高纯锗晶体的研究进展

高纯锗晶体是制备工艺复杂难度较大的高端光电材料。高纯锗晶体可用于制作高纯锗探测器,在核物理、粒子物理、天体物理、核安全、微量元素分析、安检及国防等领域具有广泛应用。随着国内外核电和暗物质探测实验的快速发展,对高纯锗探测器的需求逐渐扩大,因而高纯锗晶体具有广阔的市场前景。高纯锗晶体的制备研究受到持续关注,欧美国家已经实现高纯锗晶体的商业化生产,国内目前正在开展高纯锗晶体的研制工作,但尚未制备出探测器级高纯锗晶体。高纯锗晶体的制备过程主要包括多晶制备和单晶生长两方面,其中多晶制备是高纯锗晶体制备的关键步骤。简要介绍了高纯锗晶体的发展历史和研究现状,详细论述了高纯锗晶体的制备方法,着重对高纯锗晶体的制备工艺、性能表征、基本特性和应用进展进行总结,最后指出了高纯锗晶体研究中亟待解决的问题和发展趋势。     

生长锗晶体用悬浮石墨坩埚的设计

本文根据传热学与晶体生长条件设计了用于锗晶体生长的石墨坩埚,并成功地用双悬浮石墨坩埚法改进了锗单晶的生长工艺,解决了坩埚在熔体中浮不起来等实际问题。     

锗在红外技术上的应用和发展趋势

本文介绍了锗作为红外光学材料的生产状况及其特性。现在生产的红外用锗单晶φ>200mm、多晶φ>300mm。对锗的光学特性如吸收系数、折射率、透过率等与温度的关系进行了讨论,并展望了国内、外光学锗的应用趋势与发展前景。     

锗纳米线的制备与生长机理

介绍了锗纳米线在制备技术、生长机理方面的研究现状与最新进展，主要对溶剂热合成法、化学气相沉积（CVD）法、模板法和激光烧蚀法等制备方法和金属催化气-液-固（VLS）生长机理、氧化物辅助生长机理等作了较为详尽的论述。     

核辐射探测器用高纯锗(HPGe)晶体的特性

一、引言锗晶体作为半导体材料在电子学领域的应用已在不断下降,但它在核辐射探测器、红外光学及光导纤维等领域的应用却在稳定增长。锗在医药、催化剂等方面的应用也有新发展。由于锗的原子序数大(32)、禁带宽度小(Eg+0.66电子伏)且易干提纯并得到完整的晶体,面对射线又有很高的能量分辨率,     

地球化学样品中微量锗的分析进展

对地质样品中微量和痕量锗的分析方法进行了综述, 介绍了酸溶和碱熔的前处理方法、分离与富集方法以及锗的测定方法, 包括极谱法、石墨炉原子吸收光谱法、原子荧光光谱法、电感耦合等离子体原子发射光谱法和电感耦合等离子体质谱法, 并对锗的分离和分析方法进行了展望。     

<100>P型4英寸无位错锗单晶的研制

从4英寸无位错锗单晶的生长温度梯度条件出发,设计开发了直拉法生长4英寸无位错锗单晶的双加热器热场系统;并对其热场进行了一系列的数值模拟研究,获得了4英寸无位错锗单晶的温度分布、轴向和径向的温度梯度分布以及热应力的分布结果:双加热器热场系统生长的锗单晶中轴向温度梯度在0.1~0.6 K·cm-1范围内,径向温度梯度为0.02~0.26 K·cm-1;锗单晶中局部区域的热应力值超过了锗单晶的临界切应力1 MPa,其他区域的热应力小于临界切应力。实验将双加热器热场系统中生长的无位错锗单晶,按要求切取测试片后进行位错腐蚀测量研究,获得测试片的位错密度和锗晶体的位错纵向分布。论文研究结果表明,锗单晶晶体中的应力分布数值模拟预期结果与实验生长的锗单晶位错腐蚀实验研究结果一致:该双加热器热场系统适合拉制4英寸无位错锗单晶;其位错呈离散分布,位错密度为350~480 cm-2。     

