现代ZnO体单晶生长

ZnO单晶可用气相输运、水热溶液生长和高压熔体生长三种技术生长。己用水热生长技术生长出三英寸单晶。本文重点介绍大尺寸ZnO单晶的水热生长工艺,并与气相及熔体生长单晶进行了比较。     

ZnSe单晶的气相生长及光学性质

用改进的化学气相输运技术(CVT),以Zn(NH4)3Cl5为新的气相输运剂,直接从单质Zn和Se一步在封密管中生长了ZnSe单晶,升华温度1001～1020℃,管内温差<4℃。经过两周生长,得到8mm×7mm×0.8mm的绿色ZnSe晶体。XRD表明晶体表面为(111)面;受气固界面形貌影响,双晶衍射半高峰宽为50s;PL谱由DPA和SA两个发光峰组成;并研究了晶体片的吸收光谱、荧光光谱、反射光谱和红外透过等光学性质。     

在GaAs(100)衬底上离化团束外延ZnSe单晶薄膜

ZnSe是一种理想的蓝紫色发光材料，用于制作发光器件有较大的应用前景，采用单源喷发、离化原子团束（ICB）技术在GaAs（100）上外延ZnSe单晶薄膜，并用电子能谱分析了外延薄膜的成分。用X射线衍射和RHEED研究了外延ZnSe单晶薄膜结构和外延质量。研究了淀积能量和衬底温度对薄膜质量的影响。得到了摆动曲线半高宽为133rad·s，并具有原子水平平整程度的ZnSe（100）单晶薄膜。外延薄膜存在0．2～0．4μm的应变过渡层，过渡层随淀积能量的增大而变薄。     

ZnSe多晶料的合成方法及其工艺研究

简述了单晶生长用ZnSe多晶料的制备方法.分别以颗粒状和粉末状的高纯单质Zn和Se为原料,采用元素直接合成法合成了ZnSe多晶料,分析了直接合成的困难所在.理论分析和实验研究均表明:前期H2-O2焰下高温灼烧(～1500℃)使Zn和Se充分反应,是合成工艺的关键;延长后期恒温时间(不少于2周),使扩散反应进行完全,有利于获得更接近化学计量比的ZnSe多晶料.     

Cu掺杂ZnSe高效量子点的合成及其光学特性研究

采用生长掺杂方式制备了Cu掺杂ZnSe高效量子点, 探索了不同Zn、Se前驱体配比对ZnSe晶核以及ZnSe:Cu量子点质量的影响, 并研究了Cu离子掺杂过程中的光谱特征。研究表明, 进一步通过在表面掺杂的ZnSe:Cu量子点上同质包覆ZnSe壳层, 能够实现其发光效率和稳定性的有效提高; 采用配体交换能够实现ZnSe:Cu量子点由油溶性到水溶性的转变。这种新型的掺杂量子点有望替代传统含Cd量子点应用于环境友好型固体发光器件和生物标记。     

大尺寸ZnTe单晶生长技术的研究进展

介绍了以光电应用为背景的大尺寸ZnTe单晶生长技术的研究进展,综述了大尺寸ZnTe单晶不同生长技术的特点及其对单晶性能的影响,重点分析了为解决ZnTe生长过程中存在的蒸汽压过高的问题,通过控制提高Te的比例,实现低温低压生长,对比了不同生长方法的生长机理差异及其对单晶尺寸、缺陷和性能的影响,为寻求解决大尺寸单晶生长面临的问题提供了参考。     

YBa2 Cu3 O7-x单晶的制备

介绍了制备高温超导体YBa2Cu3O7-x单晶的主要方法,分析了在制备过程中存在的问题,指出液相的性质是影响生长速率的重要因素.在此基础上,着重探讨了通过控制氧压和元素替代等方法来改变液相的性质,从而达到提高YBCO单晶生长速率的目的.     

