共查询到19条相似文献,搜索用时 97 毫秒
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本文介绍互不溶Sn-Al合金表面上Sn纳米线(直径为100 ~ 500 nm)自发生长的两种情况,它们都不需要模板和催化剂.通过SEM、TEM分析和对Al、Sn相的相互作用机理研究表明,这些Sn纳米线具有[200]生长方向,它们的生长与Sn熔点和Al-Sn共晶点的差异,以及Sn-Al合金(块体、薄膜)中存在的残余压应力有关.将含有Sn纳米线的Sn-Al薄膜作为锂离子电池负极材料进行电化学测试,在0.3~1.5 V vs.Li/Li+(Li/Li+为对电极和参比电极)电压范围循环时,它的稳定可逆容量为300 mAh/g.通过与纯Sn薄膜负极比较研究可知,Sn纳米线的一维特征有利于改善Li+的扩散动力学,从而提高Sn-Al薄膜电极的电化学性能. 相似文献
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ZnO纳米线阵列的侧面生长机理 总被引:3,自引:0,他引:3
通过一种简单的无催化剂存在的气相生长工艺制备了侧面长成梳状结构的ZnO纳米线阵列。沿[0001]方向生长的ZnO纳米线按照100~500nm的间隔有规律地排列在梳底一侧。单晶梳底沿着[2110]方向生长到±(0110)和±(0001)面终止。所得均一纳米线的直径和长度分别为40~100nm和0.5~2.0μm。纳米线阵列的侧面生长成为微米梳,是气体分子自组装成纳米线和一步法组装成微米结构的重要例子。本文详细讨论了ZnO纳米线阵列生长成为微米梳的生长机理。 相似文献
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采用溶胶-凝胶(sol-gel)自旋涂敷法在Si(100)基多孔氧化铝模版介质上制备了Pb(Zr0.53Ti0.47)O3(PZT)纳米铁电薄膜(厚度25nm).利用电化学方法在多孔氧化铝模版孔道内(孔径25nm)生长Au纳米线,作为底电板一部分.利用x射线衍射(XRD)、扫描电镜(SEM)及场发射透射电镜(FE-TEM)对PZT纳米铁电薄膜的生长行为、表面形貌和微结构进行了研究.XRD谱图表明PZT纳米铁电薄膜具有(111)择优取向;SEM像显示PZT纳米铁电薄膜结构致密,晶粒呈椭球状,平均尺寸为22nm.剖面TEM像证实PZT纳米铁电薄膜与Au纳米线直接接触,它们之间的界面呈现一定程度的弯曲;部分Au纳米线顶端出现分枝展宽现象.介电谱表明PZT纳米铁电薄膜的介电常数在低频区域(频率小于104 Hz)从760迅速下降到100,然后基本保持在100,直至测量频率升高到106 Hz.低频区域内介电常数的迅速下降是由于空间电荷极化机制所致;介电损耗在4 000 Hz附近出现峰值(来源于空间电荷的共振吸收)也证实了空间电荷极化机制的存在. 相似文献
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室温紫外纳米线纳米激光器 总被引:1,自引:0,他引:1
颜严 《激光与光电子学进展》2002,39(6):37-39
演示了半导体纳米线阵列中的室温紫外激射。利用简单的蒸汽传输冷凝技术制造了生长在蓝宝石基底上的自组织<0001>定向氧化锌纳米线。这种宽带隙半导体纳米线形成了直径20-50nm、长度达10μm的自然激光腔。在光激励下,观察到385nm的面发射激光行为,辐射线宽小于0.3nm。纳米线的化学灵活性和一维性使其成为理想的小型化激光光源。这种短波长纳米激光器可能有很多应用,包括光计算、信息存储和微量分析等。 相似文献
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自组装型SnO2纳米线超低浓度H2传感器的研制 总被引:1,自引:1,他引:0
采用FESEM及气敏传感器测试系统,研究了用自组装方式制备的SnO2纳米线气敏传感器的氢敏特性。结果表明:在工作温度为200℃时,对于超低浓度[(2~8)×10–6]的氢气具有0.58~1.00的探测灵敏度及3 s的响应时间和10 s的恢复时间。继而从气敏机制、自组装制备方式、SnO2纳米线的优良的比表面特性及其尺度(30~40 nm)低于德拜长度(43 nm)等角度,解释了此传感器对超低浓度氢气具有良好气敏特性的原因。 相似文献
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非晶SiO2纳米线的合成及其显微结构和光学性质的研究 总被引:1,自引:0,他引:1
本研究以硅片为衬底,热蒸发一氧化硅粉末在较低温度下合成了大量直径均匀的非晶SiO2纳米线.这些纳米线直径分布在15 nm~40 nm之间,长度几十微米.选区电子衍射(SAED)、能谱(EDS)、电子能量损失谱(EELS)分析结果表明这些纳米线为非晶SiO2纳米线.光致发光(PL)谱测试结果显示纳米线在波长550 nm处存在一个较强的PL峰.本文进一步指出了蒸发源SiO粉末的颗粒度和蒸发温度对纳米线生长有强烈的影响. 相似文献
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H.Q. Cao X.Q. Qiu B. Luo Y. Liang Y.H. Zhang R.Q. Tan M.J. Zhao Q.M. Zhu 《Advanced functional materials》2004,14(3):243-246
This paper reports the synthesis of tetragonal zirconia nanowires using template method. An as‐prepared sample was characterized by scanning and transmission electron microscopy. It was found that the as‐prepared materials were tetragonal zirconia nanowires with average diameters of ca. 80 nm and length of over 10 μm. The Raman spectrum showed peaks at 120, 461, and 629 cm–1, which are attributed to the Eg, Eg, and B1g phonon modes of the tetragonal zirconia structure, respectively. The UV‐vis absorption spectrum showed an absorption peak at 232.5 nm (5.33 eV in photon energy). Photoluminescence (PL) spectra of zirconia nanowires showed a strong emission peak at ca. 388 nm at room temperature, which is attributed to the ionized oxygen vacancy in the zirconia nanowires system. 相似文献
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采用简单的一步水热法直接在不锈钢基底上制备了不同形貌的SnO2纳米棒阵列。利用X射线衍射(XRD),扫描电镜(SEM)、透射电镜(TEM)、 分光光度计、场发射装置对材料的结构、形貌、光致发光谱和场发射特性进行了表征。XRD结果表明不锈钢基底上制备的样品为四方晶系金红石结构。SEM和TEM结果表明不同的反应条件下都能够在基底上大面积的垂直生长单晶SnO2纳米棒阵列,但是形貌和尺寸发生了改变(A:针尖状,B:铅笔状)。室温下的光致发光光谱(PL)表明两种样品在367、392、419 nm处分别存在较强的发射峰,并且紫外光峰强与可见光峰强比值较大,说明样品的结晶质量较好。场发射测试结果表明:两种样品的场发射都是通过电子隧道效应进行的,且样品A的场发射性能优于样品B。 相似文献
