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纳米小论文ZnO纳米半导体材料制备

纳米小论文ZnO纳米半导体材料制备

ZnO纳米半导体材料制备ZnO纳米半导体材料制备摘要:纳米微粒的粒径一般在 1~100nm,具有粒子尺寸小、比表面积大、表面原子数多、表面能和表面张力随粒径的下降急剧增大等特点,其组成的材料具有量子尺寸效应、表面效应、体积效应和宏观量子隧道效应,不同寻常的电学、磁学、光学和化学活性等特性,已在化工、制药、微电子、环境、能源、材料、军事、医学等领域展示了广泛的应用前景。

文章阐述了一些制备ZnO纳米半导体材料的常用技术,如模板制备法、物理气相沉积、脉冲激光沉积、分子束外延、金属有机化合物气相沉积等。

关键词:ZnO 制备纳米材料方法ZnO是一种新型的宽禁带半导体氧化物材料,室温下能带宽度为3.37eV,略低于GaN的3.39eV,其激子束缚能(60meV)远大于GaN(25meV)的激子束缚能。

由于纳米ZnO在紫外波段有较强的激子跃迁发光特性,所以在短波长光子学器件领域有较广的应用前景。

此外,ZnO纳米半导体材料还可沉积在除Si以外的多种衬底上,如玻璃、Al2O3、GaAs等,并在0.4-2μm的波长范围内透明,对器件相关电路的单片集成有很大帮助,在光电集成器件中具有很大的潜力。

本文阐述了近年来ZnO纳米半导体材料的制备技术。

ZnO是一种应用较广的半导体材料,在很多光学器件和电学器件中有很广泛的应用,由此也产生了多种纳米半导体器件的制备方法,主要有以下几种:1模板制备法模板制备法是一种用化学方法进行纳米材料制备的方法,被广泛地用来合成各种各样的纳米棒、纳米线、纳米管等。

此种方法使分散的纳米粒子在已做好的纳米模板中成核和生长,因此,纳米模板的尺寸和形状决定了纳米产物的外部特征。

科学家们已经利用孔径为40nm 和20nm左右的多孔氧化铝模板得到了高度有序的ZnO纳米线。

郑华均等人用电化学阳极氧化-化学溶蚀技术制备出了一种新型铝基纳米点阵模板,此模板由无数纳米凹点和凸点构成,并在此模板上沉积出ZnO纳米薄膜。

半导体纳米材料范文

半导体纳米材料范文

半导体纳米材料范文半导体纳米材料是一类具有特殊尺度效应的材料,其尺寸通常在1到100纳米之间。

由于其纳米尺寸,使得半导体纳米材料的电学、光学和磁学性质与其宏观对应物质存在较大的差异,具有许多独特的优势和应用前景。

以下是关于半导体纳米材料的一些重要内容。

首先,半导体纳米材料具有量子尺寸效应。

量子尺寸效应是指当半导体材料的尺寸缩小到纳米级别时,电子和空穴受限于内部空间,其运动仅限于三个维度之内,从而产生量子化的能级结构。

这种量子化的能级结构会影响材料的光学、电学和磁学性质,导致具有特殊的光学吸收、荧光发射性质等。

半导体纳米材料还具有高度可调性。

随着纳米颗粒的尺寸变化,半导体纳米材料的能带结构和带隙能随之改变。

这种可调性使得半导体纳米材料能够在可见光和红外光谱范围内表现出不同的光学吸收和发射性质,从而广泛应用于传感器、太阳能电池等领域。

此外,半导体纳米材料还具有高比表面积和界面效应。

由于其纳米尺寸,半导体纳米材料具有非常高的比表面积,使其能够提供更多的反应位点,从而增强了其在催化剂、储能材料等方面的应用潜力。

此外,纳米材料的界面效应也会对其光学和电学性质产生影响,从而进一步拓宽了其应用范围。

半导体纳米材料在能源领域具有广泛的应用前景。

例如,半导体纳米材料可以应用于太阳能电池中,以提高光电转化效率。

由于其量子尺寸效应和可调性,半导体纳米材料能够对太阳光谱的不同波长具有选择性地吸收和发射,从而实现更高效的光电转化。

此外,在储能材料方面,半导体纳米材料还可以用于锂离子电池、超级电容器等领域,以提高储能密度和循环稳定性。

此外,半导体纳米材料还具有许多其他应用。

例如,在生物医学领域,半导体纳米材料可以用于生物标记、癌症治疗等应用,通过调控其光学性质和表面功能化,实现对细胞和组织的高灵敏检测和精确治疗。

在光电子学领域,半导体纳米材料也可以用于光学器件和显示技术,如LED、激光器等。

总之,半导体纳米材料的独特性质使其在能源、生物医学、光电子学等领域具有广泛的应用前景。

半导体纳米材料的表面增强拉曼光谱研究

半导体纳米材料的表面增强拉曼光谱研究

半导体纳米材料的表面增强拉曼光谱研究半导体纳米材料是一种在当今科技领域中备受关注的研究对象。

它具有很多优点,如小体积、高表面积、良好的光电性能等。

随着科技的发展,半导体纳米材料的研究和应用正呈现出越来越广泛的前景。

在半导体纳米材料的研究中,表面增强拉曼光谱技术是一种非常重要的手段。

本文将从表面增强拉曼光谱技术的原理、半导体纳米材料的应用以及未来发展方向等方面进行探讨。

一、表面增强拉曼光谱技术的原理表面增强拉曼光谱技术是将待测样品放置于金属表面上,通过金属表面的局域化表面等离子体共振现象,增强样品的拉曼信号。

表面增强拉曼光谱技术主要是基于两个原理,即电磁增强与化学增强。

在电磁增强机制中,金属表面的等离子体振荡与光子的激发相结合,导致高强度的电磁场在金属表面的纳米孔隙中形成,使待测样品的拉曼信号得到增强。

而化学增强机制则是通过金属表面上的活性位点与待测样品之间的化学反应,从而实现信号的增强。

二、半导体纳米材料的应用半导体纳米材料的表面增强拉曼光谱技术有着广泛的应用前景。

首先,它可以用于表征半导体纳米材料的结构、形貌、成分以及表面活性位点等信息。

其次,表面增强拉曼光谱技术还可以用于探索半导体纳米材料的光谱响应和表面性质等。

例如,在太阳能电池等能源领域,半导体纳米材料的表面增强拉曼光谱技术可以用于表征太阳能电池中的光敏剂的结构和形貌,进而探究太阳能电池的性能。

此外,在生物医学领域中,半导体纳米材料的表面增强拉曼光谱技术也被应用于生命分析、疾病诊断等方面。

三、半导体纳米材料表面增强拉曼光谱技术的未来发展方向表面增强拉曼光谱技术作为一种非常重要的超分辨率光谱技术,其应用前景非常广泛。

在半导体纳米材料的表面增强拉曼光谱技术的研究方面,随着技术的不断发展,未来存在着以下几个方向的发展。

首先,随着光学技术和信号处理技术的发展,表面增强拉曼光谱技术的探测极限将会进一步提高。

其次,未来表面增强拉曼光谱技术将更加注重在金属纳米结构、活性位点等方面的设计和优化,以提高拉曼信号的增强度和可重现性。

纳米技术与芯片作文200字

纳米技术与芯片作文200字

纳米技术与芯片作文200字英文回答:Nanotechnology and the ongoing development ofmicrochips are two of the most exciting and rapidly advancing fields of science and technology today. Nanotechnology is the study of manipulating matter at the atomic and molecular scale, and it has the potential to revolutionize a wide range of industries, including electronics, healthcare, and manufacturing. Microchips, on the other hand, are tiny electronic circuits that are usedin a variety of devices, from computers to smartphones. The combination of nanotechnology and microchips has the potential to create new and innovative devices that are smaller, more powerful, and more efficient than ever before.One of the most promising applications of nanotechnology in the microchip industry is the development of new materials that can be used to create smaller and faster transistors. Transistors are the basic buildingblocks of microchips, and they control the flow of electricity through the circuit. By using nanotechnology to create new materials with improved electrical properties, it is possible to create transistors that are smaller, faster, and more energy-efficient. This could lead to the development of new microchips that are capable of performing more complex tasks at a lower cost.Another potential application of nanotechnology in the microchip industry is the development of new ways to connect transistors together. Currently, transistors are connected together using metal wires, which can be a bottleneck for the flow of electricity. By using nanotechnology to create new materials that can be used to connect transistors together, it is possible to create microchips that are more efficient and have a higher performance.The combination of nanotechnology and microchips has the potential to revolutionize the electronics industry. By creating new materials and new ways to connect transistors together, it is possible to create microchips that aresmaller, faster, and more efficient than ever before. This could lead to the development of new electronic devicesthat are more powerful, more portable, and more affordable.中文回答:纳米技术和芯片的持续发展是当今科学技术领域最令人激动和快速进步的领域之一。

