共查询到18条相似文献,搜索用时 140 毫秒
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本文采用磁控溅射法, 衬底温度500 ℃下在硅衬底上分别制备具有Ge填埋层的a-Si/Ge 薄膜和a-Si薄膜, 并进行后续退火, 采用Raman光谱、X射线衍射、原子力显微镜及场发射扫描电镜等对所制薄膜样品进行结构表征. 结果表明, Ge有诱导非晶硅晶化的作用, 并得出以下重要结论: 衬底温度为500 ℃时生长的a-Si/Ge薄膜, 经600 ℃退火5 h Ge诱导非晶硅薄膜的晶化率为44%, 在相同的退火时间下退火温度提高到700 ℃, 晶化率达54%. 相同条件下, 无Ge填埋层的a-Si薄膜经800 ℃退火5 h薄膜实现晶化, 晶化率为46%. 通过Ge填埋层诱导晶化可使在相同的条件下生长的非晶硅晶薄膜的晶化温度降低约200 ℃. Ge诱导晶化多晶Si薄膜在Si(200)方向具有高度择优取向, 且在此方向对应的晶粒尺寸约为76 nm. 通过Ge诱导晶化制备多晶Si薄膜有望成为制备高质量多晶Si薄膜的一条有效途径. 相似文献
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利用透射电子显微镜(TEM)对有化合物生成(Pd2Ge和PdGe等)的Pd,Ge薄膜体系中的分形晶化行为进行了系统研究实验结果和分析表明:在各种退火温度条件下,Pd-Ge共蒸膜都难以发生分形晶化,Pd/a-Ge双层膜较a-Ge/Pd双层膜更容易导致分形结构的产生Z化合物Pd2Ge和PdGe的形成对薄膜中的分形晶化有明显的抑制作用,体系中能否出现分形结构,取决于非晶Ge的成核生长和Pd,Ge化学反应两种过程的相互竟争.
关键词: 相似文献
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本文报道利用单辊方法制备的非晶Nd3Fe81B16合金的晶化及其对磁性和M?ssbauer谱的影响。发现在非晶Fe81B19合金中用3at%Nd取代B,使非晶Fe81B19合金的晶化温度提高88℃。在适当的退火条件下晶化后样品在室温下的磁性是:σs=189emu/g,σr/σs=0.7,iHc=2.15kOe,Br≈12kG,bHc=2kOe,(BH)max≈8MGOe。与目前广泛使用的六角铁氧体相比,bHc相近,但Br和(BH)max远比六角铁氧体高。这种材料仅含有少量的Nd,因此可能开发为一种新的廉价永磁材料。本文对少量Nd的添加对非晶FeB合金的晶化温度,磁性和M?ssbauer谱的影响进行了讨论。初步探讨了高矫顽力的来源,认为它的磁化和反磁化过程可以用畴壁钉扎理论解释。
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采用分子动力学模拟研究了非晶Ag的等温晶化过程,通过原子轨迹逆向追踪法分析了不同类型晶体团簇的结构遗传与组态演化.在团簇类型指数法的基础上,根据基本团簇种类与联结方式不同,提出了一种可区分fcc单晶、多晶与混晶团簇的分析方法.在非晶Ag等温晶化过程中,基于团簇结构的连续遗传性特征,发展了一种可区分fcc单晶、多晶与混晶晶胚与晶核的结构分析技术.结果发现:不论临界尺寸还是几何构型,不同类型的晶核结构都存在差异,其中fcc单晶临界尺寸最小,多晶次之,混晶最大; fcc单晶与多晶壳层原子中有少量hcp和bcc原子,而混晶壳层则全部为非晶类原子,并且fcc单晶、多晶与混晶的临界晶核都不是球型结构. 相似文献
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应用小角X射线散射技术研究了Cu60Zr30Ti10非晶合金从300到813 K之间微结构的演化情况.发现在淬火状态下Cu60Zr30Ti10非晶合金中存在直径30 nm左右的富Cu区.非晶的结构弛豫包括573 K之前的低温结构弛豫和573 K到玻璃转变温度的高温结构弛豫,弛豫的结果是产生含有有序原子团簇的富Cu区,这些有序原子团簇的富Cu区是随后晶化过程中晶核产生的基础.Porod曲线分析表明,晶化生成的纳米体心立方CuZr相和基体之间有明锐的界面.