锌掺杂锗酸锶纳米棒及其光催化特性

以乙酸锶、氧化锗及乙酸锶作为原料,通过水热法制备出了锌掺杂锗酸锶纳米棒。通过X-射线衍射、扫描电子显微镜及固体紫外—可见光漫反射光谱分析了锌掺杂锗酸锶纳米棒的结构、形貌及光学特性。X-射线衍射分析表明所得锌掺杂锗酸锶纳米棒由六方Sr Ge O3和三方Zn Ge O3晶相。不同含量锌掺杂的锗酸锶纳米棒的禁带宽度为3.67 e V到2.88 e V。在紫外光照射下,分析了锌掺杂锗酸锶纳米棒光催化降解亚甲基蓝的光催化活性。光催化分析结果显示锌掺杂锗酸锶纳米棒比未掺杂的锗酸锶具有更高的光催化活性。     

痕量锗的分析进展

锗是一种贵重的稀散金属元素,广泛应用于当代高新科技行业。本文综述了近年来分析样品中痕量锗的试样前处理方法及仪器分析进展。介绍了电热板溶解、微波消解和密闭罐消解前处理样品对测定痕量锗的影响。总结了近年来痕量锗的仪器分析方法包括电感耦合等离子体发射光谱法、原子吸收光谱法、原子荧光光谱法、电感耦合等离子体质谱法、光度法、电化学法和离子色谱法等。指出了不同方法的特点及使用范围,并展望了痕量锗的前处理及其分析方法的发展方向。     

国内分析测定微量锗的研究

介绍了近几年微量锗分析测定方法的研究进展，对用于微量锗分析测定的吸光光度法、原子吸收光谱法、极谱法等分析方法进行了评述，并对今后微量锗分析测定方法进行了展望。     

Crystal Growth and Characterization of Ca3NbGa3Si2O14 Single Crystal

Single crystals of Ca3NbGa3Si2O14 (CNGS) with ordered Ca3Ga2Ge4O14 (CGG) structure were successfully grown from stoichiometric melts by conventional Czochralski technique along the a-axis and two large (001) facets and two small (100) facets appear in every crystal. An arrangement of parallel steps and a clear height change were observed in (001) facet by atomic force microscopy (AFM). High-resolution X-ray diffraction (HRXRD) results indicate that CNGS crystals have good quality and free low-angle boundaries. The crystals also exhibit good optical quality and high optical transmittance in c-direction.     

ICP-AES Determination of Germanium in GdSiGe Series Alloys as Magnetic Refrigeration Material

The ICP-AES method for the determination of Ge in GdSiGe series alloys was studied.As the three main elements in the alloys,Gd,Si,and Ge differ greatly from each other in chemical properties,it was difficult to pretreat the sample.Two decomposition methods were compared,and a mixture of HNO3＋HF was used to decompose the sample and the effect of the HF amount on the sample decomposition was examined.The adsorption effect of GdF3 on Ge was discussed.Three GdSiGe series alloy samples were analyzed,and the RSDs of this method were in the range of 0.85%～2.66%.     

碱熔-强酸型阳离子交换树脂分离-电感耦合等离子体质谱法测定地质样品中硼锗钼锡碘钨

B、Ge、Mo、Sn、I和W是区域地质调查样品54种元素必测项目,目前对这6种元素的测定广泛使用的方法基本是单独或两项结合进行样品的制备和测定,分析效率较低。实验建立了Na₂O₂熔融样品,强酸型阳离子树脂交换分离高含量钠盐,电感耦合等离子体质谱法(ICP-MS)同时测定地质样品中B、Ge、Mo、Sn、I和W的方法。通过试验确定了对于0.5000g地质样品,以3.0g Na₂O₂为熔剂于750℃熔融8min,样品可熔解完全;对于引入的钠盐,通过对待测溶液使用强酸型阳离子交换树脂动态交换振荡30min可消除Na⁺对待测元素的影响;且测试时在每2个待测液之间以0.5%(V/V)氨水作清洗液可降低B、I的记忆效应。采用校正方程在线校正了⁷⁴Ge的同量异位素干扰;选用碰撞模式测定Mo和W,消除多原子离子干扰;B、Ge、Sn和I选用普通模式测定。结果表明,在优化的条件下,B、Ge、Mo、Sn、I和W的检出限在0.092~0.57μg/g之间。按照实验方法对土壤成分分析标准物质GBW07451和水系沉积物成分分析标准物质GBW07362中B、Ge、Mo、Sn、I和W进行测定,相对误差和相对标准偏差均满足DZ/T 0258—2014《多目标区域地球化学调查规范》的要求。优化后的方法用于实际地质样品的分析,测定值与经典方法的结果一致,实现了B、Ge、Mo、Sn、I和W的同时测定,提高了测试效率。     