半导体纳米材料中的能带结构研究

半导体纳米材料中的能带结构研究

半导体纳米材料中的能带结构研究在半导体纳米材料中的能带结构研究中,科学家们通过对材料的电子结构进行探索,为新一代纳米电子器件的研发提供了重要的理论基础。

半导体纳米材料具有优异的电子传输性能和特殊的能带结构,使其在纳米电子学领域具有广泛的应用前景。

能带结构是半导体材料的重要性质,它决定了半导体材料的导电性质和光电特性。

通过对能带结构的研究,科学家能够深入了解半导体纳米材料的基本电子性质,并为其电子结构调控和性能优化提供指导。

半导体纳米材料的能带结构是由其晶体结构和材料成分所决定的。

在纳米尺度下,晶格常数和晶胞结构发生变化,使得材料的能带结构与宏观晶体有很大差异。

此外,半导体纳米材料通常由不同元素的异质结构组成,这使得其能带结构更加复杂多样。

因此,科学家们需要运用先进的实验技术和理论模拟方法,来研究和理解半导体纳米材料的能带结构。

近年来,借助于高分辨率的电子能谱技术,科学家们已经能够在纳米尺度下直接观测和研究半导体纳米材料的能带结构。

例如,通过扫描隧道显微镜技术,科学家们可以实时观察纳米材料的能带结构,从而对其电子行为进行定量研究。

此外,还可以利用透射电子显微镜和原子力显微镜等手段,对纳米材料进行结构表征和成分分析。

这些实验技术的发展为半导体纳米材料的能带结构研究提供了强大的工具。

除了实验方法,理论模拟也是研究半导体纳米材料能带结构的重要手段。

基于量子力学的理论模拟方法,如密度泛函理论和紧束缚模型等,已经被广泛应用于半导体纳米材料的能带结构计算。

这些方法通过求解薛定谔方程,可以得到材料的电子能级和能带分布。

同时,理论模拟还能够模拟和预测材料的光电性质,为光电器件的设计和优化提供理论指导。

通过实验和理论的相互验证和补充,科学家们已经在半导体纳米材料的能带结构研究中取得了重要进展。

以硅纳米材料为例,通过实验观测和理论模拟,科学家们发现硅纳米材料的能带结构具有量子尺寸效应和表面束缚能级的特点。

这些特点不仅影响着硅纳米材料的导电性质,还使其具有优异的光电响应和能级调控能力。

半导体材料以及材料表征论文-GrowthofSiCNanorodsonSiSubstrate

半导体材料以及材料表征论文-GrowthofSiCNanorodsonSiSubstrate

Growth of SiC Nanorods on Si SubstrateAbstractSilicon carbide (SiC) is a ™-™ compound semiconductor material with a wide band gap. Semiconductor electronic devices and circuits made from SiC are presently being developed for high-temperature, high-power, and high-radiation conditions in which conventional semiconductors cannot adequately perform. One-dimensional SiC, such as nanowires and nanorods, is of great interests for many applications due to their excellent properties, such as high mechanical strength, high thermal stability, high thermal conductivity. Especially SiC nanorods are widely considered as reinforcement materials for ceramic composites providing very high strength and toughness due to their very high elastic modulus and strength over their bulk-counterpart. In this study, the SiC nanorods were fabricated by vapor-liquid-solid (VLS) mechanism on Si substrate. The SiC nanaorods were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD)and energy diffraction spectrometer (EDS).The factors which influenced the formation of SiC nanorods were studied.Keywords: SiC nanorods, VLS mechanism, CVDIntroductionSilicon carbide (SiC) is a wide band gap semiconductor with many super properties, such as high breakdown field,high thermal conductivity, high saturation drift velocity, low relative dielectric constant and excellent resistance to oxidation and corrosion[1-2]. These outstanding properties make SiC a very attractive semiconductor material. For example, SiC is commercially applied for optoelectronic devices [3], such as photodiodes and light-emitting diodes which emit throughout the visible spectrum into the ultraviolet. The applications of SiC also cover the area of high-temperature sensors, high-power devices, and microwave devices (both avalanche diodes and field effect transistors).In the meantime, since carbon nanotubes emerged into the scientific world in 1991 and their exceptional excellent properties were introduced, one-dimensional nanomaterials such as SiC, GaN, have attracted much interest from researchers because the extreme geometry of the nanomaterials is of importance to investigate the physical and chemical properties of the materials such as their quantum size effect. These nanosized materials are important for ceramic nanocomposite materials [4, 5]. They are also claimed to be promising raw materials for engineering ceramic devices offering superplasticity and high strength at high temperatures. Furthermore nanoscale filters or support for a catalytic surface might be interesting application of SiC nanopowders.A lot of methods have been developed to synthesize SiC nanorods [6]. SiC nanorods can be fabricated without the metallic catalysts. For instance, Zhou [7] fabricated SiC nanowires by the hot filament chemical vapor deposition (CVD) method. B.-C. Kang synthesized SiC nanorods by CVD method.Li [8] synthesized SiC nanowires by using a SiC rod as the anode to arc-discharge. And Hyung Suk Ahn [9] synthesized SiC nanorods by using LPCVD. SiC nanorods can be also fabricated with the metallic catalysts. For example, B.-C. Kang fabricated SiC nanorods by using nickel as a catalyst. And Zhang [10] et al. synthesized SiC nanorods using Fe powders as the catalyst. Among these methods, carbothermal reduction of silica-containing materials and the CVD method are the most commonly employed.In carbonthermal reduction process, three mechanisms are involved to form SiC nanorods. They are called vapor-solid (VS) mechanism, two-stage growth (TS) mechanism and vapor-liquid-solid (VLS) mechanism. [11] By the VS mechanism, the nanorods are grown by direct accommodation of silicon and carbon atoms to the growth plane from the silicon- and carbon-carrying vapors. The nanorods are formed in the raw materials containing metal impurities such as rice-hulls by the TS mechanism. The impurities form discrete liquid droplets on the growth plane. The droplets are quickly covered with vapor species because of their high accommodation coefficient and act as nucleation sites for thenanorods growth. It results in axial growth of nanaorods (first stage), and, then in lateral thickening (second stage) [11, 12]. The essential features of VLS mechanism can be expressed as the growth of nanorods via the assistance of liquid solution containing the desired ingredient of the nanorods to be grown. The processes are complex and the fundamental issues remain to be ascertained. The growth of nanorods involves the dissolution of solute at the vapor/liquid interface and its subsequent precipitate at the liquid/solid interface during the VLS growth process. In this paper, nickel was used as a metallic catalyst to deposit SiC nanorods on Si substrate via the VLS mechanism.ExperimentSiC nanorods were fabricated in metalorganic chemical vapor deposition (MOCVD) system. The water-cooled reactor, as shown inFig. 1 schematic configuration of MOCVD reactorFig.1, was a horizontal quartz tube. First, nickel thin film with thickness of 400∗500 nm, which acted as a catalyst in growing SiC nanorods, was deposited on Si substrate by DC sputtering. The Si substrates covered with nickel thin flim were set on a SiC-coated graphite susceptor, which was heated by ratio frequency (RF) induction. According to Ni-Si and Ni-C phasediagram [13-15], the growth temperature was selected between 1250ε and 1380ε . Silane (SiH4) and acetylene (C2H2) were used as source gas. Hydrogen (H2) gas purified by a Pd purifier was used as the carrier gas. The flow rate of H2 was fixed to be 500 sccm (standard cubic centimeter per minute). And the growth pressure of SiC nanorods was fixed to be 60 Torr.Two processes were carried out to synthesize SiC nanorods. One was called two-step process, in which only C2H2 was first introduced into the reactor to fabricate carbon nanotubes on the Si substrates covered nickel thin film at 1150ε for several minutes. Then the growth temperature increased to 1150ε∗1350ε , and C2H2 and SiH4 were reacted as the source gas to synthesize SiC nanorods. Another process was called one-step process, in which C2H2 and SiH4 as the source gases were introduced into the reactor at the same time.The crystal structure of SiC nanorods was characterized by X-ray diffraction (XRD). The morphology of SiC nanorods was characterized by scanning electron microscopy (SEM). Energy dispersive spectrometer(EDS) was carried out to identify their chemical composition.Results and discussion1.SiC nanorods synthesized by two-step processBy the two-step process, carbon nanotubes were first synthesized on the Si substrate in the carbonized process. The morphology and the composition characterized by SEM and EDS, were shown in Fig.2 and Fig.3 respectly. The Ag peak appeared in the EDS image was introduced in the experiment during the SEM and EDS analysis. According to the figure, high density of carbon nanotubes was grown on the Si substrate.Fig. 2 SEM images of carbon naotubes grown on a Si substrateFig. 3 EDS spectrum of carbon nanotubesgrown on a Si substrateThe XRD spectrum of SiC nanorods synthesized by two-step process was shown in Fig.4. In the XRD patterns, characteristic peaks from (111), (200) and (220) plane of ß-SiC appeared at 35.68°, 47.68° and 60.16°, respectively. Peaks from other polytypes of SiC were not observed, so the SiC nanorods were zinc-blende structure.The morphology of SiC nanorods was depicted in Fig.5. High density of nanorods was randomly grown on the substrate. The diameters of SiC nanorods were almost the same.2. SiC nanorods synthesized by one-step processThe characters of the SiC nanorods fabricated by one-step process were characterized by XRD, SEM and EDS. The results are shown in Fig.6∗8 and table 1. In general, SiC nanorods were synthesized by one-step process.Fig. 4 XRD patterns of SiC nanorods Fig. 5 SEM image of SiC nanorodssynthesized by two-step methodAlthough all the samples were growth by VLS mechanism, it was clearly that the diameter of the SiC nanorods fabricated by one-step process was much larger than that prepared by two-step process. The reasons should be the confinement effect of carbon nanotubes in two-step process. The size of carbon nanotubs limited the lateral growth of SiC nanorods and led to the diameter of SiC nanorods almost the same as that of carbon nanotubes. For the one-step process, however the main factors which determined the diameter of SiC nanorods should be the volume of liquid droplet and wetting behavior [16-17], so the diameter of SiC nanorods, Fig. 7 SEM image of SiC nanorodsfabricated by one-step process Fig. 6 XRD pattern of SiC nanorods fabricatedby one-step process Fig.8 EDS spectrum of SiC nanorods by one-step processwas much larger.The atomic content of carbon was higher than that of silicon for the SiC nanorods made by one-step process as shown in table 1. It should be originate from the result of C2H2 activity. Because of its high activity, C2H2 should be decomposed very quickly at 1250ε . A lot of carbon atoms deposited on Si substrate. However, not enough silicon atoms reacted with them. So the redundant carbon atoms formed amorphous carbon on the substrate.SummarySiC nanorods were successfully synthesized via VLS mechanism by two-step process and one-step process. The structure, morphology and composition were characterized by XRD, SEM and EDS. Factors which affected the diameter of SiC nanorods were discussed.References[1].Philip G. Neudeck, SiC technology (1998).[2].Philip G. Neudeck, High-temperature electronics –a role for wide bandgapsemiconductors, Proceedings of the IEEE, Vol 90, No 6 (2004).[3].Han-Kyu Seong, Heon-Jin Choi and Sang-Kwon Lee, Optical and electricaltransport properties in silicon carbide nanowires, Applied Physics Letters, Vol 85,No 7 (2004).[4].B.-C. Kang*, S.-B. Lee, J.-H. Boo*, Growth of ß -SiC nanowires on Si(100)substrates by MOCVD using nickel as a catalyst, Thin Solid Films 464–465 (2004) 215– 219[5].Heon-Jin Choia,*, Han-Kyu Seonga, Jung-Chul Leeb, Yun-Mo Sungb, Growthand modulation of silicon carbide nanowires, Journal of Crystal Growth 269 (2004) 472–478[6].Qingyi Lu, Junqing Hu, Kaibin Tang,a) and Yitai Qian, Growth of SiC nanorodsat low temperature, Appl. Phys. Lett VOL 75, No 4,[7].X.T. Zhou, N. Wang, H.L. Lai, H.Y. Peng, I. Bello, N.B. Wang, C.S. Lee, S.T.Lee, Appl. Phys. Lett. 74 (1999) 3942.[8].Y.B. Li, S.S. Xie, X.P. Zou, D.S. Tang, Z.Q. Liu, W.Y. Zhou, G.Wang, J. Cryst.Growth 223 (2001) 125.[9].Hyung Suk Ahn, Doo Jin Choi, Fabrication of silicon carbide whiskers andwhisker-containing composite coatings without using a metallic catalyst, Surface and Coatings Technology 154 (2002) 276-281.[10].Y ingjun Zhang, Nanlin Wang et al, synthesis of SiC nanorods using floatingcatalyst, Solid state communications 118(2001)595-598[11].H eon-Jin Choi *, June-Gunn Lee, Stacking faults in silicon carbide whiskers,Ceramics International 26 (2000) 7-12[12].R.S. Wagner, W.C. Ellis, Appl. Phys. Lett. 4 (5) (1964) 89.[13].C. Rado, et al, wetting and bonding of Ni±Si alloys on Silicon, Acta mater. Vol.47, No. 2, pp. 461-473, 1999[14].J. Acker*, K. Bohmhammel, Optimization of thermodynamic data of the Ni±Sisystem, Thermochimica Acta 337 (1999) 187-193[15].H ee Jin Jeong , Seung Yol Jeong ,Young Min Shin , Dual-catalyst growth ofvertically aligned carbon nanotubes at low temperature in thermal chemical vapor deposition, Chemical Physics Letters 361 (2002) 189–195[16].I ng-Chi Leu*, Min-Hsiung Hon, Nucleation behavior of silicon carbide whiskersgrown by chemical vapor deposition, Journal of Crystal Growth 236 (2002) 171–175[17].I ng-Chi Leu, et al Factors determining the diameter of silicon carbide whiskersprepared by chemical vapor deposition, Materials chemistry and physics 56(1998),256-561.。

