制备工艺对锌铝氧化物(ZAO)粉末红外发射率的影响

采用液相共沉淀法制备了ZAO掺杂半导体粉末材料,系统研究了制备工艺对ZAO粉末红外发射率的影响.借助于TG-DTA、XRD、SEM对材料的热处理温度,晶体结构及表面形貌进行了考察,利用IR-2双波段发射率测量仪对ZAO粉末材料的红外发射率进行了测试.研究结果表明:当反应物终点pH值为8.5、反应时间为2.5h、煅烧温度为800℃,煅烧时间为2h、Al2O3的掺杂量为3%时所得的ZAO粉末的红外发射率最低;ZAO掺杂半导体粉末的晶体结构为ZnO的铅锌矿结构;粒子形状近似为椭圆形,平均粒径为5～10μm;在中红外(3～5μm)和远红外(8～14μm)波段均具有较低的红外发射率.     

类单晶氧化锌纳米棒的制备与表征

用简单的无催化剂、高温热蒸发方法制备氧化锌纳米棒,得到了具有良好晶体结构和规则外形的ZnO纳米棒,长度为(1-5)μm,直径约几十纳米.测量了ZnO纳米棒的光致发光特性.讨论了实验条件对纳米棒生长结果的影响,并对生长机理做了初步探讨.     

ZIF-8衍生La掺杂ZnO纳米颗粒的制备及其气敏性能

以ZIF-8及La掺杂ZIF-8为前驱体,经高温煅烧制备ZnO及La掺杂ZnO纳米颗粒.研究了La掺杂对ZnO纳米颗粒的形貌、晶体结构及气敏性能的影响.利用X射线衍射仪、扫描电子显微镜对材料的微结构进行表征,结果表明:La掺杂有利于获得更小粒径的类球形纳米结构,但La掺杂未改变ZIF-8及衍生ZnO纳米结构的晶体结构....     

微孔状ZnO薄膜的生长与光致发光性

使用Zn（CH3COO）2·2H2O和PVA水溶液混合的办法在Si衬底上生长了微孔结构的ZnO薄膜。样品的晶体结构、形貌及光致发光性使用XRD、SEM及PL谱进行表征。结果表明所制备的ZnO为六方纤锌矿型晶体结构，微孔的孔壁是由纳米颗粒聚集而成，颗粒尺寸大约为20nm,关于这种结构的形成，我们推测PVA在微孔结构的形成过程中起到了模板作用。     

氧化锌纳米棒有序阵列的制备及表征

氧化锌是一种重要的化合物半导体,其低维结构在微电子器件领域具有潜在的应用前景.在温和的条件下利用软化学方法在沉积了单层ZnO颗粒膜的玻璃衬底上制备了直径为70～300nm,长约1μm的氧化锌纳米棒有序阵列,讨论了颗粒膜对阵列生长的作用以及水浴温度对晶体结构和形貌的影响.结果表明,产物为纤锌矿结构;ZnO颗粒膜为阵列的生长提供了分布均匀且固定的形核中心,对阵列的有序生长起诱导作用;随着反应温度的升高,阵列直径变小且排列更加有序,但过高的温度会抑制ZnO晶体内部的c轴择优取向作用.研究了ZnO阵列的光致发光特性,初步讨论了其发光机理.     

分级微纳结构氧化锌的制备及其光致发光

采用低温热蒸发法研制出新型的ZnO分级微纳结构,利用场发射扫描电子显微镜和X射线衍射仪对其形貌与结构进行了表征,结果表明,所制备的分级结构为纯六方纤锌矿结构,由主干直径为1-3μm的ZnO微米线和表面的宽度为1μm、厚度约为100nm的晶片组成。用气-固（VS）机制阐明了ZnO分级结构的生长机理。在室温下,用近场光学显微镜测量了ZnO分级结构的光致发光谱,结果显示,在380nm处存在很强的近带隙发光峰,而508nm左右的缺陷发光很弱。     

表面活性剂对ZnO纳米晶形貌的影响

采用低温水热法，通过未添加表面活性剂、添加CTAB和添加SDS三种方式成功制备了各种ZnO纳米晶。利用X射线衍射（XRD）、拉曼光谱及扫描电镜（SEM）等测试手段对ZnO纳米晶的晶体结构和表面形貌进行了表征。结果表明，所有ZnO纳米晶均为高质量的六方纤锌矿结构，并呈现不同的形态，如花形、卷心菜形等。详细讨论了在不同表面活性剂水热生长的条件下，ZnO纳米晶的生长机制。此外，对ZnO纳米晶的光致发光性能进行了测量，发现所有产物均具有相似的光发射峰位。     

