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分析高组份合金时,用传统的内标法误差太大,加上诱导含量计算法亦无明显改善。本文首先对超合金分别进行了内标-诱导含量法与定时曝光法实验,肯定了定时曝光法。通过算术平均误差的比较、相关系数的比较、置信区域比较等判据,论证了内标法和定时法的精度。再用真空光量计定时曝光法成功地分析了HK-40合金,并作出了其工作曲线。 相似文献
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基于共振干涉法、相位法和反射回波法测量了空气和水中超声波的传播速度,比较了三种方法的优缺点,共振干涉法和相位法可测量气体和液体中的声速,反射回波法可测量液体和固体中的声速;相位法误差最小,共振干涉法误差相对较大。共振干涉法研究了示波器接收的交变电压随传播距离的变化规律,计算得空气和水中超声波的损耗系数分别为0.01381、0.01829,超声波在水中的损耗较大。使用Origin软件直线拟合,对实验结果进行分析和评价。 相似文献
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Man-made synthetic structures involving epitaxially grown thin films of one or more compound semiconductors have been finding an increasingly important role in semiconductor device technology.1 Remarkable advances have been made over the past decade in the realization of a variety of such structures involving III-V, II-VI. and IV-VI compound semiconductors, as well as combinations of semiconductors with dielectrics and metals.' The major part of this progress has come about primarily due to the advent of, and refinements in, two vapor phase growth techniques — molecular beam epitaxy (MBE)' and metal-organic chemical vapor deposition (MO-CVD).3 The underlying motivation has been the remarkably altered and potentially useful electronic and optical properties of electrons, holes, and light arising from their confinement in a quasi-two-dimensional environment in the ultrathin films (thickness less than the particle deBroglie wavelength).4 However, confinement of the par- ticles in such ultrathin layers (typically 10 to 200 Å) places stringent requirements on the atomic level structural and chemical perfection of the films and their interfaces involved. At the same time, spatial control of the abruptness (in the growth direction) and uniformity (in the planes normal to the growth direction) of dopant distribution becomes equally sig- nificant in realizing the potential electrical and optical properties of camers and light in such structures. Both MBE and MO-CVD have been shown to meet these stringent requirements for the growth of III-V compound semiconductors, although differences between materials and structures produced by these techniques also remain. The purpose of this article is to review the progress made in understanding the process of MBE growth with particular focus on computer simulations of the growth proess.1–15 These simulations have provided con- siderable insight into the role played by the atomistic surface kinetic processes in controlling the morphology of the growing surfaces and consequently the resulting nature of the interfaces formed upon deposition of another material on such surfaces. 相似文献
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为了使研究者能更详细地了解类金刚石(DLC)薄膜的研究现状,综述了类金刚石薄膜的特性及应用,分析对比了目前常用的一些类金刚石薄膜的制备方法,包括物理气相沉积法(PVD)和化学气相沉积法(CVD),并对类金刚石薄膜的抗强激光损伤特性以及提高其激光损伤阈值的方法进行了论述。结果发现,利用PVD法制备的DLC膜的硬度可以达到40 GPa~80 GPa,且薄膜的残余应力可以达到0.9 GPa~2.2 GPa之间,而CVD法则由于反应气体的充入导致类DLC薄膜的沉积速率大大降低,故使用率不高。同时,优化膜系的电场强度设计,采用合理的制备工艺,进行激光辐照后处理,施加外界电场干预均可有效地提高DLC薄膜的抗激光损伤能力, 且目前的DLC薄膜的激光损伤阈值可达到2.4 J/cm2。 相似文献
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一维量子材料制备新进展 总被引:5,自引:0,他引:5
文章简要评述了一种制备一维半导体量子材料的新方法,即用碳纳米管作为模板,通过化学气相反应生长半导体纳米线,用此方法已经成功地制备出了一系列碳化物纳米线,更重要的是还制备出了GaN纳米线. 相似文献
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倪哲明 《光谱学与光谱分析》1995,(6)
