ZnO纳米阵列增强大功率蓝光LED出光效率的研究

采用低成本的化学溶液法在大功率GaN基蓝光LED芯片上生长ZnO纳米阵列, 以提高LED芯片的出光效率. 通过改变生长溶液中氨水及锌离子浓度实现对纳米阵列结构形貌的可控性, 进而得到不同形貌的ZnO纳米阵列. 在此基础上, 进一步研究纳米结构形貌对LED芯片出光性能的影响, 探讨纳米结构增强LED芯片发光效率的机理. 结果表明, 较高密度、锥形形貌的ZnO纳米阵列更有利于增强LED芯片的出光效率. 在优化的实验条件下, 表面沉积ZnO纳米阵列的LED芯片比普通LED的出光效率高出60%以上, 并且纳米阵列不影响LED器件的电学性能和发光稳定性.     

低温水热法生长ZnO纳米棒阵列的电子结构及光学特性(英文)

使用低温水热法在Si衬底上生长ZnO纳米棒阵列.通过X射线衍射和扫描电子显微镜对ZnO纳米棒的结晶性和形貌进行观测.结果表明,六棱柱形ZnO纳米棒沿c轴方向的阵列性良好,且均匀致密的生长在衬底上.室温光致发光谱表明应用低温水热法可以得到光学性质良好的ZnO纳米棒阵列.使用同步辐射对ZnO纳米棒阵列的氧K带边进行X射线吸收近带边谱测量,研究了不同半径ZnO纳米棒阵列的局部电子结构及其半径对电子结构的影响.另外,对ZnO纳米棒及ZnO薄膜的局部电子结构进行了对比研究.     

准一维纳米结构ZnO的制备研究进展

准一维纳米结构ZnO因其优良的光电性质,在制作纳米电子器件和纳米光电子器件等许多领域表现出巨大的应用潜力.对准一维纳米结构ZnO在衬底上的制备生长方法、性质及衬底的影响作了简要的叙述.     

不同衬底上氧化锌纳米结构的水热法制备研究

采用水热方法,以氯化锌和氨水为反应溶液,在铜和硅等不同基底上制备出不同特征的ZnO纳米棒和纳米管阵列.借助SEM和xRD等手段对其结构和形貌进行了分析研究.在常温下该样品表现出很好的光致发光性能.实验表明,在水热法中ZnO纳米材料的形貌、取向、排列等特征与衬底的选择有直接的关系.通过分析ZnO纳米管的形成过程,提出了一种新的由ZnO纳米棒在低温下溶解制得ZnO纳米管的生长机理.     

花状ZnO超细结构的水热自组装

通过简单的水热合成路线,合成出由ZnO纳米棒束组装的花状结构.其组成结构单元ZnO纳米棒沿［001］晶向生长,呈很好的单晶结构.大部分纳米棒直径约为500nm,长约6.0μm.研究结果表明,在无水乙二胺存在的条件下,氨水（28%, v/v）在ZnO花状结构的形成过程中起到了至关重要的作用.调节氨水的含量,组成结构单元ZnO纳米棒可以组装成不同的花状结构.当加入氨水的量使得溶液的pH值达到10时,即可得到由ZnO纳米棒束组装成的花状结构,并简单讨论了这种花状结构的形状结构的形成机理.      

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。     

水热法制备不同形貌的氧化锌纳米结构

采用水热法,用甲酰胺水溶液和锌片建立反应体系,在不同种晶层上制备出不同形貌的ZnO纳米结构,所用基底有Si片、镀有ZnO薄膜的Si片、镀有ITO薄膜的Si片、涂有ZnO粉末的Si片等,研究了不同的种晶层对ZnO纳米结构的形貌的影响。在不同温度下,分别在镀有ZnO薄膜和ITO薄膜的医用载玻片衬底上生长ZnO纳米结构,研究了温度在水热法中的作用及种晶层对纳米杆长度的影响。实验中用扫描电子显微镜（SEM）和X射线衍射仪（XRD）对纳米聚集体进行了表征。SEM表征结果表明不同种晶层上获得的ZnO纳米结构形貌差异很大;反应时间、甲酰胺水溶液浓度以及反应温度对ZnO纳米阵列形貌都有着一定的影响;在ZnO薄膜上生长的纳米杆较在ITO薄膜上生长的纳米杆长。SEM图像同时表明氧化锌纳米杆随着温度的增大,纳米杆的长度和杆径增大。X射线衍射峰在34.6℃有很强的（002）纤锌矿衍射峰,该峰表明衬底上有高度c轴取向的大面积纳米杆阵列和较好的结晶质量。     

ZnO纳米结构的CVD制备工艺及其应用

纳米结构的ZnO由于具有优异的光、电、磁、声等性能,已经成为光电、化学、催化、压电等领域中聚焦的研究热点之一.不同纳米结构的ZnO其制备方法不同,着重概述了采用化学气相沉积(CVD)工艺制备ZnO纳米材料,包括直接热分解、高温加热锌粉、碳热还原法以及金属有机气相沉积(MOCVD)4种方法,重点讨论了不同锌源和氧源对ZnO纳米结构的影响规律,并初步探讨了ZnO的VLS与VS生长机理,同时展望了ZnO在各领域中的最新应用.     