中空ZnO微球的制备及其光催化性能

以葡萄糖和醋酸锌为原料,采用模板法制备中空ZnO微球。并对所制样品进行表征,讨论了碳微球与醋酸锌物料比、煅烧温度、煅烧时间对ZnO催化剂光催化活性的影响。结果表明:在碳微球与醋酸锌物料比为1∶2、煅烧温度500℃、煅烧时间2h条件下,所制备的中空ZnO微球直径约为3~5μm,六方晶系结构,具有较好的光催化活性。     

基于表面微机械和压电薄膜技术的新型微谐振器

一种基于表面微机械和压电薄膜技术的体声波器件新结构，是在多晶硅膜片上演积氧化锌（ZnO）压电薄膜。ZnO膜是在c轴采用S枪磁控反应溅射定向生长，而多晶硅膜片采用表面微机械技术制备。采用平面工艺，对氧化牺牲层化学蚀刻和照像腐蚀，制得表面微结构，其性能与在硅膜片上各向异性的传统制作工艺比较，在制作简易性、生产量和可靠性方面都有重大进展。已制成的微谐振器尺寸为15μm×150μm和250μm×250μm，其谐振频率为559．05MHz。     

水热法一步合成氧化锌纳米棒及其场发射特性的研究

利用极其简单的方法,即将氯化锌溶液和氨水按一定配比混合进行水浴加热制备了ZnO纳米棒,其直径约为100nm.利用扫描电子显微镜和能谱仪对其结构和成分进行了分析.场发射测试结果表明,所制备的ZnO纳米棒有较低的开启场和阈值场,分别为2.7V/μm和4.95V/μm,其场增强因子为5390.这样高的场增强因子来源于氧化锌参差的层状结构.     

Fabrication and photoluminescence properties of graphite fiber/ZnO nanorod core-shell structures

Graphite fiber/ZnO nanorod core-shell structures were synthesized by thermal evaporation process. The core-shell hybrid architectures were comprised of ZnO nanorods grown on the surface of graphite fiber. In addition, Hollow ZnO hierarchical structure can be obtained by oxidizing the graphite fiber. Room temperature photoluminescence (PL) of the as-made graphite fiber/ZnO nanorod structures shows two UV peaks at around 3.274 eV and 3.181 eV. The temperature-dependent photoluminescence spectra demonstrate the two UV emissions are attributed to the intrinsic optical transitions and extrinsic defect-related emissions in ZnO. These hybrid structures may be used as the building block for fabrication of nanodevices.     

Structure and photoluminescence of S-doped ZnO nanorod arrays

Vertically aligned S-doped ZnO nanorod arrays have been successfully synthesized by hydrothermal method at 90 °C for 2 h. The obtained nanorod is ～ 70 nm in diameter and 1.2 μm in length. The XRD pattern and the Raman spectra indicate that the S-doped nanorod arrays are orientated at [001] and are single crystals with hexagonal wurtzite structure. The photoluminescence (PL) spectra show that S-doped ZnO nanorod arrays exhibit a relative weak ultraviolet (UV) emission, a violet emission and a strong green emission. The effects of S-doping on the structure and photoluminescence of ZnO nanorod arrays are discussed in detail.     

Optical properties of Ag doped ZnO nanocrystals prepared by hydrothermal and photodeposition method

Ag/ZnO nanocomposites have been synthesized by facile hydrothermal and photodeposition method. The effect of different concentration of Ag on the luminous intensity of ZnO was studied. The morphology, structure and optical properties of Ag/ZnO were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL), respectively. The XRD patterns show that intensities of diffraction peaks of Ag/ZnO were enhanced. The weak diffraction peak at 38.28° can be assigned to Ag₂O when the concentration of Ag increased to 0.09 M. PL results demonstrate that the UV luminous intensity of ZnO was significantly influenced by the concentration of Ag. The UV luminous intensity of Ag/ZnO nanocomposites increased by 11 times as compared with undoped ZnO when the concentration of Ag was 0.03 M due to the local surface plasma resonance effect of Ag nanoparticles.     