不同形态的元素其生物效应差别很大,决定它们在环境中的行为和归宿。金属有机化合物分析属金属形态分析。这类化合物的分离多用色谱法。但色谱所用的检测器如电子捕获检测器、火焰离子化检测器和紫外可见光度计对金属的选择性较差,而原子光谱由于对金属有较好的选择性,用作色谱的检测器可以避免在测定过程中的许多干扰。本报告简要介绍色谱和原子光谱的各种联用方法及其在环境分析中的应用。 相似文献
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GaN薄膜材料广泛应用于发光二极管(LED),激光二极管(LD)等光电器件。但是GaN基器件的制备与应用以及器件推广很大一部分取决于其器件的价格,常用的方式是在单晶蓝宝石衬底上沉积制备GaN薄膜样品,单晶蓝宝石衬底晶向择优,可以制备出高质量的GaN薄膜样品,但是单晶蓝宝石衬底价格昂贵,一定程度上限制了其GaN基器件推广使用。如何在廉价衬底上直接沉积高质量的GaN薄膜,满足器件的要求成为研究热点。石英玻璃价格廉价,但是属于非晶体,没有择优晶向取向,很难制备出高质量薄膜样品。本研究采用等离子体增强金属有机物化学气相沉积系统在非晶普通石英衬底上改变氮气反应源流量低温制备GaN薄膜材料。制备之后采用反射高能电子衍射谱、X射线衍射光谱、室温透射光谱和光致光谱对制备的薄膜进行系统的测试分析。其结果表明:在氮气流量适当的沉积参数条件下,所制备的薄膜具有高C轴的择优取向,良好的结晶质量以及优异的光学性能。 相似文献
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REBa2Cu3O7-x (RE:钇、钆等稀土元素,REBCO)高温超导体因其具备较高的不可逆场和上临界场等优越性能,一经发现就备受关注。但由于材料本身固有的陶瓷性及弱连接等属性,导致其实际应用起来难度较大。目前,人们已经发展了诸多制备工艺来克服这些困难,实现了REBCO超导体的实际应用。按照前驱膜沉积方法可将REBCO超导薄膜的制备分为物理法和化学法。本文综述了物理气相沉积(PVD-Physical Vapor Deposition)法中多源共蒸发法制备REBCO超导薄膜的技术起源及演变历程,并与金属有机沉积、金属有机化学气相沉积、脉冲激光沉积等不同方法生产的REBCO超导带材进行对比,突出多源共蒸发法制备的REBCO薄膜性能优异、在商业化生产效率上具有更大的优势。最后对多源共蒸发法制备REBCO超导薄膜进行总结及展望,解决多源共蒸发沉积制备REBCO薄膜的成相机理、提高薄膜的钉扎中心等问题对未来第二代高温超导带材的大规模应用具有重要意义。 相似文献
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随着未来信息器件朝着更小尺寸、更低功耗和更高性能方向的发展,构建器件的材料尺寸将进一步缩小.传统的"自上而下"技术在信息器件发展到纳米量级时遇到瓶颈,而气相沉积技术由于其能在原子尺度构筑纳米结构引起极大关注,被认为是最有潜力突破现有制造极限进而在原子尺度构造、搭建物质形态的"自下而上"方法.本文重点讨论适用于低维材料的原子尺度制造的分子束外延技术和原子层沉积/刻蚀技术.简要介绍相关技术中蕴含的科学原理及其在纳米信息器件加工和制造领域的应用,并探讨如何在原子尺度实现对低维功能材料厚度和微观形貌的精密控制. 相似文献
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Ming L. YuLisa A. DeLouise 《Surface Science Reports》1994,19(7-8):285-380
This Report reviews the use of molecular-beam reactive scattering to study the surface reactions of gas molecules on semiconductors which have relevance to microelectronic technologies. Modern semiconductor fabrication techniques rely heavily on dry processes where gas-surface reactions are the basic premise. This article focuses on the use of supersonic molecular-beam-surface scattering to study the dynamics and kinetics of surface reactions connected with the growth and etching processes on semiconductor surfaces. The discussion on growth processes covers the oxidation of silicon and germanium, the tungsten-hexafluoride-based tungsten deposition, and the organometallic chemical vapor deposition of gallium arsenide. The discussion on etching processes covers the halogen-based etching of gallium arsenide and silicon. An overview of the experimental technique and the underlying principles in surface-reaction dynamics and kinetics is included for readers in the technology area. The potential use of the molecular beams for actual semiconductor materials processing is also discussed. 相似文献
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C. Garrido-Suarez D. Braichotte H. van den Bergh 《Applied Physics A: Materials Science & Processing》1988,46(4):285-290
Microscopic ohmic contacts are made by laser chemical vapor deposition of platinum on a Pyrex substrate. The electrical conductivity of the deposited metal stripes is measured as a function of the laser power, the writing speed, and the organometallic vapor pressure. The latter appears to be the key parameter for producing contacts with low resistance at high writing speeds. Even on these transparent substrates there is no apparent advantage in using light at 350 nm, where photolysis may in principle play a significant role, over using visible light where photolysis is not effective. 相似文献