一维纳米氧化锌的制备及应用研究进展

本文对一维纳米氧化锌的制备方法进行了综述,包括气相法、液相法和模板法;重点讨论了一维纳米氧化锌在太阳能电池、传感器、多功能纺织品以及有机物光催化降解等方面的应用;指出了一维纳米氧化锌制备中存在的问题,并对其后续发展进行了展望.     

聚乙烯醇为助剂水热法制备氧化锌纳米棒

一维结构的纳米氧化锌具有独特的电子和光电性能,在众多领域有着广阔的应用前景,故而对其合成方法的研究十分重要.本文中以聚乙烯醇作为修饰剂,通过水热法在较低的反应温度下制备了一维氧化锌纳米棒.分别用透射电镜、选区电子衍射和X射线衍射对产物形貌与结构进行了表征.研究发现,以聚乙烯醇为助剂在120℃反应24h可制备出具有六方结构的氧化锌纳米棒,其直径为50～80nm、长度为1～2μm.实验表明,聚乙烯醇在一维结构合成过程中起到关键作用,以Zn(0H)2为水热反应前驱体可制备出品质较高的一维氧化锌纳米棒.     

一维纳米稀土氧化物的研究进展

概述了国内外在一维纳米稀土氧化物(纳米管、纳米棒、纳米线)方面的研究现状,介绍了硬模板法、软模板法、水热法、超声法和微乳液法制备一维纳米稀土氧化物的工艺方法和机理,并对这些方法的优缺点进行了比较,指出了当前一维纳米稀土氧化物合成中存在的不足,并对一维稀土纳米氧化物的应用作了展望.     

铝共掺杂调制ZnO∶Mn纳米棒阵列的磁学和电学特性

采用磁控溅射方法制备了锰掺杂氧化锌和铝、锰共掺杂氧化锌纳米棒阵列并详细研究了它们的电学和磁学特性。微结构测试的结果表明,掺杂后的氧化锌纳米棒阵列保持了纤锌矿晶体结构,掺杂锰离子和铝离子占据了晶体中锌离子的位置实现了替位式掺杂。磁学性质测试结果表明铝、锰共掺杂氧化锌纳米棒在室温下具有明显的铁磁性,饱和磁矩为0.33μB/Mn atom,是居里温度高于室温的一维稀磁半导体材料。电学性质测试结果表明铝的共掺杂可以使得锰掺杂氧化锌纳米棒的电阻率降低4个数量级,使得铝、锰共掺杂氧化锌纳米棒有可能在未来自旋电子器件中作为高效自旋注入元器件得到广泛应用。     

高频热等离子体气相合成一维纳米氧化锌研究

把锌粉原料加入到高频常压热等离子体弧中,使锌粉加热气化,然后与加入等离子体反应器中的氧气反应,合成出了直径为50nm、长度超过2靘的一维棒状纳米氧化锌.研究了氧分压和锌粉加料速度对合成产物形貌的影响,结果表明,通过控制这些参数,可以调控合成的氧化锌纳米棒长径比.采用XRD、SEM、TEM和HRTEM对产物的形貌和结构进行了表征,并衷征了合成的氧化锌纳米棒的光致发光性能.     

氧化锌纳米棒形貌对ZnO/Cu2O异质结太阳能电池光伏性能的影响

采用电化学沉积法制备了ZnO纳米棒,首先讨论了电化学沉积参数对氧化锌(ZnO)纳米棒形貌的影响,并对不同长度ZnO纳米棒的光吸收和反射等性质进行了研究.实验发现沉积时间是影响纳米棒长度、直径的重要因素,ZnO纳米棒的微观形貌对其光学性质有重要影响.然后以氧化锌纳米棒为n型材料,以氧化亚铜为p型材料,通过电化学沉积法构筑了ZnO/Cu2O异质结太阳能电池,并测试了其光伏性能,研究表明增长纳米棒阵列的长度使得开路电压、短路电流密度及光电转换效率等性能得到提升.最后,综合分析了氧化锌纳米棒形貌与所组装电池的性能之间的关系,发现调控氧化锌纳米棒的形貌是提高ZnO/Cu2O异质结太阳能电池光伏性能的有效途径.     