密闭消解-电感耦合等离子体质谱法测定铅矿石中痕量镓铟铊镉锗

铅矿床具有较高品位的各种稀散元素,因此准确测定铅矿石中Ga、In、Tl、Cd、Ge,对于矿产资源的节约、开发利用等具有重要意义。采用密闭消解方式处理样品,同时在消解过程中加入H₂SO₄(1+4)并水浴加热以沉淀分离Pb基体,分别选择⁶⁹Ga、¹¹⁵In、²⁰⁵Tl、¹¹⁴Cd、⁷²Ge作为分析同位素,¹⁰³Rh为内标校正Ga、In、Cd、Ge,¹⁸⁷Re为内标校正Tl,实现了电感耦合等离子体质谱法对铅矿石中痕量稀散元素Ga、In、Tl、Cd、Ge的测定。实验表明,采用标准(STD)模式测定,Ga、Tl、Cd的背景等效浓度比动能歧视(KED)模式高出一个数量级,而In、Ge的背景等效浓度和KED接近,因此确定采用KED模式测定Ga、Tl、Cd,采用STD模式测定In、Ge;对KED模式下He气流速进行了优化,确定He气流速为5.8mL/min。方法线性方程的相关系数均不小于0.9992,Ga、In、Tl、Cd、Ge的方法检出限分别为0.0520、0.0392、0.0196、0.0212、0.0437μg/g。采用实验方法测定铅矿石实际样品中Ga、In、Tl、Cd、Ge,测得结果的相对标准偏差(RSD,n=6)为1.3%~5.0%,加标回收率为86%~112%。将实验方法应用于铅矿石标准物质中这5个元素的测定,所得结果与认定值吻合。     

The trapping of positrons by dislocations produced in single crystal bending

The deformation by bending of high purity copper and zinc single crystals was studied by detection and measurement of the Doppler-broadened gamma ray spectrum due to the annihilation of positrons in the crystals. The measurements were performed with a Ge(Li) spectrometer. The crystals were oriented and bent so as to introduce primarily edge dislocations into the material. The range of dislocation densities studied was from about 1.6 × 10⁹ m^-2 to 1.3 × 10¹² m^-2. Upon bending the copper crystals showed essentially a linear increase in shape factor (a parameter which describes the positron trapping) above a calculated dislocation density of 5 × 10¹¹ m⁻². The positron trapping rate per unit dislocation density was calculated from the experimental data and certain assumptions in the trapping model and found to bebetween 1.6 × 10¹⁶ and 3.5 × 10¹⁶ s⁻¹ Annealing of the bent crystals is also discussed from the standpoint of the effect it has on the trapping of positrons. Polygonization produced an increase in shape factor which is attributed to trapping by low angle subgrain boundaries.     

Gd2O3-HfO2栅介质薄膜的外延制备及Ge-MOS电学特性分析

以Gd2O3-HfO2( GDH)固溶氧化物作为靶材,采用脉冲激光沉积技术(PLD)在Ge(100)衬底上制备了GDH高k栅介质外延薄膜,其外延生长方式为“cube-on-cube”,GDH薄膜与Ge(100)衬底的取向关系为(100)GDH∥(100)Ge和[110] GDH∥[110]Ge.通过反射式高能电子衍射(RHEED)技术研究了激光烧蚀能量和薄膜沉积温度对薄膜晶体结构的影响,分析了二者与薄膜的取向关系,激光烧蚀能量对薄膜取向影响更为显著.得到较优的GDH外延薄膜沉积工艺为:激光烧蚀能量为3 J·cm-2、薄膜的沉积温度为600℃.用磁控溅射制备了Au/Ti顶电极和Al背电极,其中圆形的Au/Ti电极通过掩膜方法获得,直径为50μm.采用Keithley 4200半导体测试仪对所制备Au/Ti/GDH/Ge/Al 堆栈结构的Ge-MOS原型电容器进行电学特性分析,测试条件为:I-E测试的电场强度0～6MV·cm-1,C-V测试的频率300 kHz～1 MHz,结果表明,厚度为5nm的GDH薄膜具备良好介电性能:k-28,EOT ～0.49 nm,适于22 nm及以下技术节点集成电路的应用.     