Hg1—xCdxTel生长中的溶质再分配及其对生长条件的限制

本文以ＨｇＴｅ－ＣｄＴｅ伪二元相图为基础，分析了Ｈｇ１－ｘＣｄｘＴｅ单晶生长过程中分凝特性及扩散规律。从维持平面生长界面的角度出发，确定了不同温度梯度下生长速度选择的上限，并从获得成分均匀晶体的角度出发讨论了晶体生长速度下限的选择条件。     

异质外延MgO/SrTiO3薄膜中界面应力研究

本文利用激光分子束外延(LMBE)技术在SrTiO3(100)单晶基片上外延生长MgO薄膜，同时又在MgO(100)单晶基片上外延生长SiO3(STO)薄膜。通过反射高能电子衍射(RHEED)仪原位实时监测薄膜生长，研究薄膜的生长过程。并结合X射线衍射(XRD)仪来分析在不同的生长条件下，不同应力对薄膜外延生长的影响。在压应力情况下，MgO薄膜在STO基片上以单个晶胞叠层的方式生长，即以“Cubicon Cubic”方式进行外延；在张应力情况下，由于膜内位错较多，STO薄膜在MgO基片上以晶胞镶嵌的方式进行生长，即以“Mosaic”结构进行外延；提高生长温度，可以减少膜内位错，提高外延质量，使STO薄膜在MgO基片上以较好的层状方式外延生长。     

垂直梯度凝固法生长半绝缘GaAs单晶的工艺研究

在国产三温区VGF单晶炉上，研究了非掺GaAs半绝缘单晶的液封垂直梯度凝固法生长技术。讨论了引晶、坩埚设计与质量、PBN坩埚的剥落、B2O3的水份控制等因素对单晶生长的影响，基本解决了VGF的工艺问题。通过多炉生长，得到了Φ2″=VGF非掺半绝缘低位错全单晶。     

纳米Zn1-xFexSe薄膜的制备和结构研究

采用双源热蒸发方法制备了纳米 Zn1-xFexSe稀释磁性半导体薄膜,根据 X 射线衍射谱和Raman散射谱研究了薄膜的晶体结构和声子谱特征。结果表明:Zn1-xFexSe薄膜中纳米晶粒的晶格常数随Fe含量增加而增大;通过 Raman 散射光谱观察到明显的声子限域效应,与 ZnSe体材料相比,Zn1-xFexSe薄膜同光学声子模对应的 Raman 散射峰表现出宽化和红移;纳米晶粒的晶格膨胀导致 Raman散射峰红移随Fe含量增多而相应加大。     

ZnO nanorods on in-situ synthesized ZnSe grains

The ZnO nanorods grown on in-situ synthesized ZnSe grains through the chemical vapour deposition method are reported here for the first time. With a suitable growth condition, single crystal ZnO nanorods grow on the well-defined bounded facets of the random shape ZnSe grains using Zn and Se powders without any metal catalyst. The growth direction of ZnSe nanorods on a facet of a ZnSe grain is quite uniform. The synthesis mechanism of the ZnO nanorods on the ZnSe grains is proposed. The effects of the Se powder usage on the ZnO-ZnSe products and the photoluminescence of the products are investigated.     

移动加热器法晶体生长的研究

介绍了移动加热器法晶体生长的基本原理及其优缺点,报道了国内外最新研究进展,讨论了不同工艺参数,如磁场、加速坩埚旋转、重力、生长速度、温度等对THM生长晶体的影响,提出了提高THM生长晶体速度的设想,并就未来THM生长晶体的研究方法和发展趋势提出了自己的看法。     

The fabrication of light-emitting devices from hot-pressed ZnSe powders

A hot-pressing process was developed to synthesize fine ZnSe powders into compacts with high bulk density. The hot-pressed ZnSe powder compacts after an annealing treatment in the Zn-Al alloy melt were readily processed into light-emitting devices based on a metal-semiconductor (M-S) device structure. The fabricated devices are found to emit light in the orange region of the visible spectrum and have a room temperature quantum efficiency of the order of 10^–6 photons/electron in the reverse direction. The photoluminescence and electroluminescence characteristics of the hot-pressed ZnSe powder compacts are also found to be very similar to those observed in single crystal material.     

