Table of Content

15 February 2001, Volume 30 Issue 2

Previous Issue    Next Issue

Study on Micro-crystallization of Cadmium Mercury Thiocyanate (CMTC) Crystal for Laser Diode Frequency Doubling

YUAN Duo-rong;ZHONG Zhen-Wu;ZHANG Ji-guo;DUAN Xiu-lan;GUO Shi-y;WANG Xin-qiang;JIANG Xue-ning;XU Dong;LU Meng-Kai;FANG Qi

2001, 30(2):  113-118. 

Asbtract ( 30 )   PDF (182KB) ( 27 )  

Related Articles | Metrics

Crystallization behavior and habits of cadmium mercury thiocyanate (CMTC) crystal for laser diode frequency doubling in KCl/H2O solvent systems with different KCl concentrations were observed and investigated by means of micro-crystallization experiments.The results show that CMTC crystal exhibits regular crystalline morphologies,homogenous growth speed in different directions and is transparent when the concentration of KCl ranges from 3;-10; and pH value ranges from 3.0-4.3.When pH value ranges from 2.0-3.0,the growth speed along z-axis direction increases and along a-axis direction decreases.Impurities influence greatly crystalline quality and morphology.With time passing and temperature increasing the stability of solution becomes poor.Suitable solution conditions and key factors for CMTC crystal growth and oriented growth were put forward.

Growth and Characterization of CdSe Single Crystals

SHAO Shuang-yun;JIN Ying-rong;ZHU Shi-fu;ZHAO Bei-Jun;SONG Fang;WANG Xue-min;ZHU Xing-hua

2001, 30(2):  119-122. 

Asbtract ( 24 )   PDF (132KB) ( 19 )  

Related Articles | Metrics

High quality CdSe single crystals with excess Cd(10mm in diameter and 45mm in length) were grown using modified sublimation technique,i.e.vertical unseeded vapor growth with multi-step purification.Purification of polycrystalline material and growth of CdSe single crystals were carried on in the same quartz ampoule.The resistivity of the crystal was measured to be of 107—108Ω cm order,and the electron trap densities of 108cm-3.The etch pit patterns of (110)face was reported for the first time.The results showed that this was a new and promising method for growing high quality CdSe single crystals.

Study on Cooperation Effect of Dopant Ions in Growth of KTNNP Crystals

CHANG Xin-An;ZANG He-gui;XIAO Wei-qiang;ZHANG Xiao-hong;JIANG Shao-lin;WANG Xi-min;ZHANG Ke-cong

2001, 30(2):  123-128. 

Asbtract ( 15 )   PDF (173KB) ( 40 )  

Related Articles | Metrics

The Nd3+ and Nb5+ doped KTP(KTNNP) crystals with different dopant concentrations have been grown in high temperature solutions.The lattice parameter of the crystals have been determined by X-ray diffractometer,and the concentrations of the dopants in the crystals have been measured systematically by ICP-AES.The result of the experiments shows that the growth habit and the morphology of KTP crystal have changed greatly and the distribution coefficient of Nd3+ has increased obviously after the doping of Nd3+ and Nb5+ in the crystal growth system,the latter incarnates the cooperation effect of Nb5+ on Nd3+.Otherwise,the volume of the crystal unit cell increase slightly with no regularity after doping.

Growth of Near-stoichiometric LiNbO3 Crystal and Composition Determination

CHEN Xiao-jun;LI Bing;ZHU Deng-song;LI Guan-Gao;CHEN Shao-lin;HUANG Zi-heng;WU Zhong-kang

2001, 30(2):  129-134. 

Asbtract ( 31 )   PDF (202KB) ( 26 )  

Related Articles | Metrics

Lithium niobate(LiNbO3) crystal is a kind of typical non-stoichiometric crystal,and generally used one is congruent crystal with ［Li］/［Nb］ ratio of about 48.6/51.4.In this paper,we report that near-stoichiometric LiNbO3 crystal is grown with Czochralski method from a congruent melt with addition of 11mol; K2O.In comparison with congruent one,the position of absorption edge moves to short wave,Ramam linewidth decreases from 9.4cm-1 to 7.0cm-1 for the E mode(153cm-1) and from 25.5cm-1 to 20.0cm-1 for the A1 mode (876cm-1).Its phase-matching temperature for 1064-532nm second harmonic generation increases from room temperature to 155.5℃ and its OH- infrared absorption band is changed distinctly in shape.The linewidth also becomes greatly narrower.According to these measurements,the lithium oxide content in crystal can be estimated to be about 49.6mol;,which is closed to the ideal stoichiometry of LiNbO3 crystal.