【论文】半导体纳米材料论文fulltext2图文精

【论文】半导体纳米材料论文fulltext2图文精

【关键字】论文BRIEF COMMUNICATIONPreparation and photoelectric properties of mesoporous ZnO filmsMing Ming Wu •Yue Shen •Feng Gu •Yi An Xie •Jian Cheng Zhang •Lin Jun WangReceived:24June 2009/Accepted:21October 2009/Published online:6November 2009ÓSpringer Science+Business Media,LLC 2009Abstract Mesoporous ZnO films doped with Ti 4?(M-ZnOhave been prepared by doping process and sol–gel method.The films have mesoporous structures and consist of nano-crystalline phase,as evidenced from small angle X-ray diffraction and high resolution transmission electron microscopy.The wide angle X-ray diffraction of M-ZnO films confirms that M-ZnO has hexagonal wurtzite structure and ternary ZnTiO3phases.Ultraviolet–visible transmittance spectra,absorbance spectra and energy gaps of the films were measured.The Eg of M-ZnO is intensity of M-ZnO centered at 380nm increases obviously with the excitation power,which is due to the doping process and enhanced emiss ion efficiency.M-ZnO thin films display a positive photovoltaic effect compared to mesoporous TiO 2(M-TiO 2films.Keywords Photoelectric propertiesÁMesoporous ÁZnO ÁTiO 21IntroductionIt has been recently shown that semiconducting mesoporous metal oxides,e.g.,SnO 2[1,2]or TiO 2[3],with large specific surface areas and uniform pore widths show interesting properties which are superior to non porous samples of the same metal oxides.Zinc oxide (ZnOis attracting tremendous research interest due to its vast spectrum properties and applications.ZnO is an n-type direct band-gap semiconductorwith E g =3.37eV and an exciton-binding energy of 60meV.It has been applied for light-emitting diodes [4–6],lasers [7],photovoltaic solar cells [8],UV-photodetectors [9]and sensors [10].Particularly,it has attracted great attention in Dye-sensitized solar cells (DSSC.To date,the highest solar-to-electric conversion effi-ciency of over 11%has been achieved with films that consist of mesoporous TiO 2nanocrystallites sensitized by ruth e-nium-based dyes [11].Besides the optical properties similar to TiO 2,ZnO has other advantages such as higher light absorbance below 400nm than TiO 2[12],improved elec-tronic transfer rate and hindered dark current generation [13,14].Nevertheless,ZnOnano structure electrodes seem to have insufficient internal surface areas,which limits their energy conversion efficiency at a relatively low level,for example,1.5–2.4%for ZnO nanocrystalline films [15–17],0.5–1.5%for ZnO nanowire films [18–20],2.7–3.5%for uniform ZnO aggregate films [21,22]and 5.4%for poly-disperse ZnO aggregates [8].In spite of a great deal of effort to successfully synthesize mesoporous ZnO powders successfully [23,24],however,many barriers still exist due to the intrinsic properties of zinc versus silicon.To the best of our knowledge,there were few reports about ordered mesoporous ZnO thin film prepared by wet chemical method.The main hurdles in the synthesis of well-ordered mesoporous ZnO are the high reactivity of Zn ion precursors toward hydro lysis [25]and difficulty for Zn to form the three-dimensional network structure of Zn-O as compared to Si and Ti [26].In this work,we report a highly reproducible synthetic method to produce thermally stable M-ZnO films through doping process and sol–gel method.Photoelectric proper-ties of M-ZnO films were studied and compared with M-TiO 2films,which can get the highest solar-to-electric conversion efficiency.ÁY.Shen (&ÁF.Gu Á Á ÁSchool of Materials Science and Engineering,Shanghai University,Shanghai 200072,Chinae-mail:yueshen@;J Sol-Gel Sci Technol (201053:470–474DOI 10.1007/s10971-009-2099-72ExperimentalThe Pluronic P123triblock co polymer(EO20PO70EO20 with a molar weightof5800was kindly donated by BASF. All other chemicals were of analytical grade and used as received.M-ZnOfilms were prepared by doping process and sol–gel method via the following procedure:1.6ml concentrated HCl was slowly added to0.17ml tetrabutyl titanate(TBOT, [98%purityand2.085g zinc acetate dihydrate(Zn(Ac2, [99%purityat room temperature under vigorous stirring. Separately,0.75g P123wasfirst dissolved in8.3ml 1-butanol([99%purity,then added to the HCl/TBOT/ Zn(Ac2solution.At last,2ml acetylacetone(AcAcwas added.This solution was subsequently aged with stirring at room temperature for6h.The molar ratio of P123/1-buta-nol/Zn(Ac2/TBOT//AcAcwas0.013:9:0.95:0.05:2:2.M-ZnOfilms were prepared by spin coating the freshsolution onto Indium tin oxides(ITOsubstrate at900rpm for10s and3,300rpmfor20s.The as-synthesizedfilms were aged at40°C for1days and then annealed at120°C for5h at vacuum.The thickfilms were prepared by repeating the above stepsfor5times.Thefilms were sub-sequently calcined at a rate of1K min-1to350°C for5h. ITO glasses had been eroded to form plan electrodes before the spin coating process,and cleaned successively in de-ionized water,acetone and ethanol,for10min each.For ease of comparison,we prepared mesoporous TiO2(M-TiO2thin films using the same process.Themolar ratio of P123/ 1-butanol/TBOT/HCl/AcAc was0.013:9:1:2:2.The thick-ness of thinfilms is about100nm.Thefilms were characterized by(X-ray diffractometer, RigakuD/MAX-2550,Tokyowith Cu K a radiation (k=1.54056A˚,operated at40kV and200mA.The small angle scanning range was from0.5°to3°with a scanning rate of0.25°min-1.Transmission electron microscopic(TEMimages of M-ZnO thinfilms were obtained using Japan JEM-2010F microscope operating at an acceleration voltage of200kV.A JASCO V570spec-trophotometer was used to measure the optical spectra of the thinfilms.PL spectra were measured at room temper-ature with a spectrometer(Horiba Jobin Yvon HR800 using the excitation source of the325nm line of a He-Cd laser.Current-voltage measurements were carried out by semiconductor characterization system(Keithley4200, Americawith a tungsten lamp(250W.All measurements were performed at room temperature in air.3Results and discussionsSAXRD and HRTEM are two typical ways to investigate the order properties of mesoporous materials.The SAXRD patterns of M-ZnO and M-TiO2thinfilms are shown in Fig.1,and illustrate characteristic peaks at2h=0.62°and 0.75°,respectively,suggesting that the M-ZnO and M-TiO2thinfilms exhibited mesoporous structure.The diameter/d value,determined as distance between meso walls,is calculated from the2h values of the characteristic peaks by the Bragg equation. Further structural characterization of M-ZnO was per-formed using HRTEM and is shown in presents a honeycomb-like porous structure and the pore size is conforming to the results of SAXRD.In image(b, there are obviou s lattice fringes,which indicate thefilms have nano-crystalline phase structure.Figure3shows the wide angle X-ray diffraction patterns of M-ZnO thickfilms(on ITO substratesand ITO sub-strates,respectively.It can be seen that M-ZnO thickfilms exhibit hexagonal wurtzite structure and ternary ZnTiO3 phases,together.Yet no peaks corresponding to titanium and/or titanium oxide were detected.The crystal latticeconstants of M-ZnO calculated from the wide-angle X-ray diffraction are a=3.243A˚and c=5.190A˚,which are close to the card JCPDS No.36-1451,a=3.250A˚and c=5.207A˚.The differences result from the introduction of Ti ion in ZnO,because the Ti4?radius(0.68A˚is smaller than that of Zn2?