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1.
利用有限元分析法对镶嵌在Lu2O3薄膜中的Au、Cu、Pt、Co金属纳米颗粒的应变场分布进行分析.分析表明:金属纳米颗粒在生长过程中受Lu2O3薄膜的压缩应力作用,从而在纳米颗粒内部和表面产生相应应变,应变分布与金属纳米颗粒的杨氏模量和泊松比有关.杨氏模量大的金属纳米颗粒表面应变和内部应变差异较大;而杨氏模量小的金属纳米颗粒内外应变差相对较小.随着金属纳米颗粒在基体材料内部不断生长,其受到的偏应变也逐渐增大.金属纳米颗粒生长过程中的这种偏应变的存在和变化将极大地影响其内部晶格结构和表面形貌,进而影响金属纳米颗粒的性能.  相似文献   

2.
Fe纳米颗粒嵌埋对类金刚石薄膜结构及电学性能的影响   总被引:1,自引:0,他引:1  
 采用脉冲激光气相沉积方法制备了不同Fe嵌埋浓度的Fe: DLC多层纳米复合薄膜。用X射线光电子能谱仪(XPS)对薄膜的组成成分进行分析。利用透射电子显微镜(TEM)、拉曼光谱、电流-电压曲线研究Fe纳米颗粒嵌埋对薄膜的微观结构及电学性能的影响。XPS和TEM表明,Fe纳米颗粒周期性地均匀地嵌埋在碳薄膜中。拉曼光谱表明薄膜中的C为典型的类金刚石结构,Fe纳米颗粒促进芳香环式结构的形成,薄膜结构的有序度提高。电流 电压曲线表明,Fe纳米颗粒的嵌埋导致薄膜的室温电导率增加。  相似文献   

3.
Fe纳米颗粒嵌埋对类金刚石薄膜结构及电学性能的影响   总被引:2,自引:2,他引:0  
采用脉冲激光气相沉积方法制备了不同Fe嵌埋浓度的Fe: DLC多层纳米复合薄膜。用X射线光电子能谱仪(XPS)对薄膜的组成成分进行分析。利用透射电子显微镜(TEM)、拉曼光谱、电流-电压曲线研究Fe纳米颗粒嵌埋对薄膜的微观结构及电学性能的影响。XPS和TEM表明,Fe纳米颗粒周期性地均匀地嵌埋在碳薄膜中。拉曼光谱表明薄膜中的C为典型的类金刚石结构,Fe纳米颗粒促进芳香环式结构的形成,薄膜结构的有序度提高。电流 电压曲线表明,Fe纳米颗粒的嵌埋导致薄膜的室温电导率增加。  相似文献   

4.
游荣义  黄晓菁 《计算物理》2013,30(4):582-586
基于均匀外电场中金属纳米半球颗粒按一定对称性从平面衬底生长出的表面结构,建立纳米半球颗粒表面附近近场电势的理论模型.采用数值计算方法得到近场电势的空间分布,并以三维曲面的形式给出.结果表明:电势分布呈现明显的几何对称性.结果为解释与纳米结构薄膜表面有关的各种异常现象提供依据,为纳米结构薄膜材料的应用研究提供参考.  相似文献   

5.
利用柔性电子技术对半导体材料性能调控研究具有重大的科学意义及应用价值.该研究一方面突破了传统应变工程中受限于无机材料硬而脆的特性,且引入应变多为固定值的局限;另一方面也为基于无机功能材料的可延展柔性电子器件在大变形环境下的性能评估提供了理论基础.因此,柔性电子技术为针对半导体材料或其他功能材料的应变调控提供了一种新方法,将有望应用在诸多需要材料性能周期性改变的新颖领域之中.本文将首先简介柔性无机电子技术,并对其中的两大关键技术:基于纳米金刚石颗粒的减薄及转印技术进行重点阐述,并探究两大关键技术对半导体电子器件性能的影响;随后介绍半导体材料近些年在应变-能带结构耦合关系方向的研究成果,并以基于屈曲砷化镓纳米薄膜条带及量子阱结构的研究为例,阐明柔性电子技术运用于半导体材料性能调控的独特优势;最后展望应变调控半导体特性的应用方向与发展前景.  相似文献   