Formation and characterization of zinc oxide nanowires grown on hexagonal-prism microstructures

In this paper, zinc oxide (ZnO) micro- and nano-structures were synthesized through a chemical vapor deposition route. X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), and scanning electron microscopy (SEM) were used to study the samples’ phase, composition, purity, and structure. XRD analysis confirmed the formation of the wurtzite phase in all samples. SEM images revealed the formation of hexagonal-prism microstructures of ZnO. After we changed the conditions, nano-wires 40–50 nm in diameter appeared on these hexagonal-prism microstructures. Further, we investigated the photoluminescence properties of these structures at room temperature. The modified structures showed UV emission and strong blue-green photoluminescence line due to near-band emission and oxygen vacancies respectively.     

Synthesis and characterization of tetrapod-like Cu-ZnO nanowhiskers prepared by photo-reduction technique

Tetrapod-like Cu-ZnO nanowhiskers were synthesized by a photo-reduction technique in an aqueous solution containing Cu2+ ions. The XRD and TEM analyses revealed that the as-prepared ZnO nanowhiskers were covered by Cu coating or surrounded by Cu nanoparticles. Pure Cu nanoparticles were also produced in the solution by increasing the duration of xenon irradiation. These nanoparticles were amorphous and could be converted to crystalline structure by further electron beam irradiation. The photoluminescence measurement showed that the visible emission from the Cu-coated ZnO nanowhiskers had a blue shift when compared with that of the pure ZnO.     

Raman spectra and photoluminescence properties of In-doped ZnO nanostructures

In-doped ZnO nanostructures with four different morphologies, which are nanotetrapods, nanocombs, nanowires, and nanodisks, have been synthesized on silicon substrates by a simple thermal evaporation method. The XRD patterns show the In-doped ZnO nanostructures are all with the hexagonal wurtzite structure, and a slight difference in lattice parameters had been detected among the samples with various morphologies. The Raman spectra demonstrate that the vibrational mode of 2LA, which is very weak in undoped ZnO, was strongly enhanced with indium ion doping into ZnO structures. The photoluminescence (PL) measurements indicate that the nanodisks have a relative strong ultraviolet (UV) emission than other three kinds of samples.     

ZnO纳米带梳的制备及生长机理的研究

采用化学气相沉积(CVD)法成功制备出ZnO纳米带梳,实验过程不需要催化剂.X射线衍射仪(XRD)分析结果表明,ZnO纳米带梳为高度结晶的六方纤锌矿结构;利用扫描电子显微镜(SEM)观测,所制样品是由纳米带组成梳状形貌,纳米带梳的形成经过两个步骤:先通过VS机制形成微米带,而梳的齿通过自催化生长平行于(0001)极性面形成.对样品的光致荧光(PL)谱测量发现了位于～395nm和495nm处的室温光致发光峰.     

Synthesis and optical characteristics of ZnO nanocrystals

Zinc oxide nanomaterials with an average particle size of 20–30 nm are readily synthesized by the reaction of zinc acetate and oxalic acid under hydrothermal conditions. The samples are characterized by XRD, SEM, TEM, UV and photoluminescence (PL) studies. The average crystal size of the as prepared ZnO nanopowder is determined by XRD and the values are in good agreement with the TEM analysis. UV absorption spectra revealed the absorption at wavelength < 370 nm indicating the smaller size of ZnO nanoparticles. The quality and purity of ZnO nanomaterial crystalline samples are confirmed by photoluminescence spectra.     

Oriented growth of urchin-like zinc oxide micro/nano-scale structures in aqueous solution

The urchin-like ZnO microcrystals with high crystallinity decomposed from [Zn(OH)₄]^2? directly were obtained via a hydrothermal method. The morphology, particle size, crystalline structure and fluorescence of the as-prepared ZnO were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and photoluminescence (PL) analyses. The results demonstrated that the urchin-like ZnO crystals with wurtzite structure had a narrow distribution in size, which could be adjusted in the range of 30–80 μm by varying reaction time. Broad visible light emission peak was also observed in the PL spectra of the synthesized ZnO products. A multistep growth process about how to form such a structure was proposed.     

Synthesis and Characterization of Transition Metals Doped ZnO Nanorods

Different morphologies of undoped and transition metals(Mn,Co and Ni) doped one-dimensional(1D) ZnO nanocrystals were successfully synthesized by chemical method in an air atmosphere using polyvinylpyrrolidone(PVP) as a surfactant.The structure and optical properties were studied by scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),thermal gravimetric analysis(TGA),ultraviolet visible(UV-vis) absorption spectra and photoluminescence(PL) spectra.The doped ZnO nanorods exhibited a blue-shifted band gap and enhanced ultraviolet(UV) emission.In addition defect related emission was observed for the doped ZnO.