Studies of ZnO Nanostructures Synthesized by CVD and Its Applications

纳米结构的ZnO由于具有优异的光、电、磁、声等性能,已经成为光电、化学、催化、压电等领域中聚焦的研究热点之一.不同纳米结构的ZnO其制备方法不同,着重概述了采用化学气相沉积(CVD)工艺制备ZnO纳米材料,包括直接热分解、高温加热锌粉、碳热还原法以及金属有机气相沉积(MOCVD)4种方法,重点讨论了不同锌源和氧源对ZnO纳米结构的影响规律,并初步探讨了ZnO的VLS与VS生长机理,同时展望了ZnO在各领域中的最新应用.     

气相生长纳米碳纤维的形态控制

报道了在浮动催化系统中,催化剂、促进剂以及苯/氢气比例等因素对气相生长纳米碳纤维形态的决定性作用和不同结构形态纳米碳纤维的选择生长.利用控制催化剂前体和促进剂的含量以及苯与氢气的比例等因素,制备了平直碳纳米管、弯曲碳纳米管、碳珠/纳米碳纤维、纳米碳纤维等不同结构的气相生长纳米碳纤维.实验结果表明,在浮动催化系统中,调节催化剂和促进剂的含量以及苯与氢气的摩尔比等关键性因素可以实现对气相生长纳米碳纤维形态结构的控制.     

Hydrothermal growth of ZnO nanostructures

One-dimensional nanostructures exhibit interesting electronic and optical properties due to their low dimensionality leading to quantum confinement effects. ZnO has received lot of attention as a nanostructured material because of unique properties rendering it suitable for various applications. Amongst the different methods of synthesis of ZnO nanostructures, the hydrothermal method is attractive for its simplicity and environment friendly conditions. This review summarizes the conditions leading to the growth of different ZnO nanostructures using hydrothermal technique. Doping of ZnO nanostructures through hydrothermal method are also highlighted.     

Hydrothermal growth of ZnO nanostructures

Abstract

One-dimensional nanostructures exhibit interesting electronic and optical properties due to their low dimensionality leading to quantum confinement effects. ZnO has received lot of attention as a nanostructured material because of unique properties rendering it suitable for various applications. Amongst the different methods of synthesis of ZnO nanostructures, the hydrothermal method is attractive for its simplicity and environment friendly conditions. This review summarizes the conditions leading to the growth of different ZnO nanostructures using hydrothermal technique. Doping of ZnO nanostructures through hydrothermal method are also highlighted.     

Heterogeneous graphene nanostructures: ZnO nanostructures grown on large-area graphene layers

In this work, the synthesis and characterization of three-dimensional hetergeneous graphene nanostructures (HGN) comprising continuous large-area graphene layers and ZnO nanostructures, fabricated via chemical vapor deposition, are reported. Characterization of large-area HGN demonstrates that it consists of 1-5 layers of graphene, and exhibits high optical transmittance and enhanced electrical conductivity. Electron microscopy investigation of the three-dimensional heterostructures shows that the morphology of ZnO nanostructures is highly dependent on the growth temperature. It is observed that ordered crystalline ZnO nanostructures are preferably grown along the <0001> direction. Ultraviolet spectroscopy and photoluminescence spectroscopy indicates that the CVD-grown HGN layers has excellent optical properties. A combination of electrical and optical properties of graphene and ZnO building blocks in ZnO-based HGN provides unique characteristics for opportunities in future optoelectronic devices.     

ZnO纳米结构的CVD制备工艺及其应用

纳米结构的ZnO由于具有优异的光、电、磁、声等性能,已经成为光电、化学、催化、压电等领域中聚焦的研究热点之一.不同纳米结构的ZnO其制备方法不同,着重概述了采用化学气相沉积(CVD)工艺制备ZnO纳米材料,包括直接热分解、高温加热锌粉、碳热还原法以及金属有机气相沉积(MOCVD)4种方法,重点讨论了不同锌源和氧源对ZnO纳米结构的影响规律,并初步探讨了ZnO的VLS与VS生长机理,同时展望了ZnO在各领域中的最新应用.     

Growth and optical properties of ZnO low-dimensional nanostructures

Recent studies on the growth of ZnO nanostructures and their optical properties were reviewed. Using different methods, a variety of ZnO nanostructures, including quantum dots nanotowers, nanotubes, nanorods, nanowires, and nanosheets, displaying zero, one, and two dimensions, have been synthesized. The growth of ZnO low-dimensional nanostructures has been demonstrated. Their optical properties have been studied by means of room-temperature photoluminescence spectra, low-temperature photoluminescence spectra, temperature-dependent photoluminescence spectra, and pressure-dependent photoluminescence spectra. The optical properties can be adjusted by the surface features of ZnO low-dimensional nanostructures. The strong exciton emission has been observed in some nanostructures, showing promising potential in nanodevice applications.     