(0.74A˚.The slight change of lattice parameters of M-ZnOconfirms that the Ti io ns have been incorporated into the ZnO lattice.Ultraviolet-visible(UV/vistransmittance spectra of M-ZnO and M-TiO2thinfilms were measured in Fig.4. Compared to the M-TiO2thinfilm,the fundamental transmittance edge of the M-ZnO thinfilm shows a blue shift fro m350to300nm.The inset graph is the absorbance spectra of M-ZnO and M-TiO2thinfilms.It illustrates that the absorption rate of M-ZnO is greater than that of M-TiO2in the visible range,suggesting the highzinc Fig.1SAXRD patterns of(aM-ZnO and(bM-TiO2content M-ZnO composite material can increase the light-harvesting capability as photoelectrode film.The plot of (a h m 1/2versus h m of M-ZnO and M-TiO 2films is shown in Fig.5,where a is the absorption coefficient,h m is the photon energy.Following the well-known Tauc function:(a h m 1/2µ(h m -Egand extrapolating the linear portion to (a h m 1/2=0,the optical-gap energy (Egcan be deter-mined.It could be found that the Eg of M-ZnO and M-TiO 2were 3.25and 3.37eV,respectively.Figure 6shows the room-temperature PL spectra of M-ZnO thick films as a function of the excitation power density.The five excitation power intensities are 2,20,50,100,and 200mW,respectively.The spot radius is 1l m.Dominant emission peaks of M-ZnO centered at 380nm,corresponding to 3.26eV,are ascribed to direct electron-hole recombination which should be equal to the M-ZnO band gap.It is worth noting that there is asignificantFig.2TEM images of a M-ZnO (50,0009and b M-ZnO (200,0009Fig.3The wide angle X-ray diffraction of M-ZnO thick films and ITOsubstratesFig.4Transmittance spectra of (a M-ZnO and (b M-TiO 2(inset:UV/vis absorbance spectra of (a M-ZnO and (b M-TiO 2Fig.5Energy gap (Egof (a M-ZnO and (b M-TiO 2increase of PL intensity of M-ZnO thick films at 380nm as compared to the visible bands emission with excitation powers increasing from 2to 200mW.This result is con-sistent to literature [27]and can be expected to be caused by the doping process due to enhanced emission efficiency from free exciton emission [27].For M-ZnO films,Ti atoms occupy Zn atom sites in the lattice of ZnO.When incident UV light excite the carriers in the films,the photocarriers may escape more easily from Ti ions than from Zn ions,which leads to the quick diffusion of excitons and increased exciton concentration in the M-ZnO films.Current-voltage properties of M-ZnO and M-TiO 2thin films were tested in dark and under irradiation for 5s with a tungsten lamp (250W,height to the film was 15cm.As shown in Fig.7b,photoconductivity of the M-TiO 2thin film was 6.023910-10S and dark conductivity was 1.070910-9S at bias voltage of 1V,photoconductivitydecreased about 1.8times under irradiation compared with that in thedark.However,under the same irradiation condition,it was interesting to find that the M-ZnO thin film exhibits a positive p hotovoltaic effect.Photoconduc-tivity of the M-ZnO thin film reached 9.718910-7S while dark conductivity was 3.256910-7S,photocon-ductivity increased about 3times as shown in TiO 2was widely used in DSSC,it has a low electron transfer rate and high combination rate of the pair of excited electrons [8,9],which induced a negative pho-tovoltaic effect itself.While ZnO has very high electron mobility,which is about 155cm 2V -1s -1[28],ZnO materials can improve the electronic transfer rate and hinder the dark current generation [13,14].Furthermore,it contains some intrinsic defects,which can act as capture centers of photoelectrons andthereby stop the recombina-tion of photoelectrons and photo-holes.This may improve the energy conversion efficiency of M-ZnO in DSSC.4ConclusionIn conclusion,M-ZnO films doped with Ti 4?were pre-pared by sol–gel and spin coating method.Eg of M-ZnO is 3.25eV,which is smaller than that of bulk ZnO.M-ZnO films exhibit hexagonal wurtzite structure and ternary ZnTiO 3phases.The PL intensi ty of M-ZnO centered at 380nm is increased obviously with the excitation power,which is expected to be caused by enhanced emission efficiency from free excitonemission.Current-voltage properties of M-ZnO films display a positive photovoltaic effect and indicate the promising applications in DSSC.Acknowledgments The work was supported by Innovation Pro-gram of Shanghai Municipal Education Commission (08YZ08,AM and other Research Foundation of Shanghai City Committee of Sci-ence and Technology(0852*******,0752nm016,07JC14058and Shanghai Leading Academic Disciplines(S30107.We thank Dr.Qiang Li,Bo Lu and Jian Huang for their assistance in the measurement at Shanghai University.References1.Wagner T,Kohl CD,Fro¨ba M,Tiemann M (2006Sensors 6:3182.Hyodo T,Abe S,Shimizu Y,Egashira M (2003Sens Actuators B 93:5903.Choi H,Stathatos E,Dionysiou DD (2006Appl Catal B 63:604.Keem K,Jeong DY,Kim S,Lee MS,Yeo IS,Chung U,Moon JT (2006Nano Lett 6:14545.Konenkamp R,Word RC,Godinez M (2005Nano Lett 5:20056.Spanhel L (2008J Sol-Gel Sci Technol 39:77.Kim YJ,Shang HM,Cao GZ (2006J Sol-Gel Sci Technol 38:798.Zhang QF,Chou TP,Russo B,Jenekhe SA,Cao GZ (2008Angew Chem 120:24369.Monroy E,Omnes F,Calle F (2003Semicond Sci Technol 18:3310.Yan CL,Xue DF (2007J Alloys Compounds431:241Fig.6PL spectra of M-ZnO thick films with various excitation power densities at roomtemperatureFig.7Current-voltage characteristics of a M-ZnO and b M-TiO 2(filled square in dark,(filled triangle under irradiation11.Gra¨tzel M(2005Inorg Chem44:684112.Sakthivel S,Neppolian B,Shankar MV,Arabindoo B,Palanich-amy M,Murugesan V(2003Sol Energy Mater Sol Cells77:6513.Mane RS,Lee WJ,Pathan HM(2005J Phys Chem B109:2425414.Wang ZS,Huang CH,Huang YY(2001Chem Mater13:67815.Otsuka A,Funabiki K,Sugiyama N,Yoshida T(2006Chem Lett35:66616.Zeng LY,Dai SY,Xu WW,Wang KJ(2006Plasma Sci Technol8:17217.Lee WJ,Suzuki A,Imaeda K,Okada H,Wakahara A,Yoshida A(2004Jpn J Appl Phys43:152w M,Greene LE,Johnson JC,Saykally R,Yang PD(2005Nat Mater44:5519.Baxter JB,Aydil ES(2005Appl Phys Lett86:05311420.Pasquier AD,Chen HH,Lu YC(2006Appl Phys Lett89:321.Zhang QF,Chou TP,Russo B,Jenekhe SA,Cao GZ(2008AdvFunct Mater18:165422.Chou TP,Zhang QF,Fryxell GE,Cao GZ(2007Adv Mater19:258823.Wagner T,Waitz T,Roggenbuck J,Fro¨ba M,Kohl CD,TiemannM(2007Thin Solid Films515:836024.Polarz S,Orlov AV,Schu¨th F,Lu AH(2007Chem Eur J13:59225.Soler-Illia GJ,Sanchez C,Lebeau B,Patarin J(2002Chem Rev102:409326.Yang PD,Zhao DY,Margolese DI(1999Chem Mater11:281327.Zhang Y,Zhang ZY,Lin BX,Fu ZX,Xu J(2005J Phys Chem B109:1920028.Kaidashev EM,Lorenz M,von Wenckstern H,Rahm A,Sem-melhack H-C,Han K-H,Benndorf G,Bundesmann C,Hochmuth H,Grundmann M(2003Appl Phys Lett82:3901此文档是由网络收集并进行重新排版整理.word可编辑版本!。

半导体材料研究进展分析论文

半导体材料研究进展分析论文

半导体材料研究进展分析论文摘要本文重点对半导体硅材料,GaAs和InP单晶材料,半导体超晶格、量子阱材料,一维量子线、零维量子点半导体微结构材料,宽带隙半导体材料,光子晶体材料,量子比特构建与材料等目前达到的水平和器件应用概况及其发展趋势作了概述。