Study on Laser Crystal Nd3+:KGd(WO4)2

TU Chao-Yang;LI Jian-fu;ZHU Zhao-jie;ANG Ding-yuan;WANG Yuan-kang;LUO Zun-Du;J.J.Romero;J.Garcia Sole

2001, 30(2):  135-139. 

Asbtract ( 14 )   PDF (170KB) ( 23 )  

Related Articles | Metrics

A series of KGd(WO4)2 powder samples with different Nd3+ doping concentrations were made and their fluorescent intensities at 1.06μm were measured.The optimal Nd3+ doping concentration has been determined.The liquid temperature curve for the system of Nd3+：KGd(WO4)2-K2WO4 was determined by means of differential thermal analysis(DTA),and large crystals of Nd3+：KGd(WO4)2 with dimensions of up to 50mm have been grown from a K2WO4 flux.From the grown crystal boule,a high-quality laser bulk crystal with dimensions of 5mm×5mm×6mm was cut out,and it's absorption spectrum has been measured.A laser output of 260mW at 1.06μm with a slope efficiency higher than 66; and a laser output of 135mW at 1.3μm with a slope efficiency up to 34.3; were obtained when this crystal was pumped by a Ti-sapphire laser.

Growth and Twin Structure of BPO4 Crystal

SHEN Wei-jun;HU Xiao-bo;FU Pei-zhen;YAO Ji-yong;ZENG Wen-rong;CHEN Chuang-tian;TIAN Yu-lian;JIANG Jian-hua

2001, 30(2):  140-143. 

Asbtract ( 36 )   PDF (132KB) ( 24 )  

Related Articles | Metrics

The new nonlinear optical (NLO) crystal BPO4 has been grown by means of top-seeded solution growth.The transmission topograph of the (001),(101)slice of BPO was taken by transmission synchrotron topography.The structure of the growth twin is investigated.In the transmission synchrotron topograph,the growth twin can be easily seen because its image shifts from the position of main crystal.The formation mechanism was discussed by means of structural analysis

Perspective of Crystal Research in the Past 10 Years

XU Jia-yue

2001, 30(2):  144-148. 

Asbtract ( 32 )   PDF (132KB) ( 34 )  

Related Articles | Metrics

The publications on crystals in the past 10 years were analysed by means of the database of Materials Science Citation Index(MSCI).The number of publications increased fast at a rate of about 1000 papers per year from 1991 to 1999.Laser crystals attracted more attention due to the fast expansion of the information industry.Rapid increase of publications on KDP,SBN and PMN(PZN) shows that these crystals are hot topics in the crystal field recently.The vertical Bridgman technique became more and more important in the past 10 years due to its advantages of low temperature gradient in solid-liquid interface and low production cost.

Growth Kinetics and Mechanism of LFM Crystal

WANG Yan;YU Xi-ling;SUN Da-liang;YIN Shao-tang

2001, 30(2):  149-153. 

Asbtract ( 29 )   PDF (165KB) ( 29 )  

Related Articles | Metrics

Data on growth rates of lithium formate monohydrate (LFM) are determined in-situ at 312.16K.Following Bennema's modification of the BCF surface diffusion model as applied to crystal growth from solution,the values of growth parameters have been calculated and discussed.The results show that the screw dislocation growth is fitted to the growth rate data of (021) and (110) faces of LFM crystals.

Synthesis and Raman Scattering of GaN Nanocrystallite Solids

XU Tao;XU Yan-ping;CAO Yong-ge;LAN Yu-cheng;LI Jian-ye;ZHANG Yue;YANG Zhi;CHEN Xiao-long

2001, 30(2):  154-158. 

Asbtract ( 23 )   PDF (162KB) ( 31 )  

Related Articles | Metrics

A new condensed form of GaN nanocrystallite solid was synthesised by using ammonothermal reaction.The final product is semi-transparrent and with pale yellow color.The average diameter of the composed particles is 12nm.This GaN solid has a wurtzite structure.From Raman scattering of the GaN nanocrystallite solid,the red-shift of E2(high) phonon,broaden of bands and occurrence of new bands (656cm-1 and 714cm-1) were observed,which would be resulted from the nano-size effect of the solid.

Spectral Properties in Semiconductor GaAs—Ga0.65Al0.35As Multi-quantum Well(MQW) Structures and the Possibility of Laser Cooling

ZHANG Xi-tian;ZHANG Wei-Li;GAO Hong;XU Wu;QIN Wei-ping;ZHANG Jia-hua;CHEN Bao-jiu

2001, 30(2):  159-162. 