中科院纳米氧化锌材料研究取得重要进展

据有关媒体报导，中科院力学所科研人员利用气相沉积法，成功地合成了多种形貌的微纳米氧化锌材料，比如纳米线、纳米棒、纳米锥、四足纳米氧化锌等，还实现了纳米氧化锌在碳纳米管上的直接生长，并制备出多种独特形貌的氧化锌微纳米材料，通过这种方法合成出来的材料具有很强的发光性能和催化活性。准一维纳米材料由于量子尺寸效应具有许多特异的物理、化学特性，是研究电子传输行为、光学特性和力学性能等物理性质的理想系统，在构建纳米电子和光学器件方面具有很大的应用潜力，近年来受到各界的广泛关注。纳米氧化锌特有的量子尺寸效应、界面效应和耦合效应，使其在紫外激光器、光波导器件、发光元件、表面声波元件、太阳能电池窗口材料、压敏电阻及气体传感器等方面有着广泛的用途，被称为“第三代半导体材料”。     

一维碳化硅纳米材料的研究进展

介绍了具有一维纳米结构的碳化硅(SiC)如SiC纳米棒、纳米线、纳米管、纳米带的制备方法,着重介绍了碳纳米管模板生长法、碳还原法、激光烧蚀法、电弧放电法、流动催化剂法和热解有机前驱体法以及它们的生长机理,并对这几种方法的优缺点进行了分析,指出了目前研究一维纳米SiC中存在的问题和未来发展方向.     

化学浴沉积过程中的氧化锌微米棒与纳米棒研究

采用化学浴沉积法在氧化锌种子层上制备了整齐有序且具有c轴取向的氧化锌纳米棒,同时还出现了自由分布的微米棒,其生长速度高于纳米棒,且生长模式符合扩散控制"Ostwald熟化"机制,但纳米棒生长过程的影响因素除扩散过程外还有形核密度、生长界面的反应动力学等.并研究了氧化锌纳米棒的微观结构和光学性质.     

氧化锌纳米棒微球的水热制备及其气敏性质研究

以Zn粉为原料,采用水热法制备了由氧化锌纳米棒自组装而成的氧化锌纳米棒微球和氧化锌亚微米棒,对氧化锌纳米棒微球进行了镍掺杂,用x射线衍射仪和扫描电镜对产物的结构和微观形貌进行了表征,探讨了反应机理,并测试了其气敏性质.研究发现,氧化锌纳米棒微球具有良好的气敏性质,对酒精和汽油具有较高的灵敏度,镍的掺杂明显提高了氧化锌纳米棒微球在酒精和汽油之间的选择性.     

Synthesis and Luminescent Properties of Planar-tip and Tapered-tip ZnO Nanorod Arrays

Vertically aligned ZnO nanorods were synthesized on a-plane sapphire via a metal catalyzed vapor phase transport and condensation process in a two-zone vacuum furnace. Planar-tip and tapered-tip ZnO nanorods were successfully synthesized by utilizing different source materials under the same growth conditions. The growth mechanisms were proposed to be vapor-liquid-solid （VLS） process for planar-tip ZnO nanorods and a combination of VLS and self-catalyzed processes for tapered-tip ZnO nanorods, From cathodoluminescence （CL） measurements, tapered-tip ZnO nanorods have more intense green emission than planar-tip ZnO nanorods, and therefore possess higher oxygen vacancy concentration than planar-tip ZnO nanorods. From CL characteristics, well-aligned planar-tip ZnO nanorods shall serve effectively as laser source, while well-aligned tapered-tip ZnO nanorods are suitable for direction-related optical applications.     

Fabrication of vertically aligned ultrafine ZnO nanorods using metal-organic vapor phase epitaxy with a two-temperature growth method

We report the fabrication of vertically aligned ultrafine ZnO nanorods using metal-organic vapor phase epitaxy and applying a two-temperature growth method. First, thick nanorods were grown vertically on the substrate at a lower temperature. Then, ultrafine ZnO nanorods with an average diameter of 17.7?nm were grown from the tips of the thick nanorods at a higher temperature. The direction of the ultrafine ZnO nanorods followed that of the preformed vertically aligned thick nanorods. Electron microscopy revealed that the ultrafine nanorods were single crystals and the growth direction was along the c axis. Excellent photoluminescence characteristics of the nanorods were confirmed.     

Elemental vapor-phase synthesis of nanostructured zinc oxide

We systematize experimental data on the elemental vapor-phase synthesis of zinc oxide nanocrystal arrays on substrates. This process may yield nanostructures differing in shape and dimensions, in particular, well-aligned ZnO nanorod arrays. A model is proposed in which aligned zinc oxide nanorod arrays may grow by the vapor-liquid-solid (VLS) mechanism, and liquid zinc nanodroplets forming on the substrate surface at the beginning of the process catalyze one-dimensional growth. The VLS process is accompanied by zinc oxide deposition onto the lateral surface of the nanorods from the vapor phase. The relative rates of these processes influence the shape of the nanorods and the thickness of the polycrystalline underlayer. Optimizing the deposition conditions, one can grow uniform arrays of aligned high-quality ZnO nanorods with no catalysts and with no special substrate preparation steps.     