Optimization of the structural, microstructural and optical properties of nanostructured Cr:ZnSe films deposited by magnetron co-sputtering for mid-infrared applications

In order to obtain optimally adherent films having the highest mid-infrared photoluminescence efficiency, nanostructured Cr²⁺:ZnSe films were deposited at room temperature on various substrates by magnetron radiofrequency co-sputtering of a SiO₂ target covered by a given number of ZnSe and Cr chips, at different Argon pressures and radiofrequency powers. The deposition parameter effect on the compositional, structural, microstructural and optical properties of the films has been investigated using X-ray reflectivity and diffraction, optical transmission spectroscopy, transmission electron microscopy, and photoluminescence studies. The corresponding films are composed by highly textured cubic and hexagonal ZnSe phases and exhibit strong tensile in-plane residual stresses. The evolution of the tensile residual stress and porosity values are consistent with the optical properties of the layers, and in particular the evolutions of both optical gap and refractive index. The room temperature mid-infrared (2-3 μm) photoluminescence measurements under direct excitation (1850 nm) revealed that chromium has been incorporated in the Cr²⁺ active state, and the corresponding fluorescence efficiency for an optimized thin film is only two times smaller than the one of a Cr²⁺:ZnSe reference bulk single crystal.     

碘化铅单晶生长及探测器的研究进展

PbI2单晶体是性能优异的室温半导体核辐射探测器新材料。主要介绍了PbI2晶体生长技术及其室温核辐射探测器研究发展的最新动态,综述了PbI2晶体的3种主要生长方法(气相法、熔体法和凝胶法)的原理和优缺点,重点阐述了熔体法生长PbI2晶体的影响因素及研究进展,提出了PbI2单晶制备技术存在的主要问题和今后的发展方向。     

Source-material dependent growth limitations in unseeded dissociative sublimation of ZnSe

It has been found that besides temperature conditions, source-material composition (phase purity, impurity concentration and non-stoichiometry) dominates the quality of ZnSe crystals due to mass transport limitations and fluctuations. Therefore, without definite pretreatment, commercially supplied ZnSe source material is unsuitable for the physical vapour growth of ZnSe in closed systems. In this work the results of various characterization methods have been closely related to the optimal source preparation. For characterization of the non-stoichiometry of crystals, a qualitative relation between colour and zinc vacancy concentration has been established.     

异型纳米AlOOH在水热条件下的界面模型及生长机制

根据古典和现代结晶理论,结合AlOOH晶体结构特点,构建了晶体生长界面模型,预测了晶体生长速率,揭示了异型纳米AlOOH在水热过程中的生长机制.采用高分辩透射电镜、X射线等检测手段,分析了不同水热条件下的实验样品.结果表明;AlOOH在（010）、（001）面上显露的氧基和羟基多于（100）、（101）面,酸性环境促进...     

单晶体材料内应力研究进展

随着科学技术的发展,晶体的力学性质,如弹性、脆性、硬度和解理性等引起了人们的重视。晶体材料应力分布取决于很多复杂因素(加热、退火、提拉、切割、搬运以及生长过程中的各种力学因素)。从应力表征、硬度及断裂韧性的测试方法入手,回顾并总结了晶体材料力学参数的表征手段,阐述了晶体开裂的分布规律及原因。其中光测方法(主要包括光弹法、X射线衍射法等)因其对晶体材料无任何机械损伤、检验灵敏度高而应用广泛:光弹性是光学晶体材料的重要特性,利用光弹仪测定光程差,根据平面光弹性的应力-光学定律确定主应力差;X射线衍射方法测定样品中宏观应力具有无污染、测量精度高等特点。压痕实验和划痕实验是表征晶体硬度的主要手段,结合化学腐蚀和光学观测方法可以有效探讨晶体开裂的微观机理。     

Optimum growth of ZnSe film by molecular beam deposition

Zinc selenide (ZnSe) thin film has been grown originally on Coning 7059 glass substrate by molecular beam deposition (MBD). Optimum growth condition has been determined rapidly by comparing and analyzing the relative characteristics of X-ray diffraction spectrum. In this paper, films deposited at different substrate temperatures as a function of Zn/Se beam equivalent pressure (BEP) ratios are investigated. As-grown ZnSe films are polycrystalline and have a cubic (zinc-blende type) structure by the X-ray diffraction technique. The composition of ZnSe film was determined by Energy dispersive spectroscopic (EDS) analysis. Optical properties of ZnSe film were characterized by photoluminescence spectra. Structural parameters such as lattice constant, grain size, strain, dislocation density calculated are correlated with various growth conditions. The dependence of film properties on various substrate temperatures and Se/Zn BEP ratios has been discussed in detail. Finally, high quality of ZnSe film has been successfully obtained and ready for device application.