铈掺杂稀土卤化物单晶的处理方法

为了解决铈掺杂稀土卤化物单晶中内部热应力大、难于加工的技术难题,该文提供了一种针对铈掺杂稀土卤化物单晶的原位退火处理方法。利用该方法对尺寸为?25.4 mm×25.4 mm和?76.2 mm×76.2 mm的Ce∶LaBr_3晶体进行退火处理,晶体经过切割、滚圆、研磨、抛光、封装等工艺过程后,均未出现开裂的现象。通过测试以上两种Ce∶LaBr_3器件能量谱图,其能量分辨率分别为2.92%和3.02%,该工艺未对晶体的闪烁性能造成影响。实验结果表明,该文提出的铈掺杂稀土卤化物单晶原位退火处理方法,可有效地消除晶体内部的热应力,并改善其机械性能,这对提高晶体加工成品率具有重要意义。     

65mm级Ce:YSO闪烁晶体研制与闪烁性能研究

采用中频感应提拉法生长了尺寸为65mm×200mm的Ce:YSO闪烁晶体。通过生长不同掺杂浓度的Ce:YSO晶体,并根据相应的测试结果确定了合适的掺杂比例,进一步研究不同工艺参数对晶体发光均匀性的影响。实验结果表明,当铈离子掺杂浓度为0.16%、二氧化硅补偿浓度为0.10%、结晶分数为60%时,晶体发光强度及发光均匀性最佳,调整工艺参数有利于降低晶体发光不均匀性,但降低效果有限。此外,测试了晶体的脉冲高度谱和脉冲形状谱,Ce:YSO晶体的能量分辨率为7.20%@662keV,衰减时间约为52ns,发光余辉时间为156ns。     

PBSZT大功率压电陶瓷老化性能的研究

为探索Pb1-x-yBaxSry(Sn1/3Nb2/3)0.06(Zn1/3Nb2/3)0.06Ti0.44Zr0.44O3+0.5%MnO2+0.5%Sb2O3(质量分数)大功率铅基压电陶瓷材料的老化机理,进行了A位置换、CeO2掺杂的实验研究.实验结果表明.x(Ba)=5%和x(Sr)=5%的A位复合置换陶瓷得到较好的介电老化性能,一定老化时间内其介电常数变化率为13.9%,添加w(CeO2)=0.7%的掺杂有利于老化性能的提高,一定老化时间内其介电常数变化率为2.2%.对原体系掺杂w(Mn(NO3)22)=0.2%、w(Sb2O32)=0.5%,它们显著地优化其老化性能.     

Er2O3掺杂对BaTiO3陶瓷介电性能的影响

采用溶胶-凝胶法制备了掺杂Er2O3的BaTiO3陶瓷。测试结果表明,掺杂Er2O3能降低BaTiO3陶瓷的电阻率,且在开始时其电阻率随着掺杂量的增大而升高,在掺杂x(Er2O3)=0.003(摩尔分数)时电阻率最高,然后随掺杂量的升高而降低,在掺杂x(Er2O3)=0.007时电阻率最低,从纯BaTiO3陶瓷的2.6 TΩ.m下降为18 GΩ.m,此变化规律有异于La,Ce,Nd,Sm等稀土元素掺杂的规律。掺杂Er2O3使BaTiO3陶瓷的介电性能发生明显变化,掺杂x(Er2O3)为0.001和0.002时,可改善BaTiO3陶瓷的介电性能和频率特性,具有较好的频率稳定性。掺杂Er2O3使BaTiO3陶瓷的居里温度升高为130.9℃,交流电导随着温度的升高而增大,并在居里温度点附近达到最大。     

富钛型钛酸锶钡基陶瓷的微观结构与介电性能

采用传统固相法制备Nd2O3掺杂富钛型(Ba0.75Sr0.25) Ti1+xO3(x为摩尔比)陶瓷,通过扫描电镜及LCR测试系统,研究不同x值、Nd2O3掺杂量及烧结工艺对钛酸锶钡基陶瓷微观结构与介电性能的影响。结果表明,随着x值及Nd2O3掺杂量增大,陶瓷试样均出现柱状第二相。当x=0.01且w(Nd2O3)=0.4%时,陶瓷试样经1 250 ℃烧结2 h后,其室温相对介电常数(εr)高达8.67×103,介电损耗(tan δ)仅为7.87×10-3。随着x值及Nd2O3掺杂量增大,陶瓷的居里峰显著移动。     