最后,提出了发展我国半导体材料的建议。

关键词半导体材料量子线量子点材料光子晶体1半导体材料的战略地位上世纪中叶,单晶硅和半导体晶体管的发明及其硅集成电路的研制成功,导致了电子工业革命;上世纪70年代初石英光导纤维材料和GaAs激光器的发明,促进了光纤通信技术迅速发展并逐步形成了高新技术产业,使人类进入了信息时代。

超晶格概念的提出及其半导体超晶格、量子阱材料的研制成功,彻底改变了光电器件的设计思想,使半导体器件的设计与制造从“杂质工程”发展到“能带工程”。

纳米科学技术的发展和应用,将使人类能从原子、分子或纳米尺度水平上控制、操纵和制造功能强大的新型器件与电路,必将深刻地影响着世界的政治、经济格局和军事对抗的形式,彻底改变人们的生活方式。

2几种主要半导体材料的发展现状与趋势2.1硅材料从提高硅集成电路成品率,降低成本看,增大直拉硅(CZ-Si)单晶的直径和减小微缺陷的密度仍是今后CZ-Si发展的总趋势。

目前直径为8英寸(200mm)的Si单晶已实现大规模工业生产,基于直径为12英寸(300mm)硅片的集成电路(IC‘s)技术正处在由实验室向工业生产转变中。

目前300mm,0.18μm工艺的硅ULSI生产线已经投入生产,300mm,0.13μm工艺生产线也将在2003年完成评估。

18英寸重达414公斤的硅单晶和18英寸的硅园片已在实验室研制成功,直径27英寸硅单晶研制也正在积极筹划中。

从进一步提高硅IC‘S的速度和集成度看,研制适合于硅深亚微米乃至纳米工艺所需的大直径硅外延片会成为硅材料发展的主流。

另外,SOI材料,包括智能剥离(Smartcut)和SIMOX材料等也发展很快。

半导体纳米材料

半导体纳米材料

半导体纳米材料半导体纳米材料是一种新型的材料,它在最近几十年发展迅速,因此受到越来越多关注。

它的主要优点在于可以有效地控制半导体材料的表面性质,从而使其具有更好的性能,从而在电子、化学、材料、光学、生物等领域应用广泛。

本文旨在概述半导体纳米材料的研究现状,并对其未来的发展进行展望。

第一,半导体纳米材料的研究现状。

随着人类对纳米技术的不断发展,纳米技术及其应用已经广泛发展。

最近几十年,半导体纳米材料的研究也取得了长足的进步。

半导体纳米材料主要有半导体纳米纤维和半导体纳米粒子、纳米管、纳米颗粒、晶体衍射结构等。

其中,半导体纳米粒子具有独特的电子结构,可以实现电子态和光态的转换,具有表面增强拉曼散射、表面增强旋光等特性,可以用于有机电子器件、光电器件和染料敏化太阳能电池的制备。

另外,半导体纳米纤维的电子结构丰富复杂,可以用于光传感器和有机照明等领域,可以实现低功耗大视场的高性能控制。

第二,半导体纳米材料的未来发展。

尽管近几年半导体纳米材料在很多领域取得了很大的进步,但仍有很多可以改进的地方。

今后,半导体纳米材料的发展将越来越迅速,将发挥更大的作用。

首先,将更多地应用于电子器件和光电器件的研制,如智能传感器、晶体衍射检测器和非接触式应用等。

其次,将更多地应用于材料领域,如金属氧化物/石墨烯复合材料、纳米晶体管材料和有机半导体材料等。

此外,半导体纳米材料也在生物医疗领域发挥着重要作用,如癌症诊断、生物传感器和药物传递系统等方面,有望做出更大的贡献。

综上所述,半导体纳米材料是一种新型材料,它在最近几十年发展迅速,应用广泛,具有极大的市场潜力。

未来,半导体纳米材料将发挥更大的作用,在电子器件、有机照明、生物传感器等领域发挥作用。

此外,纳米技术也将继续发展,为半导体纳米材料的发展奠定坚实的基础。

半导体纳米材料的制备及其应用

半导体纳米材料的制备及其应用

半导体纳米材料的制备及其应用随着科学技术的不断进步,各种新材料不断涌现,其中半导体纳米材料得到了越来越广泛的研究和应用。

本文就半导体纳米材料的制备及其应用进行探讨。

一、半导体纳米材料的制备1. 传统的制备方法传统的半导体材料制备一般采用物理气相沉积、化学气相沉积等方法,这些方法不仅需要高温高压,还存在着细颗粒度的问题,因此,对于制备高质量、大面积纳米材料来说并不是很适用。

2. 新兴的制备方法目前,纳米技术的快速发展推动了制备半导体纳米材料的新兴方法,如磁控溅射、电化学制备、光化学制备等。

这些方法利用了纳米尺寸下的自组装、自组装和几何约束等效应,能够制备出高质量、高效率的纳米材料,也可以通过一些物理和化学的变形制备出各种形态的材料。

二、半导体纳米材料的应用1. 光电材料半导体纳米材料具有良好的光学性能和电性能,特别是能够产生量子点效应,因此在光电领域有着广泛的应用。

比如太阳能电池、发光二极管、激光器、荧光体、光传感器等。

2. 生物医学材料纳米材料的尺寸与生物细胞的相似,易于与细胞发生调制作用,可以用于生物医学材料的制备。

半导体纳米材料在医学成像、细胞标记和药物释放等方面也有着广泛的应用。

3. 应用于环境治理半导体纳米材料在环境治理方面也有着广泛的应用。

例如利用纳米铁等半导体纳米材料处理水、土壤等环境污染问题,达到清除有害物质的目的。

三、半导体纳米材料的未来展望随着半导体纳米材料的制备技术的不断发展和成熟,其应用范围也会越来越广泛。

未来,半导体纳米材料在信息技术、新能源、环境治理、生物医学等领域将会有更多的应用。

同时,在验证新型材料的技术上,半导体纳米材料也将有更多的创新和突破。

对此,我们应该始终关注和推动半导体纳米材料的研究,不断拓展它们的应用领域。

结语总之,半导体纳米材料是一种有着广泛应用前景的新型材料。

在制备技术和应用研究上,我们应该创新思想、加强研究,为纳米科技的进一步发展提供新的思路和方向。

半导体纳米线光电子器件制备与特性研究共3篇

半导体纳米线光电子器件制备与特性研究共3篇

半导体纳米线光电子器件制备与特性研究共3篇半导体纳米线光电子器件制备与特性研究1半导体纳米线光电子器件制备与特性研究随着现代科技的不断发展,人们对电子器件的研究与应用需求越来越高。

