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Mechanically tunable broadband terahertz modulator based on high-aligned Ni nanowire arrays
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We present a mechanically tunable broadband terahertz(THz) modulator based on the high-aligned Ni nanowire(NW)arrays. The modulator is a sandwich structure consisting of two polydimethylsiloxane layers and a central layer of highaligned Ni NW arrays. Our experimental measurements reveal the transmittance of THz wave can be effectively modulated by mechanical stretching. The NW density in arrays increases with the strain increasing, which induced an enhancement in the absorption of THz wave. When the strain increases from 0 to 6.5%, a linear relationship is observed for the variation of modulation depth(MD) of THz wave regarding the strain, and the modulated range is from 0 to 85% in a frequency range from 0.3 THz to 1.8 THz. Moreover, the detectable MD is about 15% regarding the 1% strain change resolution. This flexible Ni NW-based modulator can be promised many applications, such as remote strain sensing, and wearable devices. 相似文献
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Performance analysis of single-focus phase singularity based on elliptical reflective annulus quadrangle-element coded spiral zone plates
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Optical vortices generated by the conventional vortex lens are usually disturbed by the undesired higher-order foci,which may lead to additional artifacts and thus degrade the contrast sensitivity. In this work, we propose an efficient methodology to combine the merit of elliptical reflective zone plates(ERZPs) and the advantage of spiral zone plates(SZPs) in establishing a specific single optical element, termed elliptical reflective annulus quadrangle-element coded spiral zone plates(ERAQSZPs)... 相似文献
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用激光分子束外延,原子尺度控制的外延生长出多种钙钛矿氧化物异质结.X射线衍射和原子力显微镜测量结果表明,在Si基底上生长的SrTiO3和LaAlO3薄膜具有很好的外延结构和取向,其表面达到原子尺度的光滑.YBCO/SrNb0.01Ti0.99O3、La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3(LSMO/SNTO)等异质结,均观测到较好的p-n结I-V特性.首次观测到钙钛矿结构氧化物p-n结电流的磁调制和正巨磁电阻效应,在255K条件下,当外加磁场分别为5×10-4T、1×10-3T、1×10-2T和0.1T时,LSMO/SNTO p-n结的磁电阻变化率ΔR/R0达到:46.7%、59.7%、70.5%和83.4%;当外加磁场为3T时,在100K条件下,在LSMO/SNTO多层p-n异质结上观测465%的正磁电阻变化率. 相似文献
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无毒环保且稳定的非铅双钙钛矿材料因具有和铅基钙钛矿相似的三维结构,被认为是铅基钙钛矿材料最有前景的替代品之一.本文采用溶液法制备了一种新型非铅双钙钛矿材料Cs2TeCl6,利用金刚石对顶砧高压装置和高压原位同步辐射X射线衍射、紫外-可见吸收光谱技术,对其在高压下的晶体结构、光学带隙和电子结构演化进行了深入研究.研究表明,在实验压力范围(0—50.0 GPa)内Cs2TeCl6晶体结构并未发生改变,始终保持Fm-3m的结构对称性,表明该样品具有良好的稳定性; Cs2TeCl6的体积随压力的增加曲线变化比较平滑,通过三阶Birch-Mumaghan状态方程得到了体弹模量B0=(18.77±2.88) GPa; Cs2TeCl6为间接带隙半导体,在0—20.0 GPa范围内其光学带隙随着压力的增大逐渐减小,这与高压下八面体[TeCl6]2–的收缩相关.完全卸压后, Cs 相似文献
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硅基集成电路的发展和新一代栅极氧化物材料的研究现状 总被引:4,自引:0,他引:4
随着科学技术的进步和集成电路市场日益扩大的需求,硅基集成电路的集成度越来越高,而集成度的提高是以其核心器件金属氧化物半导体场效应晶体管(MOSFET)的特征尺寸逐渐减小为基础的。当栅极Si02介电层的厚度减小到原子尺度大小时,由于量子效应的影响,Si02将失去介电特性,因此必须寻找一种新的高介电常数(high—K)的氧化物材料来代替它。如今世界上许多国家都开展了替代Si02的介电氧化物材料的研究工作。文章介绍了栅极介电层厚度减小带来的影响,栅极Si02介电层的高尺氧化物材料的要求和租选,并对近期高介电常数氧化物材料的研究状况作了简要的介绍和评述。 相似文献
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开发高效、稳定的电催化剂是燃料电池走向实用的关键.为了解决催化剂因尺寸效应引起的催化活性和稳定性之间的矛盾,采用简便的一步溶剂热法设计合成了具有一维链状结构的Pt-Ni合金纳米颗粒催化剂.链状Pt-Ni纳米颗粒由平均尺寸约为10 nm的纳米颗粒和直径约为3 nm,长度为几百纳米的纳米线组装而成,该结构具有零维纳米颗粒高的比表面积和一维纳米线高的结构稳定性优势,可显著提高甲醇氧化反应的催化活性和稳定性,其质量活性和比活性分别是商业Pt/C纳米催化剂的5.7倍和7.6倍.经1000圈循环伏安测试后,该纳米材料仍保留91.2%的比活性,远高于商业Pt/C的4.4%.制备的一维链状结构很好地解决了纳米颗粒催化剂在反应中的团聚问题,为获得同时具有较高催化活性和稳定性的Pt基纳米催化剂提供了新的途径,有望实现大范围工业化应用. 相似文献
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Structure,Electrical,and Optical Properties of Nb-doped BaTiO3 Thin Films Grown by Laser Molecular Beam Epitaxy
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Structure,electrical,and optical properties of Nb-doped BaTiO3 (Nb:BTO) thin films on MgO substrates grownby laser molecular beam epitaxy with increasing Nb content were investigated.The Nb:BTO thin films with high crystallinity are epitaxially grown on MgO substrates.With more Nb-doped content,the impurity phases are found in Nb:BTO thin films.Hall measurement at room temperature confirms that the charge carriers of the Nb:BTO thin films are n-type.When the Nb-doped content increases,the carrier concentration and carrier mobility increase.Meanwhile the optical transmittance decreases with the increase of the Nb-doping,and the width of the forbidden band in each group is not affected by the presence of Nb in the samples.Raman spectra show that the structural phase transition may occur with the increase of the Nb-doping content,in the meantime more defects and impurities exist in the Nb:BTO thin films. 相似文献