改性花生壳吸附分离湿法炼锌溶液中的镓和锗

研究酒石酸改性花生壳对湿法炼锌浸出液中镓和锗的吸附过程,考察吸附时间、改性花生壳的用量、溶液初始pH值、吸附温度以及溶液中镓、锗初始浓度对镓、锗吸附率的影响,并探讨了花生壳吸附镓、锗动力学.结果表明:改性花生壳可实现湿法炼锌浸出液中镓和锗的有效分离,且对锗的吸附效果优于镓,在吸附时间为3 h、溶液初始pH=3、吸附温度...     

Synthesis and photoluminescence properties of octahedral K_2(Ge,Si)F_6:Mn~(4+) red phosphor for white LED

A novel red-emitting K_2(Ge,Si)F_6:Mn~(4+) phosphor with uniform morphology was synthesized by co-precipitation method. The pure K_2GeF_6 phase with P63 mc space group other than P3m1 space group was affirmed just by incorporation of Si in K_2GeF_6 at room temperature according to XRD characterization. SEM images showed lamellar and octahedron grain morphology for K_2GeF_6:Mn~(4+) and K_2(Ge,Si)F_6:Mn~(4+) phosphors, respectively. It was also found that the photoluminescence excitation(PLE) and photoluminescence(PL) showed slight displacement in K_2GeF_6:Mn~(4+) and K_2(Ge,Si)F_6:Mn~(4+) system. And the zero-phonon line(ZPL) of the PL spectrum of K_2GeF_6:Mn~(4+) with Si showed a strong peak. Meanwhile crystalline field surrounding Mn~(4+) changes could affect the decay time in this fluoride system. The color gamut of the LED devices based on K_2(Ge,Si)F_6:Mn~(4+) and K_2GeF_6:Mn~(4+) reached up to 94.58% NTSC(National Television Standards Committee) and 94.386% NTSC, respectively, that was much higher than that based on nitride red phosphors. All these original characteristics in K_2(Ge,Si)F_6:Mn~(4+) phosphor are desirable for potential applications as a red phosphor for improving lighting and display quality of conventional white LEDs.     

Investigation of SiGe-on-Insulator Novel Structure

SiGe-on-Insulator (SGOI) is an ideal substrate material for realizing strained-silicon structures that are very competing and popular in present silicon technology. In this paper, two methods are proposed to fabricate SGOI novel structure. One is modified Separation by Implantation of Oxygen (SIMOX) starting from pseuodomorphic SiGe thin film without graded SiGe buffer layer. Results show that two-step annealing can improve the cystallinity quality of SiGe and block the Ge diffusion in high temperature annealing. SGOI structure with good quality has been obtained through two-step annealing. The second method is proposed to achieve SGOI with high content of Ge. High quality strained relax SiGe is grown on a compliant silicon-on-insulator (SOI) substrate by UHCVD firstly. During high temperature oxidation,Ge atoms diffuse into the top Si layer of SOI. We successfully obtain SGOI with the Ge content of 38%, which is available for the growth of strained Si.     

Epitaxial growth and characterization of Gd2O3-doped HfO2 film on Ge （001） substrates with zero interface layer

The GHO （Gd2O3-doped HfO2） films were epitaxially grown on Ge （001） substrates adopting cube-on-cube mode with zero interface layer using pulsed laser deposition （PLD）. Reflection high-energy electron diffraction （RHEED） and high-resolution transmission electron microscopy （HRTEM） observation revealed a sharp interface of GHO/Ge and orientation relationship corre-sponding to （001）GHO//（001）Ge and [011] GHO//[011]Ge. The band offset for GHO/Ge stack was evaluated to be 3.92 eV for va-lence band and 1.38 eV for conduction band by X-ray photoelectron spectrum. Small equivalent oxide thickness （0.49 nm） and inter-face state density （7×1011 cm-2） were achieved from Au/Ti/GHO/Ge/Al capacitors.