6.
采用脉冲激光沉积法,在MgO(100)面上外延生长了FePt:MgO多层纳米复合薄膜,FePt成分为Fe48Pt52.FePt纳米颗粒周期性嵌埋于单晶MgO外延层中.原位反射式高能电子衍射分析结果表明,MgO外延层呈层状生长,而FePt纳米颗粒呈岛状生长.在整个FePt:MgO纳米复合薄膜的生长过程中,成功实现了层状-岛状生长模式的交替控制.高分辨透射电子显微镜分析结果表明,退火热处理后,结晶完整的L10-FePt纳米颗粒粒径约为5 nm,呈扁平六角形状,在MgO基底上形成逐层排列的纳米点阵.磁滞回线结果表明,退火后薄膜矫顽力增大,有序度提高,磁性增强.  相似文献   

7.
金局域表面等离激元增强砷化镓发光特性   总被引:1,自引:0,他引:1  
研究了金纳米颗粒局域表面等离激元共振耦合效应,并实现了砷化镓薄膜的近场发光增强.通过理论计算金纳米颗粒的吸收光谱及电场分布,分析金属纳米颗粒形貌尺寸的改变对等离激元共振频率调控及局域场增强效果的影响,模拟半径为50nm的金颗粒并实现了35倍近场增强效果.通过对双球型的模拟,分析了一种金纳米颗粒增强GaAs的积极方式,即密集颗粒之间的近场耦合形成的"hotspots".此外,研究了不同溅射时间及快速退火对金纳米颗粒吸收特性的影响,发现金纳米颗粒吸收峰位主要位于560~680nm波段,而且随着溅射时间的增加发生红移现象.经过快速退火处理后,金纳米颗粒吸收峰位蓝移到510~550nm波段,形成与532nm激发波长相匹配的共振吸收峰.最后,实现砷化镓薄膜9.6倍的光致发光增强.  相似文献   

8.
模板技术制备一维纳米纤维及其阵列   总被引:2,自引:0,他引:2  
杨正龙  牛忠伟  杨振忠 《物理》2004,33(7):477-479
以阳极多孔氧化铝膜为模板 ,制备了一系列一维结构材料及其阵列体系 ,材料的结构和阵列方式可调 .主要包括两方面内容 :通过功能单体的自由基聚合 ,制备了核壳结构的双重凝胶纳米纤维PDMA/PNH4AA及其阵列 ,控制氧化铝膜表面的润湿性 ,双重凝胶纳米纤维的核壳结构可以发生相反转 ,通过银离子与PNH4AA相的选择性复合 ,制备了柔性银纳米纤维或管 ;结合嵌段共聚物的自组装和无机物的溶胶 /凝胶过程 ,制备了一维有序介孔二氧化硅及其阵列体系 ,改变嵌段共聚物的浓度 ,可以控制二氧化硅的介观结构 .此材料易于进行异质复合 ,因而便于制备功能性一维复合材料及其阵列体系  相似文献   

9.
利用时域有限差分算法(FDTD)对微纳结构靶的光场分布进行仿真模拟,探究微纳结构靶中的光传输机制,分析材料特性和结构参数对光传输特性和光场分布的影响。基于光场分布及演化的仿真模拟结果,对比半导体氧化铝、绝缘体二氧化硅和金属铜三种导电性不同的材料上纳米线和纳米孔阵列微纳结构靶的激光传输特性,分析光传输过程中的光场分布变化。研究结果表明,通过改变氧化铝和二氧化硅纳米孔(线)阵列结构靶中孔洞(纳米线)直径和间距等结构参数,可以实现对微纳结构靶中光传输特性和光场分布的调制,实现光场在介质材料和真空区域间的周期振荡分布,或是以一种稳定形态传输;激光在铜纳米孔阵列中传输时,透光性随孔洞半径的增加而增加。基于光场分布及演化的仿真模拟结果,对比不同材料、不同微纳结构靶的激光传输演化特性,给出物理图像及对应现象规律,根据光场调控需求,给出微纳结构靶设计。  相似文献   