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4H-SiC/SiO2 nanowires are synthesized and the temperature-dependent photoluminescence (PL) properties of the nanowires are studied. Their structure and chemical composition are studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectra. At room temperature, an ul- traviolet PL peak and a green PL band are observed. From the PL spectrum measured in the temperature range from 80 K to 300 K, the free excition emission, donor bound excition emission and their multiple-phonon replicas have been observed in ultraviolet region, and their origins have been identified. Moreover, it has been found that the temperature dependence of the free exciton peak position can be described by standard expression, and the thermal activation en- ergy values extracted from the temperature dependence of the free exciton and bound exciton peak integral intensity are about 40 meV and 181 meV, respectively. 相似文献
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In this paper the effects of silicon substrates with different orientations on the morphological and optical properties as well as biaxial stress of ZnO nanowires were investigated. The ZnO nanowires were grown on Si(1 0 0) and Si(1 1 1) substrates by the vapor–solid (VS) method using a physical vapor deposition reactor. In addition ZnO nanowires were grown on Si(1 1 1) substrate by the vapor–liquid–solid (VLS) method using an Au film as catalyst, which were deposited on Si(1 1 1) substrate using a sputtering method, with the same conditions. Room temperature photoluminescence (PL) spectrum showed a stronger ultraviolet (UV) peak at 381 nm for the nanowires that were grown on Si(1 1 1) by the VS method than those that were grown on Si(1 0 0) with the same green emission (deep-level emission (DLE)) intensities at about 520 nm peak. On the other hand, the PL result of the ZnO nanowires, which were grown by the VLS method, showed the same intensities for the both UV and DLE peaks. Furthermore, the effects of silicon substrate orientation and Au catalyst on biaxial stress of the nanowires were studied by Raman spectrometer. It was discussed that Au catalyst was one of the important factors that could affect the biaxial stress value of the ZnO nanowires that were grown on Si substrates. 相似文献
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自催化方式制备ZnO纳米线及光致发光特性 总被引:1,自引:0,他引:1
采用化学气相沉积法,不用催化剂,在Si(111)基片上制备了ZnO纳米线。扫描电子显微镜(SEM)表征发现ZnO纳米线的直径在100nm左右。X射线衍射(XRD)图谱上只存在ZnO的(002)衍射峰。室温下光致发光谱(PL)中出现了389nm和357nm的紫外峰以及五个蓝光峰(450,468,474,481和491nm)。389nm峰为自由激子复合发射357nm峰是在LO声子的参与下,自由载流子碰撞形成自由激子过程的发光行为;468nm峰系电子从氧空位形成的浅施主能级向价带跃迁发光;450nm峰系电子从导带向锌空位形成的浅受主能级跃迁发光;474,481和491nm峰是声子伴线。 相似文献
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The controllable growth processes of ZnO nanowires by evaporation of metal zinc with high purity and its luminescence properties have been investigated in detail. Firstly, the power of ZnO nanowires with high yield and homogeneous dimension was synthesized using the special quartz boat at 600 °C. Then, the oriented ZnO nanowires with about 20 nm diameter were synthesized by using a 90 nm-thick layer of ZnO nanocrystals on the Si substrate as the seed layer. Both fabrication processes are repeatable and no catalysts are necessary. Finally, photoluminescence (PL) spectroscopy for ZnO nanowires using an He-Cd laser line of 325 nm as the excitation source were measured at room temperature and both samples showed a sharp strong ultraviolet (UV) near-band edge emission. However, different UV peak positions (385 nm for ZnO nanowire powder, 377 nm for ZnO nanowire array) can be observed. The size confinement effect for excitons and carriers is proposed to explain the blue shift of the near-band edge emission with decreasing size and the native defects are responsible for the green emission. 相似文献