共查询到20条相似文献,搜索用时 93 毫秒
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以硝酸锌为锌源,采用水热法合成由纳米晶粒聚集成的ZnO纳米微球,通过调节三乙醇胺与水的体积比得到不同粒径的ZnO微球,采用X射线衍射分析、红外光谱、扫描电镜和紫外-可见光谱表征样品。结果表明,制备的ZnO样品为六方纤锌矿结构;ZnO纳米微球生长机理是硝酸锌在三乙醇胺水溶液中水解生成ZnO纳米晶粒并定向聚集。 相似文献
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采用水热法制备了不同掺杂浓度的ZnS∶Cu(0~0.6%(原子分数))纳米晶。结果表明,ZnS∶Cu纳米晶为立方晶系闪锌矿结构,晶粒尺寸在3~4nm之间;相比未掺杂的ZnS纳米晶,掺杂ZnS∶Cu纳米晶在500nm处产生了发射光谱(PL)。这是由于发光中心位于446和468nm两个PL光谱与ZnS自身的缺陷有关,发光中心位于500nm的绿光为浅施主能级(S缺陷)与铜t2能级之间跃迁而产生。并且其发光强度随掺杂浓度显著增强,当浓度为0.4%(原子分数)时达到最大值,进而发生了浓度淬灭现象。 相似文献
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利用简单的碳热蒸发法在Si(100)衬底上成功制备了天线状的氧化锌纳米材料,并利用X光衍射、扫描电子显微镜、透射电子显微镜和光致发光谱对样品进行了结构表征和光致发光特性研究。实验结果表明:制备的单晶氧化锌材料具有纤锌矿结构,并且沿着[0001]方向择优生长;每个纳米结构有4个针足,每个针足的顶部直径约为5-50nm;室温光致发光谱中包含1个386nm附近的较强的近紫外发光峰和1个523nm附近的较弱的绿色发光峰,分别由自由激子复合和深能级发射引起。同时讨论了天线状的氧化锌纳米材料在高温低氧条件下的生长机理。 相似文献
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氧化锌纳米结构的电化学控制制备及其光致发光性能 总被引:1,自引:0,他引:1
利用电化学沉积法, 通过调节电解液浓度、时间、温度等因素, 在氧化铟锡(ITO)导电玻璃上制备了形貌不同的氧化锌(ZnO)纳米薄膜. 通过X射线衍射、扫描电镜、透射电镜、光致发光谱等测试手段对不同形貌的ZnO纳米薄膜进行了表征和研究. 研究表明, 在高于阈值电压的情况下氧化锌薄膜迅速生成, 微观形貌主要受电解质溶液的浓度影响, 随着电解质浓度的升高可分别获得胞芽状、棒状、片层状结构, 结合晶体生长理论探讨了不同形貌ZnO薄膜的成因. 室温光致发光谱显示片状的ZnO纳米薄膜在近带边有较强的宽化激发峰, 而可见区的发光峰受到明显抑制, 这一结构有望应用于光电器件、传感器等领域. 相似文献
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Mushroom-like ZnO microcrystals have been prepared via a solution calcination route, using Zn(NO3)2 as Zn source in the absence of any surfactants, templates or catalysts. This is the first example to prepare mushroom-like crystals as semiconductors, which are expected to show particular physical properties. The ZnO products were investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy and photoluminescence (PL) spectrum measurements. A suitable concentration of Zn(NO3)2 solution was important for the growth of the mushroom-like products. The reported synthetic procedure is straightforward and inexpensive, and thus can be readily adopted to produce large quantities of mushroom-like ZnO microcrystals. 相似文献
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Prabhakar Rai Suraj Kumar Tripathy Nam-Hee Park In-Hwan Lee Yeon-Tae Yu 《Journal of Materials Science: Materials in Electronics》2010,21(10):1036-1041
A simple CTAB-assisted hydrothermal synthesis of undoped and copper-doped ZnO nanorods is reported. The phase and structural analysis carried out by X-ray diffraction, shows the formation of hexagonal wurtzite structure of ZnO. Morphology of the ZnO nanorods was investigated by electron microscopy techniques which showed the formation of well dispersed regular shape ZnO nanorods of 100 ± 10 nm in diameter and 900 ± 100 nm in length. However, size of the copper doped ZnO nanorod slightly increased with increasing copper concentration. Furthermore, the selected area electron diffraction pattern and high resolution transmission electron microscopy reveal that both the undoped and copper doped ZnO nanorods were single crystalline in nature and preferentially grew up along [0001] direction. Optical property was investigated by photoluminescence spectroscopy. The effects of copper doping on the photoluminescence property of ZnO nanorods were investigated. 相似文献
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Yin S Chen Y Su Y Jia C Zhou Q Li S Xin M Kong W Zhang X Lü Y 《Journal of nanoscience and nanotechnology》2008,8(2):993-996
Well-aligned ZnO nanorods and nanopins are synthesized on a silicon substrate using a one-step simple thermal evaporation of a mixture of zinc and zinc acetate powder under controlled conditions. A self-assembled ZnO buffer layer was first obtained on the Si substrate. The structure and morphology of the as-synthesized ZnO nanorod and nanopin arrays are characterized using X-ray diffraction, and scanning and transmission electron microscopies, energy-dispersive X-ray spectroscopy, and photoluminescence spectroscopy. The influence of the background atmosphere on the two ZnO nanostructures has been studied. Two different growth mechanisms are mentioned to interpret the formation of ZnO nanorod and nanopin arrays in our work. The room-temperature PL features the ZnO nanorods exhibit only sharp and strong ultraviolet (UV) emission emissions, which confirms the better crystalline and optical quality than the ZnO nanopins. 相似文献
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Large-scale uniform nutlike ZnO microcrystals are successfully synthesized via a facile hydrothermal process at low temperature (95 °C). The structure and morphology of the ZnO products are characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The results reveal that the as-prepared ZnO products have average length of 2.2 µm and diameter of 1.8 µm, possessing a single crystal wurtzite structure. The possible formation mechanism of nutlike microcrystals is proposed. The samples exhibit excellent ethanol sensing properties at the operating temperature of 250 °C detecting ethanol as low as 1 ppm. 相似文献
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《Materials Letters》2006,60(9-10):1242-1246