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小角X射线散射
非晶合金
结构弛豫
晶化 相似文献
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本文用透射电子显微镜观察了a-Ge/Au双层膜在不同退火温度后出现的分形区域,并计算了它们的分数维数。100℃退火时,触发分形结晶区的成核位较少,形成良好的具有无规分叉、自相似的分形区,分数维数为1.785±0.01。200℃退火时,成核位迅速增加,除了分数维数为:1.818±0.008的分形区外,还出现孤立的无枝叉结构的岛状区域。300℃退火时,只出现尺寸很不相同的两种岛状区域,对上述枝叉伏、岛状区域的出现以及a-Ge膜的晶化和Au膜缩聚之间的关系进行了讨论。
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Nobutoshi Arai Hiroshi Tsuji Masayuki Ohsaki Toyotsugu Ishibashi Junzo Ishikawa 《Applied Surface Science》2009,256(4):954-957
We have investigated cathodeluminescence (CL) of Ge implanted SiO2:Ge and GeO2:Ge films. The GeO2 films were grown by oxidation of Ge substrate at 550 °C for 3 h in O2 gas flow. The GeO2 films on Ge substrate and SiO2 films on Si substrate were implanted with Ge-negative ions. The implanted Ge atom concentrations in the films were ranging from 0.1 to 6.0 at%. To produce Ge nanoparticles the SiO2:Ge films were thermally annealed at various temperatures of 600-900 °C for 1 h in N2 gas flow. An XPS analysis has shown that the implanted Ge atoms were partly oxidized. CL was observed at wavelengths around 400 nm from the GeO2 films before and after Ge−-implantation as well as from SiO2:Ge films. After Ge−-implantation of about 0.5 at% the CL intensity has increased by about four times. However, the CL intensity from the GeO2:Ge films was several orders of magnitude smaller than the intensity from the 800 °C-annealed SiO2:Ge films with 0.5 at% of Ge atomic concentration. These results suggested that the luminescence was generated due to oxidation of Ge nanoparticles in the SiO2:Ge films. 相似文献
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F. Evangelisti M.G. Proietti A. Balzarotti F. Comin L. Incoccia S. Mobilio 《Solid State Communications》1981,37(5):413-416
The structure of a-Ge as a function of the deposition temperature Ts has been studied by the EXAFS technique for the first time. The results demonstrate the sensitivity of EXAFS to structural differences in the medium range. The data provide strong evidence for a continuous transition from the amorphous to the crystalline phase over a temperature interval form 130°C to 300°C. The analysis of the data is in line with the microcrystal model of amorphous Ge films and allows an estimate of the average grain size for the lower range Ts used. 相似文献
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Hans Jørgen Vind Nielsen 《Journal of magnetism and magnetic materials》1979,12(2):187-190
Amorphous ribbons of nominal compositions Fe85-xCrxB15,x =5, 10, 15 and 20 at%, were produced by a continuous liquid quenching technique. The Curie temperatures were measured using several methods. A quite large decrease with increasing Cr-content is observed: 20 K/at% Cr around 300 K. The Curie temperatures are compared with those of similar metallic glass systems based on Fe and Cr reported in the literature. The crystallization temperatures determined from measurements of the electrical resistivity versus temperature at a heating rate of ≈10K/min are obtained as a function of Cr-content, showing an increase in stability between 10 and 15 at% Cr. Finally, the room temperature (≈295K) electrical resistivities of as quenched and crystallized samples are given. The resistivity of the as quenched ribbons in nearly independent of Cr-content (≈128 μΩ cm) while the resistivity of the crystallized ribbons show an increase of ≈2.7 μΩ cm/at% Cr. 相似文献
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C.-C. Kuo 《Applied physics. B, Lasers and optics》2008,91(3-4):511-516
Amorphous germanium (a-Ge) films in samples with or without an absorptive film are crystallized by short-pulse XeF excimer laser crystallization (ELC). An in situ time-resolved optical reflection and transmission (TRORT) monitoring system combining a cw He-Ne probe laser, a digital oscilloscope and two photodetectors is developed to investigate the melting and resolidification dynamics of Ge films during ELC. TRORT measurements reveal that the longest melt duration is prolonged from 250 to 1000 ns by adding absorptive films in the samples. Absorptive films are shown to be effective in improving the melt duration of the molten state and the grain size of polycrystalline Ge films. The grain size with a diameter of approximately 12 μm can be fabricated in the superlateral growth regime for 90-nm-thick a-Ge films at room temperature in air by single-shot ELC. 相似文献
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本文研究了非晶态离子导体Li2B2O4的离子电导率与温度的关系,特别着重于晶化前期的离子迁移特性。当温度低于TK(≈310℃)时,离子电导率遵从Arrhenius关系。当高于晶化温度(≈411℃)时,以晶态中的离子迁移为主。在Tkc时,电导率偏离热激活机制呈反常增高。我们把这一过程称为晶化前期过程。可以用自由体积模型进行描述。晶化前期又可分为两部分:当温度低于、Tp(≈380℃)时,由于自由体积的重新分布,导致了电导率的增高;当T>Tp时,出现了少量微晶,但晶化量小于5%,由于非晶母体与微晶之间的界面效应使得离子导电性显著增强。可以通过室温淬火,把晶化前期非晶态的状态保持到室温,从而有可能制备出离子电导率高于纯非晶态的材料。
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Semiconductor germanium (Ge) in contact with some metals, such as Al, Pd, and Au, etc., is a class of distinctive materials with non-integer dimensions (D) that differ from integer dimensional materials, such as nanoparticles (0D), nanowires/nanorods//nanotubes/nanoribbons (1D), and thin films (2D). In this article, we describe our efforts toward understanding the annealing strategies and perspectives of metal-induced crystallization for the amorphous Ge embedded in Al, Pd, and Au matrices prepared by high vacuum thermal evaporation techniques, highlighting contributions from our laboratory. First, we present the Al-induced crystallization of amorphous Ge and formation processes of fractal Ge patterns. In addition, the fractal Ge patterns induced by Pd nanoparticles with solid-state reactions will be summarized in detail. Temperature-dependent properties of resistance and fractal dimension in Pd/Ge bilayer films will be expounded. In particular, the nonlinear optical properties are discussed in detail. Finally, we will emphasize the in situ observations by transmission electron microscopy and multi-fractal analysis for the fractal Ge patterns induced by Au nanoparticles. Moreover, the polycondensation-type fractal Ge patterns with non-integer dimensions, thick branches and smooth edges, and metastable gamma-Au0.6Ge0.4 are further investigated. The computer simulation indicated that the experimental results are good agreement with the simulation patterns, which were carried out by a ripening mechanism of non uniform grains. This review may provide a novel insight to modulate their competent performance and promote rational design of micro/nanodevices. 相似文献