Asbtract ( 28 )   PDF (116KB) ( 18 )  

Related Articles | Metrics

The spectral properties in GaAs—Ga0.65Al0.35As multi-quantum well (MQW) structures have been developed by using photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopy.The up-conversion of luminescence in GaAs—Ga0.65Al0.35As multi-quantum wells is observed.We put forward the possibility of laser cooling in semiconductor GaAs MQW for the first time.The mechanism of luminescence on the spectrum in GaAs MQW is researched.

Measurement of Electro-optic Coefficients of ADP

LI Zheng-dong;HUANG Xiang-jin;XIONG Ke-ming

2001, 30(2):  163-166. 

Asbtract ( 29 )   PDF (139KB) ( 39 )  

Related Articles | Metrics

The electro-optic coefficients of ADP crystal have been measured at room temperature using DC voltages.The results are γ63＝8.14±0.1×10-12m/V,γ41＝22.2±0.2×10-12m/V at 632.8nm wavelength and γ63＝8.07±0.1×10-12m/V,γ41＝22.9±0.2×10-12m/V at 488nm wavelength.The value of experiment is in good agreement with literature.

Oxidative Degradation of High Quality CVD Diamond

LIU Jing-ming;TANG Wei-zhong;LU Fan-xiu

2001, 30(2):  167-170. 

Asbtract ( 28 )   PDF (160KB) ( 31 )  

Related Articles | Metrics

Studies of the oxidative degradation of high quality diamond have been conducted to better define the limits of application at high temperature.The infrared(IR)and visible optical performance of polished chemical vapor deposition (CVD) diamond films were degraded seriously after heating at 780℃ for 15min,while heating at 780℃ for 3 min produced a little change .Microscopic etched features were revealed by scanning electron microscopy(SEM),atomic force microscopy (AFM),and Talystep surface profiles.Many of the etched features are concentrated at a variety of defects including grain boundaries,surface porosity etc. The results of heating are increasing the surface roughness of CVD diamond films and degradation of the infrared transmittance.

Study on Interface-phase of Crystal Growth

LI Guo-hua;WANG Da-wei;HUANG Zhi-liang

2001, 30(2):  171-177. 

Asbtract ( 22 )   PDF (157KB) ( 30 )  

Related Articles | Metrics

While we were analyzing the proposed theory about the crystal growth,we doubted that the interface phase existed in the process of crystal growth.With this,we had looked for a lot of references connected and analyzed them.We find that the interface-phase does exist in the process of crystal growth and takes a critic role.Therefore,we divide the interface-phase into three co-relative parts:interface layer,adsorptive layer and transitive layer.Base on the above ideal,we demonstrate the role of interface layer,adsorptive layer and transitive layer in the process of crystal growth respectively.Furthermore,we proposal the interface-phase model about the crystal growth.

Study on Elastic and Piezoelectric Properties of GaPO4 Crystal

WANG Yue;SUN Yun-xu;JIANG Yi-jian;YANG Chi

2001, 30(2):  178-184. 

Asbtract ( 33 )   PDF (208KB) ( 28 )  

Related Articles | Metrics

In this paper,the curves of slowness in (100),(010) and (001) for GaPO4 have been plotted.The maximum of acoustic velocities and their directions have also been gained,and compared with that of α-SiO2.Crystal orientation dependence of piezoelectric constant d11 and electromechanical coupling factor k11 have been calculated phenomenologically.The maximum of longitudinal piezoelectric constant d11 and electromechanical coupling factor k11 are obtained.The orientation was also determined.It is found that the d11 and k11 of GaPO4 are much larger than that of SiO2 and the velocity of acoustic wave is smaller than that of SiO2.These results will give certain directions for the use of GaPO4 in piezoelectrical and acoustic-optical devices.

Optical and Electrical Properties of VO2 Thin Films Affected by Valence and Structure

LU Yong;LIN Li-bin;ZOU Pin;HE Jie;WANG Peng

2001, 30(2):  185-191. 

Asbtract ( 30 )   PDF (207KB) ( 20 )  

Related Articles | Metrics

VO2 thin film with good thermochromic properties have been prepared by controlling annealing time and annealing temperature in vacuum.The structural,optical and electrical properties of samples prepared at different parameters have been characterized by using techniques of XRD、XPS、UV-VIS and electrical measurements.The results show that before and after phase transition the resistance of VO2 thin films change about 103 orders,the transmittance of 900nm light change 40; and the switching velocity for absorptivity at 900nm is about 0.2607/min.The structural properties of samples have been improved while the phase-transition properties have declined with the increase of annealing time and annealing temperature.The valence of V and structure of samples have great effect on phase-transition properties of VO2.The best reasonable annealing time and annealing temperature has been got by discussing the effects of annealing time and annealing temperature on the phase-transition point,hysteresis width.