Zinc oxide nanostructured biosensor for glucose detection

Zinc oxide （ZnO） nanocombs were fabricated by vapor phase transport, and nanorods and hierarchical nanodisk structures by aqueous thermal decomposition. Glucose biosensors were constructed using these ZnO nanostructures as supporting materials for glucose oxidase （GOX） loading. These ZnO glucose biosensors showed a high sensitivity for glucose detection and high affinity of GOX to glucose as well as the low detection limit. The results demonstrate that ZnO nanostructures have potential applications in biosensors.     

Growth behavior and characteristics of one dimensional ZnO nanostructures by metalorganic chemical vapor deposition

The ZnO nanorods have been grown on silicon substrates by a metalorganic chemical vapor deposition (MOCVD) process with/without Au catalytic layer. The growth behavior of ZnO nanorods changed with the catalytic layer. The presence of Au catalyst complicated the growth direction of ZnO nanorods in the MOCVD methods. The ZnO nanorods had single crystalline atomic structure and pure compositions without impurities and strong and narrow excitonic emission. We investigated the growth behavior of the ZnO nanostructures which are leading candidate for optical applications.     

Fabrication of ZnS/ZnO hierarchical nanostructures by two-step vapor phase method

A simple two-step vapor phase method is presented to fabricate ZnS/ZnO hierarchical nanostructures in bulk quantities. That is ZnS nanobelts were first synthesized and then used as substrate for growth of ZnO nanorod arrays. Investigation results demonstrate that the polar surfaces of ZnS nanobelts could induce a preferred asymmetric growth of ZnO nanorods on the side surfaces. But it is believed that if the local concentration of ZnO was high enough, ZnO nanorods could also grow symmetrically on the top/bottom surface of the ZnS nanobelts. The optical property of the products was also recorded by means of photoluminescence (PL) spectroscopy.     

ZnO nanorod arrays grown on glass substrates below glass transition temperature by metalorganic chemical vapor deposition

High density, well-aligned ZnO nanorods with uniform distributions in their diameters and lengths are successfully prepared on amorphous substrates by metalorganic chemical vapor deposition. The X-ray diffraction measurements indicate that the ZnO nanorods are of wurtzite crystal structure, and are grown preferentially on glass substrates along the [0001]_ZnO direction. The degree of the preferred orientation of the ZnO nanorods is enhanced by increasing the growth temperature, as confirmed by the X-ray diffraction and selected area electron diffraction patterns. Photoluminescence investigations revealed the enhancement of the band edge emission with increasing growth temperature, suggesting the improvement in the optical quality of the ZnO nanorods with increasing temperature.     

Epitaxial growth of ZnO layers using nanorods with high crystalline quality

Epitaxial ZnO films were grown on c-plane sapphire substrates by metal-organic chemical vapor deposition using a ZnO multi-dimensional structure having the sequence of ZnO film/ZnO nanorods/sapphire. The vertically well-aligned one-dimensional ZnO nanorods were grown epitaxially on the sapphire substrate with in-plane alignment under suitable growth conditions and then used as seeds for the subsequent epitaxial ZnO layer. For the transition of the ZnO structures from the nanorods to the film, the growth temperature and working pressure were controlled, while keeping the other conditions fixed. The growth of the ZnO films on the well-aligned ZnO nanorods results in homoepitaxial growth with the identical orientation relationship along the in-plane direction as well as the same c-axis orientation. The microstructural analysis of the multi-dimensional structure and analysis of the microstructural evolution from the one-dimensional nanorods to the two-dimensional film were conducted using transmission electron microscopy.     

Charge influence and growth mechanism of ZnO nanorods

We demonstrate the influence of charges near the substrate surface on vertically aligned ZnO nanorod growth. ZnO nanorods were fabricated on n-type GaN with and without H+ treatments by catalyst-free metal-organic chemical vapor deposition. The ZnO nanorods grown on n-GaN films were vertically well-aligned and had a well-ordered wurtzite structure. However, the ZnO did not form into nanorods and the crystal quality was very degraded as they were deposited on the H+ treated n-GaN films. The charge influence was also observed in the ZnO nanorod growth on sapphire substrates. These results implied that the charges near the substrate surface dominantly affected on the crystalization and formation of ZnO nanorods.     

Silver nanoisland induced synthesis of ZnO nanostructures by vapor phase transport

ZnO nanostructures including nanorod and nanotower were synthesized on Ag nanoisland coated Si substrate by thermal evaporation and vapor phase transport at atmospheric pressure. The as-prepared ZnO nanorods and nanotowers were single crystal growing along [0001] direction. The growth of ZnO nanostructures strongly depended on the surface morphology of the nanoisland Ag film deposited by electroless nanoelectrochemistry. The growth mechanism of the ZnO nanostructures was proposed on the basis of experimental data. A strong room-temperature photoluminescence in ZnO nanostructures has been demonstrated. The growth technique would be of particular interest for direct integration in the current silicon-technology-based optoelectronic devices.