10.
纳米团聚生长的多重分形谱   总被引:2,自引:0,他引:2       下载免费PDF全文
邵元智  钟伟荣  任山  蔡志苏  龚雷 《物理学报》2005,54(7):3290-3296
采用小角x射线散射(SAXS)方法,对两类具有代表性的纳米团聚的生长分形进行了表征.一 类为用化学方法 (水合肼溶液还原法) 制备的纳米金属Ni粉;另一类通过物理方法(纳米晶 化处理),由非晶基体相中生长纳米晶相、形成非晶/纳米晶双相结构的Finemet (Fe73 .5 Cu1Nb3Si13.5B9) 合金.上述两 类材料的纳米团聚在生长过程中都存在 明显元素扩散迁移,形成在1—100 nm范围内的元素分布非均匀区域.这些元素分布的非均匀 区域具有多重质量生长分形特征,其尺度大小和分布方式对最终的材料的物理性能至关重要 .SAXS方法是表征这类具有分形生长特征的纳米团聚微观结构信息的强有力手段.从方法论的 角度详述了从SAXS测量到获得多重分形谱的处理过程,这一实验研究分析手段对于定量考察 纳米微结构形貌的生长机理和性能的其他研究课题有一定的帮助作用. 关键词: 纳米材料 分形生长 小角x射线散射 磁性材料  相似文献   

11.
Growth of nanoparticles embedded in a host matrix can lead to substantial strain. Ge/GeO2 core/shell nanoparticles embedded in amorphous Al2O3 matrix is fabricated by the pulsed laser deposition method and rapid thermal annealing technique, which is confirmed by the experimental HRTEM result and consistent with Zhdanov׳s theoretical prediction. A finite-element calculation is performed to investigate the tuning effect on the strain by the morphology evolution of the Ge/GeO2 core/shell nanoparticle embedded in Al2O3 matrix. The simulated result indicates that the strain at the interface between the core and the shell strongly depends on the morphology of the nanoparticles. Moreover, it can be found that there is a dramatic transformation of the strain on Ge core from tensile to compressive strain during the shrinkage of Ge core and the expansion of GeO2 shell. The simulated results indicate that the strain can be designed by tuning the morphology of the nanoparticles, which provides an opportunity to engineer the properties of the nano-sized core/shell structures.  相似文献   

12.
Optical properties of Au nanoparticle composites and a grid structure of Cu nanoparticle composite were studied. Negative ion implantation was applied to synthesize Au and Cu nanoparticles in amorphous SiO2 and Al2O3. Au nanoparticles were embedded within a depth of 30 nm by 60keV Au implantation. The surface plasmon resonance (SPR) of Au:SiO2 and Au: Al2O3 composites shifted to red and to blue, respectively, compared to calculated ones by the Mie theory. Optical nonlinearity was measured with pump-probe femtosecond spectroscopy and the transient spectrum of Au: Al2O3 composite presented a large red shift from the SPR peak. Image mapping of far-field transmitted intensity of Cu-implanted SiO2 with a fine grid structure drawn by laser-lithography was observed by a scanning near-field optical microscopy (SNOM) system.  相似文献   

13.
The as-prepared alumina/silica (Al2O3/SiO2) composite nanoparticles were synthesized with a hydrothermal method and modified by silane coupling agent. The tribological properties of the modified Al2O3/SiO2 composite nanoparticles as lubricating oil additives were investigated by four-ball and thrust-ring tests in terms of wear scar diameter, friction coefficient, and the morphology of thrust-ring. It is found that their anti-wear and anti-friction performances are better than those of pure Al2O3 or SiO2 nanoparticles. When the optimized concentration of nanoparticle additive is 0.5 wt.%, the diameters of wear scar and friction coefficients are both smallest. Such modified composite nanoparticles can adsorb onto the friction surfaces, which results in rolling friction. Therefore, the friction coefficient is reduced.  相似文献   

14.
SiO2 nanocrystals embedded in Lu2O3 thin film were fabricated using pulsed-laser deposition method. Two dimensional finite element calculations clearly reveal that SiO2 nanocrystals certainly experienced great compressive stress in Lu2O3 thin film. This may lead to a great deal of stress-induced defects at the interface of SiO2 nanocrystals embedded in Lu2O3 thin film and thus induced the observed photoluminescence peak and charge storage properties. The findings presented here indicate that the matrix environment of the nanocrystals plays a significant role in determining their electrical and optical properties.  相似文献   

15.
Ge nanocrystals embedded in SiO2 and Lu2O3 thin films were fabricated using a pulsed laser deposition method. Two dimensional finite element calculations and Raman spectra clearly revealed that the Ge nanocrystals certainly experienced greater compressive stress in a Lu2O3 thin film than in a SiO2 thin film. This may lead to much more stress-relaxing defects at the interface of Ge nanocrystals embedded in a Lu2O3 thin film and thus enhances the intensity of defect-related photoluminescence. The findings presented here indicate that the matrix environment of the nanocrystals plays a significant role in the defect-related photoluminescence property.  相似文献   