Growth and Phase Diagram of Tb2Fe17 and Tb2(Fe,Si)17 Single Crystals

CHEN JING-LAN;MENG Li-qin;ZHAO De-Qian;GAO SHU-XIA;DU Jiang;WU Guang-heng

2001, 30(2):  192-197. 

Asbtract ( 27 )   PDF (176KB) ( 31 )  

Related Articles | Metrics

Single crystals of rare-earth intermetallic compound of Tb2Fe17 and Tb2(Fe,Si)17 have been grown by CZ method with cold crucible.The phase diagram around Tb2Fe17 has been investigated by various examination methods.It has been found that the phase relation on Tb2Fe17 is not the peritectic,as reported in previous works.A new phase diagram on this compound has been given based on the experimental results,which indicates that the real phase relation on this compound is congruent solidification.This phase relation provides a good intrinsic condition for growing high quality crystal.The X-ray diffraction reveals that the structure of Tb2(Fe,Si)17 become a mixture of Th2Ni17 and Th2Zn17,when the x value is larger than 3.0.The magnetization and the first order magnetization process(FOMP)of the single crystalline samples have been measured,The results indicate that the high quality crystals could be grown from the starting material with stoichiometric composition.Therefore,the magnetic measurement used in the present work will be an effective method for determining the quality of grown single crystals.

Investigation of Chemical Bond Properties and MossbauerIsomerShifts in Magnetoplumbite Type Compound LaMAl11O19(M＝Mg,Fe)

GAO Fa-Ming;LI Dong-Chun;ZHANG Si-Yuan

2001, 30(2):  198-202. 

Asbtract ( 31 )   PDF (172KB) ( 22 )  

Related Articles | Metrics

The chemical bond properties of the magnetoplumbite type compound LaMAl11O19(M＝Mg,Fe) have been studied by using the average band-gap model of the complex crystal chemical bond.The results show that covalency of La-O bond is only 3;,but 4f1 site has very high covalent character in each bond.The covalency for each bond obeys the following order:La-O＜Al(5)-O＜Al(1)-O＜Al(4)-O＜Al(2)-O＜Al(3)-O＜M-O.The anisotropy character in 2d site and 4e site of the crystals is revealed by calculating the chemical bond parameters.Mossbauer isomer shifts of Fe2+ ion in LaFeAl11O19 and Eu3+ ion in LaMgAl11O19 are calculated by using the chemical surrounding facter,h,definited by covalency and electronic polarizability,and the results are in agreement with the experimental values.

Progress of Study on Upconversion Laser & Luminescence Materials

XU Dong-yong;ZANG Jing-cun

2001, 30(2):  203-210. 

Asbtract ( 39 )   PDF (209KB) ( 22 )  

Related Articles | Metrics

This paper briefly presented development history of upconversion materials and four mechanisms leading to upconversion Luminescence.Upconversion laser and luminescence systems were reviewed and the factors affecting luminescence including host materials,sensitized luminescence and single and dual wavelength pump were discussed.

Research on the Defects of PLZST Single Crystal Grown by Flux Method

YAN Qing-feng;SONG Feng-bing;ZHANG Yi-ling;LI Qiang

2001, 30(2):  211-215. 

Asbtract ( 38 )   PDF (184KB) ( 38 )  

Related Articles | Metrics

The defects such as inclusion,splitting,dislocation and dendrite in the PbxLa1-x(Zry Tiz Sn1-y-z)O3(PLZST) single crystal grown from PbO-PbF2 flux by the slow cooling self-seeding technique were discussed in this paper.The forming mechanism of these defects were analyzed and some measures to eliminate the defects were proposed.

Effect of B on Surface Structures and Properties of Synthetic Diamond

GUAN Chang-bin;CUI Zhan-quan;YANG Xue-mei

2001, 30(2):  216-219. 

Asbtract ( 26 )   PDF (145KB) ( 31 )  

Related Articles | Metrics

The effect of B on surface structures and properties of synthetic diamond has been investigated.The results show that on surfaces of diamond synthesized by boronized graphite or boronized catalyst alloy patterns as helix,step,branch and river et al.are seen.The properties of the diamond are not nearly impaired by the patterns.The properties of diamond with B are obviously better than that of diamond without B.And the effects of boronized graphite on the properties of diamond are higher than that of boronized catalyst alloy.