该晶体的紫外截止波长位于310 nm处.利用Kurtz-Perry的方法对晶体的倍频效应进行了测试,结果显示该晶体的粉末倍频效应约为KDP的5倍,且能实现相位匹配.晶体的光损伤阈值约为840 MW(1064 nm,10 ns).该晶体的热分析结果显示Cd3Zn3B4O12晶体在熔点温度以上会产生分解,这也是阻碍高质量大块Cd3Zn3B4O12晶体生长最主要的因素. 相似文献
13.
W. W. Zhou R. Z. Zhuang W. Zhao G. F. Wang L. Z. Zhang J. G. Ma X. Bao F. W. Wang Y. H. Chen 《Crystal Research and Technology》2011,46(9):926-930
Na3Gd2(BO3)3 crystals with dimensions up to 22 × 20 × 5 mm3has been grown from NaBO2 flux by the top‐seeded solution growth (TSSG) method for the first time. Differential scanning calorimetry (DSC) result shows that Na3Gd2(BO3)3 melts incongruently. The infrared spectrum indicates that Na3Gd2(BO3)3 contains characteristic triangular [BO3]3– groups responsible for the nonlinear optical effect. For the as‐grown crystal, the transmittance exceeds 80% in the wavelength range of 315 nm to 2670 nm, and the UV cutoff wavelength is 207 nm. The damage threshold is 0.47 GW cm–2 at 1064 nm. Moreover, Na3Gd2(BO3)3 crystal exhibits an optical second harmonic generation effect which is 1.3 times as large as that of KH2PO4 (KDP). (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
14.
15.
V. I. Ivanenko I. V. Zatovsky N. S. Slobodyanik P. G. Nagornyi V. N. Baumer 《Crystal Research and Technology》2008,43(4):355-361
Zirconium‐doped KTiOPO4 (KTP) crystals were grown using a high temperature flux method in the K2O‐P2O5‐TiO2‐ZrF4 system. The dopant content in the single crystals with general composition KTi1‐xZrxOPO4 (where x = 0 – 0.026) strongly depends on zirconium concentration in the homogeneous melts. AES‐ICP method and X‐ray fluorescence analysis were used to determine the composition of the obtained crystals. Phase analyses of the products were performed using the powder XRD. The structures of KTiOPO4 containing different quantities of Zr were refined on the basis of single crystal XRD data. Applying ZrF4 precursor for zirconium injection into the flux allowed growing the zirconium‐doped KTP crystals at 930–750°C. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
16.
Igor V. Zatovsky Nikolay S. Slobodyanik V. I. Ivanenko Yu. S. Oseledchik V. Yu. Letsenko Tetiana I. Ushchapivska 《Crystal Research and Technology》2016,51(2):178-182
Solid solutions KTi1‐XHfXOPO4 (х = 0.008 – 0.107) possessing the KTiOPO4 structure, have been synthesized in molten system K2O‐P2O5‐TiO2‐HfF4. The crystal growth experiment of Hf‐doped KTP crystal has been reported. The X‐ray powder diffraction data and chemical analysis are also presented. It has been shown that KTiOPO4 crystal structure slightly changes when Hf incorporates into the framework. Transmission/absorption spectra of KTi0.974Hf0.026OPO4 crystals have been recorded. The incorporation of Hf ions shifts the optical absorption edge in the UV‐visible spectrum towards the long‐wavelength region with absorption near 387 nm. 相似文献
17.
A neodymium doped Ca5(BO3)3F single crystal with size up to 51×48×8 mm3 has been grown by the top seeded solution growth (TSSG) technique with a Li2O‐B2O3‐LiF flux. The spectra of absorption and fluorescence were measured at room temperature. According to Judd‐Ofelt (J‐O) theory, the spectroscopic parameters were calculated and the J‐O parameters Ω2, Ω4, Ω6 were obtained as follows: Ω2 = 1.41×10−20cm2, Ω4 = 3.18×10−20cm2, Ω6 = 2.11×10−20cm2. The room temperature fluorescence lifetime of NCBF was measured to be 51.8 μs. According to the J‐O paramenters, the emission probabilities of transitions, branching ratios, the radiative lifetime and the quantum efficiency from the Nd3+ 4F3/2 metastable state to lower lying J manifolds were also obtained. In comparasion with other Nd‐doped borate crystals, the calculated and experimental parameters show that NCBF is a promising SFD crystal. 相似文献
18.
19.
通过顶部籽晶法生长出掺5;和8;Sr2+的La2CaB10O19(LCB)晶体,ICP测得LCB晶体中Sr2+掺入量分别为1.75;和2.02;.XRD证实Sr2+的掺入对LCB晶体晶胞参数的影响较小.摇摆曲线测得Sr2+∶LCB晶体半高宽为36\",表明晶体具有较高质量.Sr2+∶LCB晶体在300～2000 nm波段具有较高的透过率,紫外截止边为172 nm.拟合的色散方程符合Sr2+∶LCB晶体折射率的实验值,理论计算表明Sr2+∶LCB晶体可实现相位匹配,其最短二倍频波长小于LCB晶体. 相似文献
20.
利用X射线衍射和显微激光拉曼光谱研究熔盐法自发结晶的KTP晶体、顶部籽晶熔盐法KTP晶体和水热法KTP晶体的晶胞参数和拉曼光谱特征,分析和比较不同方法生长的KTP晶体的晶体结构与化学键特征峰.研究表明:KTP晶体的晶胞参数与晶体生长方法有关,熔盐法自发结晶的KTP晶体生长过程中降温速率较快,晶胞体积相对较小;熔盐法和水热法KTP晶体中部分拉曼特征峰的位置因生长方法不同呈现一定的差异,水热法KTP晶体在782 cm-1、744 cm-1和515 cm-1处出现的特征峰可视为水热法KTP晶体的标志峰,借此可将其与熔盐法晶体相区分. 相似文献