ZnS∶Mn纳米晶的制备及磁光性能研究

采用水热法制备了Mn掺杂的ZnS纳米晶,通过X线衍射(XRD)谱、扫描电子显微镜(SEM)、磁性曲线、光致发光谱对其微结构、表面形貌、磁学及光学性能进行了探究。结果表明,ZnS∶Mn纳米晶为球形闪锌矿结构,晶体颗粒大小均匀,平均粒径为20nm。在外加磁场的作用下,ZnS∶Mn纳米晶的磁化强度随着Mn掺杂浓度增加而增加。当掺杂x(Mn)=2%(摩尔分数)时,ZnS∶Mn纳米晶发射光谱的强度最强;当x(Mn)=10%时,离子间相互碰撞引发了浓度猝灭效应及高浓度Mn引入的大量缺陷,使光致发光谱的强度减小。     

2.79μm电光调Q Cr,Er:YSGG激光器北大核心CSCD

采用Cr, Er∶YSGG晶体作为激光增益介质,脉冲氙灯进行泵浦结合电光调Q技术,研制了2.79μm波段固体激光器。Cr, Er∶YSGG晶体中Cr^(3+)掺杂浓度为2 at.%,Er^(3+)离子掺杂浓度为30 at.%。电光晶体选用La_(3)Ga_(5)SIO_(14)(LGS)晶体作为退压调Q工作物质。分析讨论了Cr, Er∶YSGG晶体能级结构以及两种不同Cr^(3+)掺杂浓度对晶体激光性能的影响,谐振腔中输出镜透过率分别为T=70%、T=83%以及T=91%时单脉冲能量及斜效率的变化,并且利用软件模拟分析了晶体内的温度分布以及热透镜焦距随泵浦功率变化情况。结果表明,选用Cr^(3)掺杂浓度为2 at.%的Cr, Er∶YSGG晶体作为工作物质以及透过率为91%的蓝宝石作输出镜时能获得更高的输出能量及更好的光斑模式。当脉冲氙灯注入总能量为259 J,调Q延时设置为180μs,重复频率为5 Hz时,实现了最大单脉冲能量119 mJ的2.79μm激光的稳定输出,在此能量条件下测得脉冲宽度为68.65 ns,平均功率为0.595 W,斜率效率为0.11%。     

SrCO3掺杂对PZN-PZT低温压电陶瓷结构及性能的影响

采用固相法在900℃制备合成了Pb_(1-x)Sr_x(Zn_(1/3)Nb_(2/3))_(0.3 )O_3-(Zr_(0.49)Ti_(0.51))_(0.7)O_3(简写为PZN-PZT+xSrCO_3,x=0%,2%,4%,6%,8%)低温压电陶瓷。采用X射线衍射仪、扫描电子显微镜和准静态压电常数测试仪、铁电测试仪系统地研究了Sr~(2+)取代A位的Pb~(2+)对PZN-PZT陶瓷的相结构、微观结构和电学性能的影响。结果表明,在选定SrCO_3掺杂浓度范围内,PZN-PZT陶瓷呈四方相晶体结构。随着x的增加,晶粒尺寸先增大后减小。掺杂摩尔分数4%的SrCO_3能有效提高PZN-PZT陶瓷的压电性能和铁电性能。当SrCO_3摩尔分数为4%时,PZN-PZT陶瓷有最佳的性能:d_(33)=496 pC/N,k_p=0.58,Q_m=40,T_C=244℃,ε_r=3000,P_r=32.80μC/cm~2,E_c=0.98 kV/mm。     

ZrO2掺杂对Ba(Zn1/3Ta2/3)O3陶瓷介电性能的影响

采用固相反应烧结法制备了ZrO2掺杂的Ba(Zn1/3Ta2/3)O3微波介质陶瓷,研究了陶瓷的烧结特性和介电性能。结果表明,ZrO2掺杂能有效降低Ba(Zn1/3Ta2/3)O3陶瓷的烧结温度,改善陶瓷的微波介电性能。当x(ZrO2)=4%时,Ba(Zn1/3Ta2/3)O3陶瓷致密化烧结温度由纯相时的1 600℃降至1 300℃,同时陶瓷材料的微波介电性能达到最佳值,即介电常数εr=34.79,品质因数与频率的乘积Q×f=148 000(8GHz),谐振频率温度系数τf=0.3×10-6/℃。     

激光波长对镁钌铁铌酸锂的全息存储性能影响

在生长Fe∶LiNbO3熔体中掺进摩尔分数x(Ru2O3) =0.1％和x(MgO)=1％、3％、7％,用提拉法生长镁钌铁铌酸锂(Mg ∶ Ru∶Fe∶LiNbO3)晶体.通过二波耦合光路,分别以红光(632.8 nm)、绿光(532 nm)和蓝光(476 nm)为光源测量晶体的全息存储性能.实验结果表明,在476 nm下,Mg∶Ru∶Fe∶LiNbO3晶体全息存储性能随着Mg离子掺杂浓度的增加而呈现逐渐增强的趋势,与其在红光和绿光下不同.研究了Mg离子掺杂浓度的增加使Mg∶Ru∶Fe∶LiNbO3晶体的蓝光全息存储性能增强的机理.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.