半导体纳米线光电子器件具有体积小、能耗低、性能优异等特点,因而备受关注。

本文主要介绍半导体纳米线光电子器件的制备方法、特性研究及相关应用。

首先,我们需要了解半导体纳米线的制备方法。

传统的制备方法主要包括化学气相沉积、分子束外延、气溶胶法等。

新型纳米材料合成方法如水热法、微波法、杂化热化学气相沉积法等也正在发展中。

其中,化学气相沉积法是最常用的制备方法之一。

它通过热分解气体协同催化剂刻蚀晶体表面原子,使其向外生长形成纳米线。

使用不同的沉积条件、催化剂以及衬底等材料可以调控纳米线的形貌、尺寸和电学性质。

其次,半导体纳米线光电子器件具有许多优异的特性,其中包括:高度可控的器件结构、高灵敏度、快速响应速度及强大的光学性能等。

大量的实验研究表明,半导体纳米线作为光电子器件的灵敏元件,对可见光、紫外光及红外光等不同波长的光线都能够有良好的响应。

在应用上,半导体纳米线光电子器件可以用于光传感和光探测等领域。

最后,让我们了解一下半导体纳米线光电子器件在实际应用中的表现。

据统计,半导体纳米线光电子器件被广泛应用于新型的太阳能电池、高效光电探测器、生物传感器以及化学气体传感器中。

在太阳能电池领域中,半导体纳米线作为纳米材料,具有优异的光吸收性能和电荷传输性能,因而备受欢迎。

同时,半导体纳米线光电子器件还被广泛应用于高效、灵敏的生物传感器和化学气体传感器中,可以实现对生物、化学物质的快速检测和准确测量。

综上所述,半导体纳米线光电子器件具有制备方法简便、性能优良、应用广泛等特点。

它的研究和应用将推动光电子技术的发展并改变现有的光电子器件应用格局半导体纳米线光电子器件是一种应用广泛、具有优良特性的新型光电子材料。

通过协同催化剂刻蚀晶体表面原子,纳米线可以方便地制备出来,并可以通过不同的沉积条件、催化剂以及衬底等材料进行调控。

纳米材料在半导体器件中的应用研究

纳米材料在半导体器件中的应用研究

纳米材料在半导体器件中的应用研究第一章纳米材料的基本概念和特性纳米材料是指在纳米尺度下制备的材料,其特点是具有独特的物理、化学和生物学性质。

纳米材料的尺寸通常在1到100纳米之间,这使得它们在半导体器件中具有许多独特的应用潜力。

第二章纳米材料在半导体器件中的应用2.1 纳米材料在场效应晶体管中的应用场效应晶体管是半导体器件中最重要的元件之一,它在现代电子器件中的应用非常广泛。

纳米材料在场效应晶体管中的应用可以改善其电子运输性质和电子流动的速度,提高器件的性能。

2.2 纳米材料在光电器件中的应用纳米材料在光电器件中的应用也非常重要。

通过合理设计纳米材料的结构和组成,可以实现光电转换的高效率、高灵敏度和宽波长范围。

纳米材料的应用使得光电器件的性能得到了显著的提升,有助于推动光电子技术的发展。

2.3 纳米材料在存储器件中的应用存储器件是电子设备中不可或缺的部分,纳米材料的应用可以提升存储器件的容量和速度。

通过利用纳米材料的特殊性质,可以实现更高密度的存储和更快的数据读写速度,满足日益增长的存储需求。

第三章纳米材料在半导体器件中的研究进展3.1 纳米材料合成和制备技术的研究纳米材料的制备是实现其在半导体器件中应用的基础。

研究人员通过不同的合成和制备技术,如溶剂热法、溶胶凝胶法等,控制纳米材料的形状、尺寸和结构,以满足不同器件的需求。

3.2 纳米材料的性能研究纳米材料具有特殊的物理和化学性质,因此对其性能的研究非常重要。

研究人员通过各种表征技术,如透射电子显微镜、扫描电子显微镜等,对纳米材料的结构、形貌和物理特性进行详细分析,为其在半导体器件中的应用提供理论依据和实验验证。

3.3 纳米材料的器件性能研究研究纳米材料在实际器件中的性能表现是纳米材料在半导体器件中应用研究的重要方向。

通过制备和测试不同类型的器件,如场效应晶体管、光电器件和存储器件等,研究人员可以评估纳米材料在这些器件中的性能和潜力。

第四章纳米材料在半导体器件中的挑战与展望4.1 挑战纳米材料在半导体器件中的应用面临一些挑战。

半导体纳米材料生长机理以及应用

半导体纳米材料生长机理以及应用

半导体纳米材料生长机理以及应用半导体纳米材料的生长机理以及应用半导体纳米材料是一种具有重要科学及工程应用的纳米材料。

它们具有显著的物理和化学特性,其最大尺寸在20-100 nm之间。

半导体纳米材料特别适用于物理、化学、生物、计算机和光电子学等领域。

半导体纳米材料的生长机理是从化学原理中解释的。

本文将讨论半导体纳米材料的生长机理以及应用。

半导体纳米材料的生长机理半导体纳米材料的生长机理基于化学原理中的自组装法。

自组装是一种自上而下的建立定向性结构的方法。

半导体纳米材料的自组装生长机理包括以下几个过程:第一,可控溶剂的选择。

半导体纳米材料的制备与溶液的稳定性有关。

合适的溶剂可以提高材料的稳定性和性能。

第二,物种选择。

这包括半导体材料的选择、nanoparticle物质的化学表面修饰,以及电子传输层的选择等。

第三,可控的溶液剂剂量。

质量和形状的控制是优化制备的关键。

第四,粒子生长和配对,质量分散度的控制、缓慢的Nucleation Pathway等方面的精细控制。

半导体纳米材料的应用半导体纳米材料具有重要的科学和工程应用。

这些应用包括:第一,纳米荧光探针。

纳米荧光探针是利用金属纳米和半导体量子点的荧光性质来探测生物分子、细胞或分子的技术。

这可以用于医学、环境监测、食品检测和生物学等方面。

半导体纳米材料作为荧光探针的重要应用领域之一,也可以用于半导体为基础的太阳电池和发光二极管。

第二,纳米电子器件。

半导体纳米材料可以应用在纳米电子器件中。

例如,纳米管晶体管可以通过由金属-半导体薄膜间的传输高度限制来实现长滞留时间和高载流子迁移率。

这也可以应用于半导体纳米材料为基础的集成电路。

第三,磁性材料。

磁性半导体和磁性材料可以用于磁性存储媒介、磁性随机进存储器、医疗磁共振和生物传感器等领域。

磁性纳米颗粒的结构和形状可以通过选择正确的合成方法控制。

通过调整粒子形状和尺寸可改变磁性材料的磁化特性。

第四,生物疫苗和药物传输。

半导体纳米材料在电子器件中的应用前景

半导体纳米材料在电子器件中的应用前景

半导体纳米材料在电子器件中的应用前景随着科技的不断发展和进步,半导体纳米材料在电子器件领域中的应用前景愈加广阔。

半导体纳米材料具有较大的比表面积、量子效应以及优异的光电性能,使其成为研究和应用的热点。

本文将探讨半导体纳米材料在电子器件中的潜在应用,并分析其前景。

首先,半导体纳米材料在光电子器件领域中的应用前景十分乐观。

由于其较大的比表面积,半导体纳米材料可以提高光电转换效率,实现更高的能量转换效率。

例如,以纳米颗粒构建的太阳能电池可以吸收更多的光线,从而提高太阳能的转化效率。

此外,半导体纳米材料的量子效应也使其具有更高的光敏度和响应速度,可以用于制造高性能的光电子器件,例如高速光通信和光传感器。

因此,半导体纳米材料在光电子器件中的应用前景非常广阔。

其次,半导体纳米材料在传感器领域中也有着巨大的应用潜力。

由于其对外界环境的极其敏感性,半导体纳米材料可以制造出高灵敏度的传感器。

例如,利用纳米颗粒构成的传感器可以检测微小的环境变化,包括温度、压力、湿度等,可广泛应用于医疗、环境监测、食品安全等领域。

此外,对于气敏传感器来说,半导体纳米材料的量子效应也能提高其对气体的响应速度和灵敏度,从而实现更加精确的气体检测和分析。

因此,半导体纳米材料在传感器领域的应用前景也是非常广阔的。

此外,半导体纳米材料在能源领域中的应用也具有很大的潜力。

目前,能源短缺和环境保护问题已经成为全球性的挑战,而半导体纳米材料可以在这方面发挥重要作用。

例如,纳米颗粒构建的催化剂可以提高能源转化效率,实现更高的能源利用效率。

此外,利用半导体纳米材料制造的超级电容器可以储存更多的能量,提高能量存储密度。

因此,半导体纳米材料在能源领域中的应用可以推动可再生能源的发展,减少对传统能源的依赖,为未来的能源供应提供可持续的解决方案。

除此之外,半导体纳米材料在生物医学领域中也有着广泛的应用前景。

由于其独特的光电性能和生物相容性,半导体纳米材料可以用于生物成像、药物传递以及疾病治疗等方面。

基于半导体纳米材料的光电子器件研究

基于半导体纳米材料的光电子器件研究

基于半导体纳米材料的光电子器件研究随着现代生活中科学技术日新月异的发展,光电子器件已经成为我们日常中不可或缺的一部分。

它是指那些基于光电效应的电子元件,可以将光信号和电信号互相转化,并广泛应用于通信、计算机、光学、医疗、环保、能源等领域。

从2000年开始,随着纳米材料和纳米技术的发展,人们在光电子器件领域中投入了更多精力和资源。

而基于半导体纳米材料的光电子器件也因其崭新的物理特性和广泛的应用前景而受到了越来越多的科研人员的重视和关注。

一、半导体纳米材料的特性与制备技术半导体纳米材料指的是由纳米结构单元组成的半导体材料,其尺寸在1-100纳米之间。

与传统的宏观材料相比,半导体纳米材料具有更高的表面积和更多的表面能量,具有更强的物理、化学等响应性和特殊的电学、磁学等特性。

这些特性使得半导体纳米材料在光、电、磁等领域中有着广泛的应用前景。

半导体纳米材料的制备技术主要有物理法、化学法和生物法三类。

其中物理法主要包括薄膜生长法、电子束蒸发法、磁控溅射法、激光烧蚀法等,其制备过程相对简单而精确;化学法则是指先将所需的半导体元素转化为有机或无机前驱体,通过控制反应条件实现纳米粒子的自组装或溶剂沉淀等方式进行制备;生物法则是指利用生物体和生物分子在制备过程中进行模板导向或表面限制的制备技术。

这三种制备技术各自有其特殊的优势与限制,科研人员可以根据实际需求进行选择。

二、基于半导体纳米材料的光电子器件原理及研究进展基于半导体纳米材料的光电子器件主要有二极管、场效应管、光敏电阻、光电传感器等。

这些器件的工作原理都基于半导体材料的光电效应,即当半导体中的被激发电子和空穴在层间复合时,会发生光催化反应并产生电子或空穴,在外界的电场作用下形成电流。

在这其中,光电传感器是一种将光信号转换为电信号的器件,其在光学通信、遥感观测、医疗诊断、环保检测等领域中有着广泛的应用。

基于半导体纳米材料的光电传感器相比传统光电传感器在光谱响应、探测范围、探测灵敏度等方面有着更为优越的表现。

半导体纳米材料的生物学机制研究及其应用

半导体纳米材料的生物学机制研究及其应用

半导体纳米材料的生物学机制研究及其应用随着纳米技术的发展,纳米材料在生物学领域中的应用正变得越来越广泛。

其中,半导体纳米材料在生物学机制和应用方面都具有巨大的潜力。

本文将对半导体纳米材料在生物学机制研究及其应用方面进行探讨。

一、半导体纳米材料的生物学应用概述半导体纳米材料具有小尺寸、高比表面积、独特的光电性质、可控制的材料组成和结构等特点,这些特点使其在生物学领域中具有非常广泛的应用。

当前,半导体纳米材料主要应用于生物标记、生物成像、药物释放和生物分析等领域。

具体来说,在生物标记中,半导体纳米材料可用于细胞标记、蛋白质标记等研究,早在20世纪90年代,鲍威尔等人就发现了半导体纳米晶的生物学应用潜力,他们通过用碳化氧化硅和氧化锌的纳米晶反应在支链胺上制成固相支链化合物,从而逐渐发展出使用半导体纳米晶进行细胞标记的方法。