One-dimensional ZnO nanostructures: fabrication, optoelectronic properties, and device applications

One-dimensional (1D) zinc oxide (ZnO) nanostructures have been extensively and intensively studied for several decades not only for their extraordinary chemical and physical properties, but also for their current and future different electronic and optoelectronic device applications. This review provides a brief overview of the progress of different synthesis methods and applications of 1D-ZnO nanostructures. Morphology of ZnO nanostructures grown by various methods and progress in the optical properties are briefly described. Using low-temperature photoluminescence (LTPL) study, detailed informations about the defect states and impurity of such nanostructures are reported. Improvement of field emission properties by modifying the edge of 1D-ZnO nanostructures is briefly discussed. Applications such as different sensors, field effect transistor, light-emitting diodes (LEDs), and photodetector are briefly reviewed. ZnO has large exciton binding energy (60 meV) and wide band gap (3.37 eV), which could lead to lasing action based on exciton recombination. As semiconductor devices are being aggressively scaled down, ZnO 1D nanostructures based resistive switching (RS) memory (resistance random access memory) is very attractive for nonvolatile memory applications. Switching properties and mechanisms of Ga-doped and undoped ZnO nanorods/NWs are briefly discussed. The present paper reviews the recent activities of the growth and applications of various 1D-ZnO nanostructures for sensor, LED, photodetector, laser, and RS memory devices.     

Effect of microwave power on the morphology and optical property of zinc oxide nano-structures prepared via a microwave-assisted aqueous solution method

The effect of the microwave power on the morphology and optical properties of zinc oxide nanostructures prepared using a microwave-assisted aqueous solution method has been investigated. The ZnO nanostructures were synthesized from zinc chloride and sodium hydroxide mixed aqueous solutions exposed for 5 min to microwave radiation at four different powers, namely 150, 450, 700 and 1000 W. The morphologies of the samples have been characterized by transmission electron microscope (TEM) and scanning electron microscope (SEM). The results showed that the power of microwave radiation influenced the shape and size of the synthesized nanostructures. It is also found that the average particle size of nanostructures decreased with decreasing microwave power. The results of X-ray diffraction (XRD) showed that all the as-prepared ZnO nanostructures are in crystalline form with high purity. The infrared (IR) spectra indicated that the as-prepared nano ZnO product can be used as infrared gas sensors such as an infrared carbon dioxide (CO₂) and/or CO sensor. Optical properties of the as-prepared ZnO nanostructures were investigated by UV–vis spectroscopy and showed that the optical properties of as-synthesized ZnO samples are sensitive to the variation of the power of microwave radiation.     

Zinc oxide nanostructures: from growth to application

Zinc oxide’s (ZnO) physical and chemical properties make it a viable and extremely attractive compound to use in a variety of nanotechnology applications. Some of these applications include biomedical, energy, sensors, and optics. As the research in ZnO nanostructures continue to grow, it has inspired a whole host of new innovative applications. Complementing its unique chemical qualities, it also has a simple crystal-growth technology and offers significantly lower fabrication costs when compared to other semiconductors used in nanotechnology. Several processes have been developed in order to synthesize high quality ZnO nanostructures—specifically in the case of nanowires. Here we offer a comprehensive review on the growth methods currently employed in research, industry, and academia to understand what protocols are available to meet specific needs in nanotechnology. Methods examined include: the vapor–liquid–solid, physical vapor deposition, chemical vapor deposition, metal–organic chemical vapor deposition, and the hydrothermal-based chemical approach. Each of these methods is discussed and their strengths and weaknesses are analyzed with objective comparison metrics. In addition, we study the current state-of-the-art applications employing ZnO nanostructures at their core. A historical perspective on the evolution of the field and the accompanying literature are also presented.     

一维ZnO纳米结构的场发射研究进展

一维纳米结构材料因其优异的电、光及场发射特性，在光电器件、场发射器件等方面具有重要的应用价值而备受关注。ZnO因具有优异的化学及热稳定性，并且其一维纳米结构具有极大的场增强因子，因而在场发射器件阴极中有良好的应用前景。首先简要介绍了ZnO的结构与性质，并重点介绍了ZnO一维纳米材料的常用制备技术及其在场发射领域的研究进展。     

The Interplay of Growth Mechanism and Properties of ZnO Nanostructures for Different Applications (Small 44/2023)

This review provides a background on the structure and properties of ZnO nanostructures. ZnO nanostructures are advantageous for many applications in sensing, photocatalysis, functional textiles, and cosmetic industries, which are described in this review. Previous work using UV Visible (UV–vis) spectroscopy and scanning electron microscopy (SEM) for ZnO nanorod growth analysis in-solution and on a substrate for determination of optical properties and morphology is discussed, as well as their results in determining the kinetics and growth mechanisms. From this literature review, it is understood that the synthesis process greatly affects nanostructures and properties; and hence, their applications. In addition, in this review, the mechanism of ZnO nanostructure growth is unveiled, and it is shown that by having greater control over their morphology and size through such mechanistic understanding, the above-mentioned applications can be affected. The contradictions and gaps in knowledge are summarized in order to highlight the variations in results, followed by suggestions for how to answer these gaps and future outlooks for ZnO nanostructure research.