16.
High-quality ZnO thin films were grown on single-crystalline Al2O3(0001) and amorphous SiO2/Si(100) substrates at 400–640 °C using laser molecular beam epitaxy. For film growth, the third harmonics of a pulsed Nd:YAG laser were illuminated on a ZnO target. The ZnO films were epitaxially grown on Al2O3(0001) with the narrow X-ray diffraction full width at half maximum (FWHM) of 0.04° and the films on SiO2/Si(100) exhibited a preferred c-axis orientation. Furthermore, the films exhibited excellent optical properties in photoluminescence (PL) measurements with very sharp excitonic and weak deep-level emission peaks. At 15 K, PL FWHM values of the films grown on Al2O3(0001) and SiO2/Si(100) were 3 and 18 meV, respectively. Received: 8 May 2001 / Accepted: 18 September 2001 / Published online: 20 December 2001  相似文献   

17.
The formation and optical response of VOx nanoparticles embedded in amorphous aluminium oxide (Al2O3) thin films by pulsed laser deposition is studied. The thin films have been grown by alternate laser ablation of V and Al2O3 targets, which has resulted in a multilayer structure with embedded nanoparticles. The V content has been varied by changing the number of pulses on the V target. It is found that VOx nanoparticles with dimensions around 5 nm have been formed. The structural analysis shows that the vanadium nanoparticles are oxidized, although probably there is not a unique oxide phase for each sample. The films show a different optical response depending on their vanadium content. Optical switching as a function of temperature has been observed for the two films with the highest vanadium content, at transition temperatures of about −20 °C and 315 °C thus suggesting the presence of nanoparticles with compositions V4O7 and V2O5, respectively.  相似文献   

18.
This article describes the ultraviolet (UV) protection of MgO and Al2O3 nanoparticles embedded electrospun polyacrylonitrile (PAN) nanofibrous mats. UV radiation is a harmful part of sunlight and prolonged exposure to it can cause serious skin damages. In this research, nanofibrous mats consisting of nanofibers with different diameters containing different amounts of MgO, Al2O3, MgO Plus, and Al2O3 Plus nanoparticles were produced, and their UV-protection was measured. The specific surface area of MgO, MgO Plus, Al2O3, and Al2O3 Plus nanoparticles was 230, 600, 275, and 550 m2/g, respectively. The mean diameter of electrospun PAN nanofibers embedded with metal oxide nanoparticles was in the range of 665–337 nm. The results showed that the UV-protection (shielding) capability of the mats strongly depends on fiber diameter; in fact a thin mat of nanofibers has a much stronger UV-protection in comparison to a thicker mat composed of regular fibers. UV transmission is reduced as a result of embedding MgO and Al2O3 nanoparticles in the electrospun PAN nanofibrous mats. MgO Plus and Al2O3 Plus show higher UV-protection than MgO and Al2O3.  相似文献   

19.
The optical properties of metallic tin nanoparticles embedded in silicon-based host materials were studied. Thin films containing the nanoparticles were produced using RF magnetron sputtering followed by ex situ heat treatment. Transmission electron microscopy was used to determine the nanoparticle shape and size distribution; spherical, metallic tin nanoparticles were always found. The presence of a localized surface plasmon resonance in the nanoparticles was observed when SiO2 and amorphous silicon were the host materials. Optical spectroscopy revealed that the localized surface plasmon resonance is at approximately 5.5 eV for tin nanoparticles in SiO2, and at approximately 2.5 eV in amorphous silicon. The size of the tin nanoparticles in SiO2 can be varied by changing the tin content of the films; this was used to tune the localized surface plasmon resonance.  相似文献   

20.
All-nanoparticle multilayer films were prepared by layer-by-layer deposition of SiO2 and Al2O3 nanoparticles onto polyester (PE) substrate. The top-most SiO2 (and Al2O3) layer was characterized using ToF-SIMS and SEM. An element-specific homogeneity index obtained by ToF-SIMS measurement provides clue to the formation mechanism. Experimental results from ToF-SIMS and SEM accord well with molecular dynamics simulation results, demonstrating the potential of using ToF-SIMS to study all-nanoparticle multilayer films.  相似文献   

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