随后,研究者们通过改进制备方法,开发出了高度稳定、发光量较高、植物硫蛋白包裹的半导体纳米晶,可以用于研究单个细胞中蛋白质,甚至小分子的定量分析。

在生物成像方面,半导体纳米材料有着很大潜力,早期主要应用于荧光成像、二光子成像等技术。

随着研究的不断深入,人们已经开始研究利用半导体量子点作为新型顶级成像基准点的成像技术。

目前这项技术已逐渐应用于医学的生物成像领域,如用于显影检查人体组织中含有肿瘤的细胞,这将为医学诊疗带来重大的突破。

在药物释放领域,半导体纳米材料可以在特定刺激下释放药物,如纳米晶在近红外线激发下释放药物。

这项技术可以大大提高药物的治疗效果,并降低药物副作用。

在生物分析领域,半导体纳米材料主要用于荧光共振能量转移、表面增强拉曼、电化学等分析技术中。

重要的应用领域包括分子检测和生物成像。

二、半导体纳米材料在生物学机制研究中的应用半导体纳米材料的应用使得生物学家们能够更加精细、准确地进行细胞和分子探测。

例如,在肿瘤细胞调控中,半导体纳米材料的应用使得研究人员能够更清楚地了解细胞信号传递过程中所涉及的生物分子。

半导体纳米材料

半导体纳米材料

半导体纳米材料
随着科学技术的发展,人类已经取得了前所未有的进步,尤其是在材料科学领域取得了惊人的成就。

其中,半导体纳米材料发挥了重要作用,它是一种具有晶体结构、由原子、分子或原子团组成的纳米尺度材料。

它可以用来制造半导体元件、光电元件和电子器件,以满足当今社会不断变化和发展的特殊需求。

半导体纳米材料的产生离不开量子效应的影响。

它可以模拟定义的电场,使电子在半导体中可以量子随机运动。

纳米材料的制备中,可以使用原子加成反应,利用原子能量释放而形成纳米材料。

也可以选择化学气相沉积技术,利用沉积设备产生并形成半导体纳米结构。

此外,扩散层膜技术也可以用于制备半导体纳米材料。

半导体纳米材料具有多种独特性能,包括高折射率、抗热震动能力和高透明等。

它可以有效地抑制外界的外来干扰,保证元件的稳定性和功能一致性。

半导体纳米材料的加工也更容易,可以提高制造过程的效率,从而节省大量成本。

此外,半导体纳米材料还可以用于生物传感器、太阳能电池和电化学储能系统等等。

由于其优异的性能,半导体纳米材料已经在多个领域应用,以追求更高的效率和性能。

比如,它可以用于提高传感器的灵敏度和精度,并为智能车辆提供更高的安全性能;它可以应用于数据存储,提高存储密度和传输速度;它还可以应用于电子显示器,以满足现代电子产品的高分辨率和低功耗需求。

总的来说,半导体纳米材料在科学领域的发展极具前景,其特殊
性能也使它在提高现代科技产品功能性能方面发挥了重要作用,为使现代科技产品实现更多可能性提供了可能性。

纳米材料综述论文

纳米材料综述论文

纳米材料综述论文纳米材料综述1 引言纳米材料是指晶粒尺寸为纳米级(10-9米)的超细材料,它的微粒尺寸大于原子簇,小于通常的微粒,一般为100一102nm。

它包括体积分数近似相等的两个部分:一是直径为几个或几十个纳米的粒子;二是粒子间的界面。

前者具有长程序的晶状结构,后者是既没有长程序也没有短程序的无序结构。

1984年德国萨尔兰大学的Gleiter以及美国阿贡试验室的Siegel 相继成功地制得了纯物质的纳米细粉。

Gleiter在高真空的条件下将粒径为6nm的Fe粒子原位加压成形,烧结得到纳米微晶块体,从而使纳米材料进入了一个新的阶段。

1990年7月在美国召开的第一届国际纳米科学技术会议,正式宣布纳米材料科学为材料科学的一个新分支。

从材料的结构单元层次来说,它介于宏观物质和微观原子、分子的中间领域。

在纳米材料中,界面原子占极大比例,而且原子排列互不相同,界面周围的晶格结构互不相关,从而构原子排列互不相同,界面周围的晶格结构互不相关,从而构.在纳米材料中,纳米晶粒和由此而产生的高浓度晶界是它的两个重要特征。

纳米晶粒中的原子排列已不能处理成无限长程有序,通常大晶体的连续能带分裂成接近分子轨道的能级,高浓度晶界及晶界原子的特殊结构导致材料的力学性能、磁性、介电性、超导性、光学乃至热力学性能的改变。