PbS microcrystals including dendrites, multipods, flowers and cubes were prepared by the reaction of Pb(NO3)2 or Pb(CH3COO)2 and thiourea (NH2CSNH2) with acrylamide (AA) as surfactant through a simple hydrothermal process. The samples are characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Uniform PbS crystals were obtained at the temperature of 130–160 °C. It is found that thiourea, acrylamide and reaction temperature play important roles in the shape evolutions of PbS microcrystals. A possible formation mechanism of PbS microcrystals was discussed based on their shape evolutions. 相似文献
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Flower-like ZnO nano/microstructures have been synthesized by thermal treatment of Zn(NH3)42+ precursor in aqueous solvent, using ammonia as the structure directing agent. A number of techniques, including X-ray diffraction (XRD), field emission scan electron microscopy (FESEM), transmission electron microscopy (TEM), thermal analysis, and photoluminescence (PL) were used to characterize the obtained ZnO structures. The photoluminescence (PL) measurements indicated that the as-synthesized ZnO structures showed UV (∼375 nm), blue (∼465 nm), and yellow (∼585 nm) emission bands when they were excited by a He-Gd laser using 320 nm as the excitation source. Furthermore, it has been interestingly found that the intensity of light emission at ∼585 nm remarkably decreased when the obtained ZnO nanocrystals were annealed at 600 °C for 3 h in air. The reason might be the possible oxygen vacancies and interstitials in the sample decreased at high temperature. 相似文献
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Min Zhao Dapeng Wu Jiuli Chang Zhengyu Bai Kai Jiang 《Materials Chemistry and Physics》2009,117(2-3):422-424
Cup-like ZnO microcrystals were successfully synthesized by using a CTAB-assisted hydrothermal route. Zn(CH3COO)2·2H2O was used as the only precursor to generate cup-like ZnO microcrystals. The morphologies and structures of the samples were characterized by XRD and SEM. The XRD pattern shows that the cup-like ZnO microcrystals are hexagonal. The SEM investigation reveals that the as-prepared ZnO product has cup-like morphology. CTAB was found to play a crucial role in determining the cup-like morphologies. A possible formation process of the cup-like ZnO microcrystals was proposed. Optical property of the product was also investigated by fluorophotometer at room temperature. 相似文献
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《Materials Letters》2006,60(21-22):2777-2782
ZnO nanowires with high-aspect-ratio of up to ca. 600 were synthesized in a quaternary reverse microemulsion containing sodium dodecyl sulfate (SDS) / water / heptane / n-hexane via a hydrothermal method. SDS, as an anionic surfactant, plays an important role in the formation of morphologies. Subsequently, we studied lots of key influencing factors including the molar ratio (w) value of NaOH to Zn(OAc)2, the reaction temperature, and the instance without the quaternary reverse microemulsion. The selected-area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM) reveal the single-crystal nature of the ZnO nanowires. The morphologies and crystalline structure of the as-obtained products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and powder X-ray diffraction (XRD), respectively. Through this route, we can obtain a mass of products and the method is both convenient and reproducible. Finally, we measured the photoluminescence (PL) spectra and found that the ZnO nanowires exhibited green-orange emission at 525 nm and short ultraviolet emission at 380 nm and the ZnO nanomaterials with different aspect ratio (length to diameter) (L / D) showed PL intensity disciplinary change. Aiming at this phenomenon, we propose a reasonable mechanism to explain the PL spectra of the ZnO nanomaterials in detail. 相似文献
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Prabhakar Rai Jin-Nyeong Jo In-Hwan Lee Yeon-Tae Yu 《Materials Chemistry and Physics》2010,124(1):406-412
In the present work, we reported a novel method for the synthesis of well-dispersed flower-like ZnO microstructures derived from highly regulated, well-dispersed ZnO nanorods by using low temperature (100 °C) hydrothermal process and without using any additional surfactant, organic solvents or catalytic agent. The phase and structural analysis were carried out by X-ray diffraction (XRD) which confirms the high crystal quality of ZnO with hexagonal (wurtzite-type) crystal structure. The morphological and structural analyses were carried out by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) which indicate the formation of well-dispersed ZnO nanorods as well as flower-like ZnO. It has been shown that flower-like ZnO is made up of dozen of ZnO nanorods building block units. The high resolution transmission electron microscopy (HRTEM) and their corresponding selected area electron diffraction (SAED) pattern show that both ZnO nanorods and flower-like ZnO microstructures are single crystalline in nature and preferentially grow along [0 0 0 1] direction. Their optical property was characterized by photoluminescence spectroscopy; shows ZnO nanorods have only violet emission and no other emission while flower-like ZnO microstructures have a weak violet emission and a strong visible emission. A plausible growth mechanism of ZnO nanorods as well as flower-like ZnO microstructures has been given. 相似文献