纳米相材料和其他固体材料都是由同样的原子组成,只不过这些原子排列成了纳米级的原子团,成为组成这些新材料的结构粒子或结构单元。

其常规纳米材料中的基本颗粒直径不到l00nm,包含的原子不到几万个。

一个直径为3nm的原子团包含大约900个原子,几乎是英文里一个句点的百万分之一,这个比例相当于一条300多米长的帆船跟整个地球的比例。

2 纳米材料特性一般在宏观领域中,某种物质固体的理化特性与该固体的尺度大小无关。

当物质颗粒小于100 nm时,物质本身的许多固有特性均发生质的变化。

这种现象称为“纳米效应”。

纳米材料具有三大效应:表面效应、小尺寸效应和宏观量子隧道效应。

半导体纳米材料的制备及其应用研究

半导体纳米材料的制备及其应用研究

半导体纳米材料的制备及其应用研究引言半导体纳米材料是一种在材料科学领域备受关注的材料。

它的尺寸通常小于100纳米,与传统的宏观材料相比,具有独特的物理、化学和光学性质。

半导体纳米材料的制备技术也随着科技的发展而不断创新,这为半导体材料在太阳能电池、LED技术、催化剂等领域的应用提供了新的可能性。

制备技术半导体纳米材料的制备方法有很多种,其中最常见的是溶液法、热蒸发法和气相沉积法。

溶液法指的是将金属离子或半导体材料在特定的溶剂中过渡到纳米晶中的制备方法。

这种方法简单易行,适用于大规模制备。

但由于溶液浓度和成分的难以控制,所以纳米晶的大小和形状难以精细调控。

热蒸发法指的是利用热能将金属材料蒸发到含氧气体的环境中,通过氧化反应生成氧化物,再通过还原反应合成纳米晶的方法。

这种方法可以精确控制纳米晶的大小和形态,但仅适用于少数的半导体材料,而且对反应条件要求严格。

气相沉积法指的是将金属气态化合物或半导体材料放入反应气室中,在高温和低压下发生反应,生成纳米晶。

这种方法可以在较低温度下制备出高纯度的材料,同时还可以控制纳米晶的大小和形状。

应用研究1. 太阳能电池太阳能电池是一种将太阳光能转化成电能的装置。

半导体纳米材料由于具有较大的比表面积和更好的光电性能,因此在太阳能电池等领域得到了广泛应用。

以染料敏化太阳能电池(DSSC)为例,它采用了一种特殊的染料涂层,将太阳能转化成电能。

而这种染料敏化层通常使用含有纳米粒子的半导体材料,如二氧化钛纳米晶。

2. LED技术LED技术(发光二极管)是一种基于半导体材料电致发光原理的新型光源技术。

半导体纳米材料由于其在大小、形状和结构上的巨大优势,使得其在LED技术中广泛应用。

利用半导体纳米材料可以获得更高的光效和更好的可调性。

此外,半导体纳米材料还可以应用于硅基LED技术中,研究人员可以通过调控硅基LED中的SiGe准分子态的能带,制备高效率的白光LED。

3. 催化剂半导体纳米材料在催化剂研究中也发挥了重要作用。

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BRIEF COMMUNICATIONPreparation and photoelectric properties of mesoporous ZnO filmsMing Ming Wu •Yue Shen •Feng Gu •Yi An Xie •Jian Cheng Zhang •Lin Jun WangReceived:24June 2009/Accepted:21October 2009/Published online:6November 2009ÓSpringer Science+Business Media,LLC 2009Abstract Mesoporous ZnO films doped with Ti 4?(M-ZnO)have been prepared by doping process and sol–gel method.The films have mesoporous structures and consist of nano-crystalline phase,as evidenced from small angle X-ray diffraction and high resolution transmission electron microscopy.The wide angle X-ray diffraction of M-ZnO films confirms that M-ZnO has hexagonal wurtzite structure and ternary ZnTiO 3phases.Ultraviolet–visible transmittance spectra,absorbance spectra and energy gaps of the films were measured.The Eg of M-ZnO is 3.25eV.Photoluminescence intensity of M-ZnO centered at 380nm increases obviously with the excitation power,which is due to the doping process and enhanced emission efficiency.M-ZnO thin films display a positive photovoltaic effect compared to mesoporous TiO 2(M-TiO 2)films.Keywords Photoelectric properties ÁMesoporous ÁZnO ÁTiO 21IntroductionIt has been recently shown that semiconducting mesoporous metal oxides,e.g.,SnO 2[1,2]or TiO 2[3],with large specific surface areas and uniform pore widths show interesting properties which are superior to non porous samples of the same metal oxides.Zinc oxide (ZnO)is attracting tremendous research interest due to its vast spectrum properties and applications.ZnO is an n-type direct band-gap semiconductorwith E g =3.37eV and an exciton-binding energy of 60meV.It has been applied for light-emitting diodes [4–6],lasers [7],photovoltaic solar cells [8],UV-photodetectors [9]and sensors [10].Particularly,it has attracted great attention in Dye-sensitized solar cells (DSSC).To date,the highest solar-to-electric conversion effi-ciency of over 11%has been achieved with films that consist of mesoporous TiO 2nanocrystallites sensitized by ruthe-nium-based dyes [11].Besides the optical properties similar to TiO 2,ZnO has other advantages such as higher light absorbance below 400nm than TiO 2[12],improved elec-tronic transfer rate and hindered dark current generation [13,14].Nevertheless,ZnO nanostructure electrodes seem to have insufficient internal surface areas,which limits their energy conversion efficiency at a relatively low level,for example,1.5–2.4%for ZnO nanocrystalline films [15–17],0.5–1.5%for ZnO nanowire films [18–20],2.7–3.5%for uniform ZnO aggregate films [21,22]and 5.4%for poly-disperse ZnO aggregates [8].In spite of a great deal of effort to successfully synthesize mesoporous ZnO powders successfully [23,24],however,many barriers still exist due to the intrinsic properties of zinc versus silicon.To the best of our knowledge,there were few reports about ordered mesoporous ZnO thin film prepared by wet chemical method.The main hurdles in the synthesis of well-ordered mesoporous ZnO are the high reactivity of Zn ion precursors toward hydrolysis [25]and difficulty for Zn to form the three-dimensional network structure of Zn-O as compared to Si and Ti [26].In this work,we report a highly reproducible synthetic method to produce thermally stable M-ZnO films through doping process and sol–gel method.Photoelectric proper-ties of M-ZnO films were studied and compared with M-TiO 2films,which can get the highest solar-to-electric conversion efficiency.M.M.Wu ÁY.Shen (&)ÁF.Gu ÁY.A.Xie ÁJ.C.Zhang ÁL.J.WangSchool of Materials Science and Engineering,Shanghai University,Shanghai 200072,Chinae-mail:yueshen@;yueshen126@J Sol-Gel Sci Technol (2010)53:470–474DOI 10.1007/s10971-009-2099-72ExperimentalThe Pluronic P123triblock co polymer(EO20PO70EO20) with a molar weight of5800was kindly donated by BASF. All other chemicals were of analytical grade and used as received.M-ZnOfilms were prepared by doping process and sol–gel method via the following procedure:1.6ml concentrated HCl was slowly added to0.17ml tetrabutyl titanate(TBOT, [98%purity)and2.085g zinc acetate dihydrate(Zn(Ac)2, [99%purity)at room temperature under vigorous stirring. Separately,0.75g P123wasfirst dissolved in8.3ml 1-butanol([99%purity),then added to the HCl/TBOT/ Zn(Ac)2solution.At last,2ml acetylacetone(AcAc)was added.This solution was subsequently aged with stirring at room temperature for6h.The molar ratio of P123/1-buta-nol/Zn(Ac)2/TBOT//AcAc was0.013:9:0.95:0.05:2:2.M-ZnOfilms were prepared by spin coating the freshsolution onto Indium tin oxides(ITO)substrate at900rpm for10s and3,300rpm for20s.The as-synthesizedfilms were aged at40°C for1days and then annealed at120°C for5h at vacuum.The thickfilms were prepared by repeating the above steps for5times.Thefilms were sub-sequently calcined at a rate of1K min-1to350°C for5h. ITO glasses had been eroded to form plan electrodes before the spin coating process,and cleaned successively in de-ionized water,acetone and ethanol,for10min each.For ease of comparison,we prepared mesoporous TiO2(M-TiO2)thin films using the same process.The molar ratio of P123/ 1-butanol/TBOT/HCl/AcAc was0.013:9:1:2:2.The thick-ness of thinfilms is about100nm.Thefilms were characterized by(X-ray diffractometer, RigakuD/MAX-2550,Tokyo)with Cu K a radiation (k=1.54056A˚),operated at40kV and200mA.The small angle scanning range was from0.5°to3°with a scanning rate of0.25°min-1.Transmission electron microscopic(TEM)images of M-ZnO thinfilms were obtained using Japan JEM-2010F microscope operating at an acceleration voltage of200kV.A JASCO V570spec-trophotometer was used to measure the optical spectra of the thinfilms.PL spectra were measured at room temper-ature with a spectrometer(Horiba Jobin Yvon HR800) using the excitation source of the325nm line of a He-Cd laser.Current-voltage measurements were carried out by semiconductor characterization system(Keithley4200, America)with a tungsten lamp(250W).All measurements were performed at room temperature in air.3Results and discussionsSAXRD and HRTEM are two typical ways to investigate the order properties of mesoporous materials.The SAXRD patterns of M-ZnO and M-TiO2thinfilms are shown in Fig.1,and illustrate characteristic peaks at2h=0.62°and 0.75°,respectively,suggesting that the M-ZnO and M-TiO2thinfilms exhibited mesoporous structure.The diameter/d value,determined as distance between meso walls,is around14.23and11.76nm calculated from the2h values of the characteristic peaks by the Bragg equation. Further structural characterization of M-ZnO was per-formed using HRTEM and is shown in Fig.2.Image(a) presents a honeycomb-like porous structure and the pore size is conforming to the results of SAXRD.In image(b), there are obvious lattice fringes,which indicate thefilms have nano-crystalline phase structure.Figure3shows the wide angle X-ray diffraction patterns of M-ZnO thickfilms(on ITO substrates)and ITO sub-strates,respectively.It can be seen that M-ZnO thickfilms exhibit hexagonal wurtzite structure and ternary ZnTiO3 phases,together.Yet no peaks corresponding to titanium and/or titanium oxide were detected.The crystal lattice constants of M-ZnO calculated from the wide-angle X-ray diffraction are a=3.243A˚and c=5.190A˚,which are close to the card JCPDS No.36-1451,a=3.250A˚and c=5.207A˚.The differences result from the introduction of Ti ion in ZnO,because the Ti4?radius(0.68A˚)is smaller than that of Zn2?(0.74A˚).The slight change of lattice parameters of M-ZnO confirms that the Ti ions have been incorporated into the ZnO lattice.Ultraviolet-visible(UV/vis)transmittance spectra of M-ZnO and M-TiO2thinfilms were measured in Fig.4. Compared to the M-TiO2thinfilm,the fundamental transmittance edge of the M-ZnO thinfilm shows a blue shift from350to300nm.The inset graph is the absorbance spectra of M-ZnO and M-TiO2thinfilms.It illustrates that the absorption rate of M-ZnO is greater than that of M-TiO2in the visible range,suggesting the highzinc Fig.1SAXRD patterns of(a)M-ZnO and(b)M-TiO2content M-ZnO composite material can increase the light-harvesting capability as photoelectrode film.The plot of (a h m )1/2versus h m of M-ZnO and M-TiO 2films is shown in Fig.5,where a is the absorption coefficient,h m is the photon energy.Following the well-known Tauc function:(a h m )1/2µ(h m -Eg)and extrapolating the linear portion to (a h m )1/2=0,the optical-gap energy (Eg)can be deter-mined.It could be found that the Eg of M-ZnO and M-TiO 2were 3.25and 3.37eV,respectively.Figure 6shows the room-temperature PL spectra of M-ZnO thick films as a function of the excitation power density.The five excitation power intensities are 2,20,50,100,and 200mW,respectively.The spot radius is 1l m.Dominant emission peaks of M-ZnO centered at 380nm,corresponding to 3.26eV,are ascribed to direct electron-hole recombination which should be equal to the M-ZnO band gap.It is worth noting that there is asignificantFig.2TEM images of a M-ZnO (50,0009)and b M-ZnO (200,0009)Fig.3The wide angle X-ray diffraction of M-ZnO thick films and ITOsubstratesFig.4Transmittance spectra of (a )M-ZnO and (b )M-TiO 2(inset:UV/vis absorbance spectra of (a )M-ZnO and (b )M-TiO 2)Fig.5Energy gap (Eg)of (a )M-ZnO and (b )M-TiO 2increase of PL intensity of M-ZnO thick films at 380nm as compared to the visible bands emission with excitation powers increasing from 2to 200mW.This result is con-sistent to literature [27]and can be expected to be caused by the doping process due to enhanced emission efficiency from free exciton emission [27].For M-ZnO films,Ti atoms occupy Zn atom sites in the lattice of ZnO.When incident UV light excite the carriers in the films,the photocarriers may escape more easily from Ti ions than from Zn ions,which leads to the quick diffusion of excitons and increased exciton concentration in the M-ZnO films.Current-voltage properties of M-ZnO and M-TiO 2thin films were tested in dark and under irradiation for 5s with a tungsten lamp (250W,height to the film was 15cm).As shown in Fig.7b,photoconductivity of the M-TiO 2thin film was 6.023910-10S and dark conductivity was 1.070910-9S at bias voltage of 1V,photoconductivitydecreased about 1.8times under irradiation compared with that in the dark.However,under the same irradiation condition,it was interesting to find that the M-ZnO thin film exhibits a positive photovoltaic effect.Photoconduc-tivity of the M-ZnO thin film reached 9.718910-7S while dark conductivity was 3.256910-7S,photocon-ductivity increased about 3times as shown in Fig.7a.Although TiO 2was widely used in DSSC,it has a low electron transfer rate and high combination rate of the pair of excited electrons [8,9],which induced a negative pho-tovoltaic effect itself.While ZnO has very high electron mobility,which is about 155cm 2V -1s -1[28],ZnO materials can improve the electronic transfer rate and hinder the dark current generation [13,14].Furthermore,it contains some intrinsic defects,which can act as capture centers of photoelectrons and thereby stop the recombina-tion of photoelectrons and photo-holes.This may improve the energy conversion efficiency of M-ZnO in DSSC.4ConclusionIn conclusion,M-ZnO films doped with Ti 4?were pre-pared by sol–gel and spin coating method.Eg of M-ZnO is 3.25eV,which is smaller than that of bulk ZnO.M-ZnO films exhibit hexagonal wurtzite structure and ternary ZnTiO 3phases.The PL intensity of M-ZnO centered at 380nm is increased obviously with the excitation power,which is expected to be caused by enhanced emission efficiency from free exciton emission.Current-voltage properties of M-ZnO films display a positive photovoltaic effect and indicate 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