SnO_2溶胶生长理论与薄膜光电性能研究
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摘要
透明导电氧化物(TCO)本性上属于n-型、宽禁带、简并半导体,它将金属优良的传输性质和绝缘体透明光性质完美地结合在一起,仿如金属,更似玻璃,系“类玻璃金属”。在TCO材料族中,In203、Sn02、ZnO三系TCO获大面积工业应用,分别服役于电子显示透明电极、气体敏感元件、电压敏感元件。在全球能源日益紧张背景下,具有优异热反射性能的TCO建筑建筑节能玻璃需求非常紧迫。本论文主旨探索建筑节能玻璃问题解决途径：用溶胶—凝胶(Sol-Gel Processing:S-G)湿化学方法,制备Sb掺杂Sn02 TCO薄膜。内容聚焦在S-G涂膜工艺基础理论、掺杂Sn02半导体材料电、光性能表征两方面,循着实验制备、测试分析表征、建立模型和相关理论线路。
论文对近几十年来TCO在透明电极、热反射玻璃、纳米结构制备的研究和应用状况进行了评述。围绕溶胶镀液稳定性和搀杂Sn02薄膜制备与表征两个问题,从溶胶化学、流变学、动态光散射、薄膜热处理以及薄膜电学与光学性能表征等五个方面,深入系统展开研究分析。针对溶胶液稳定性问题,从前驱体Sn(OBun)4反应活性控制,H20、催化剂等组分对溶胶稳定性影响规律,研究了溶液反应化学;对Sn02溶胶液陈化过程中切粘度η、特征粘度[η]随时间变化关系进行实时测试,籍此测量了胶粒的平均尺寸Rz、平均分子量M随时间动态变化规律,从中获取胶团分形结构、动力学微观信息；在陈化不同时间,进行小角X光散射(SAXS)、动态光散射(DS)测试分析,光子作为探针刺探1nm-2000nm尺度内各种胶团分布、构型、组织方式、自相似性,以及胶团在溶液中的扩散行等微观信息；结合流变学、光散射,以及分子反应／聚合生长标度理论,对SnO：溶胶生长、结构建立模型,为溶胶液稳定性微观层面奠定了理论基础。制备的湿凝胶薄膜经干燥固化处理,转变为规则多孔薄膜,采用DTA、TG热分析,XRD、BET结构分析技术,研究固化过程中多孔凝胶解附脱气、凝胶结构重构、凝胶晶化等结构演变规律,并对凝胶多孔结构作出模型化描述；所制备薄膜用膜电阻分析、Hall电阻、载流子迁移率μ、透射／反射光谱、膜厚测量等测试技术,来表征薄膜的电光性能,以此研究Sb掺杂量、热处理温度对Sn02半导体导电性、载流子浓度、迁移率的影响规律。论文在工艺方法、溶胶胶团生长动力学过程、溶胶生长表征方法等方面获得一系列重要结果。
工艺方法工艺研究和半导体性质测试表明：溶胶—凝胶浸涂方法(S-G Dip-Coating)可以用于制备性能优良的Sn02重搀杂透明导电薄膜。在工艺上获得镀液稳定性调控方法；工艺基础上掌握了溶胶液镀质胶粒演变规律,可用于镀液状态和质量的检测；光电性能上,薄膜达到电阻率ρ-10-2--3Ω.cm、可见光透光率≈85-90%,反射率≈10-15%,n型载流子浓度-1020cm-3,迁移率10-80 cm2/V.S,可用于节能建筑玻璃。S-G工艺透彻研究,为大面积生产掺杂Sn02透明导电氧化物镀膜玻璃奠定工艺基础。
搀杂薄膜结构S-G工艺制备的薄膜属致密度为0.7-0.8的纳米多孔结构。载流子迁移率μ受纳米骨架壁散射机制和搀杂离子散射机制控制,相对致密薄膜电阻率高1-2个数量级。改善多孔膜致密性,增大骨架尺寸是提高导电性的关键。湿凝胶膜由结构疏松的分形胶团堆积而成,经20-700℃干燥固化过程,Sn02凝胶历经一系列结构重构,溶胶生长过程中形成的各种分形结构被破坏,结构趋于或非分形化。随固化进程推进,在20-200℃凝胶骨架表面吸附质解附蒸发,320-340℃-acac螯环分解逃逸,为380-390℃结构驰豫腾出空间。420-440℃骨架晶化为金红石相,高于550℃骨架出现粘性流动,进一步重构。热处理过程中,凝胶骨架粗化,孔径变大,但凝胶骨架径长比保持0.29-0.32不变,相对密度ρ/ρs未显著变化。热处理剧烈改变Sn02凝胶骨架结构,电性能急剧增加。干燥固化温度400℃→500℃时,ne增加26倍,电阻率ρ下降104倍。热处理也会激活普通玻璃衬底Na+、K+扩散进入薄膜,使其电性能严重劣化。
溶胶稳定性作用机理乙酰丙酮(acacH)对单体[Sn(OBun)4中心Sn原子亲核取代,形成螯合中间单体Sn(OBun)2(acac)2。较稳定的-acac螯合环有效降低了原单体的水解活性,使溶胶系保持相当好的稳定性。单体官能度从4降至2,水解缩合后胶团为准链状结构。通过acacH的控制单体活性,在常温溶液中制备出锡氧化物准线性高分子链。超额水、催化剂酸根或氨根离子,对螯合环中间单体Sn(OBun)2(acac)2的-acac螯环,亲核攻击而取代之,使主链出现支化,进而卷曲团化。对-acac螯环亲核取代,增加单体的水解官能度,剧烈改变胶团生长速度,会根本影响甚至破坏胶粒的稳定性,以及胶粒的结构。水比超过2的部分越多,支化越剧烈,当水比为3时,5分钟内就产生沉淀,胶粒生长方式已根本改变；溶液中加入常见无机酸或氨时,其酸根或氨根离子与水的作用相似,对胶粒的水解、缩合进程形成催化,加速该进程。对诸如F-的强电子给予体(Lewis强碱),可在5分钟之内使溶胶沉淀。
溶胶胶团生长过程。小角X光散射(SAXS)和动态光散射(DS)测试表明：Sn02溶胶生长初期,单体间通过水解、缩聚过程形成胶团。当胶团生长到某一临界尺度Rc≈8.0nm时,胶团在溶液中相互接触,胶团停止生长,此即初级胶团。溶胶在凝胶前后整个生长期间,尺寸为Rc初级胶团始终存在。
当胶团长至相互接触,邻近初级胶粒(链团)间按自相似构造方式,在溶胶液内形成胶团世代序列。胶团世代序列尺度为Rc、R2、R3、R4、R5、R6、R7.....后代胶团尺寸是前代胶团的某个确定倍数,这取决于较小胶团组构较大胶团的具体方式。就Sn02溶胶系而言,动态光散射给出5个世代序列,其尺寸比Rn/Rn-1≈4-6。胶团世代序列从初级胶团跨越到宏观尺度,直到体系凝胶时为无限大宏观胶团。任何一代胶团的几何结构与其他代间是相似的,只是尺度不同而已。
在临近凝胶前,胶团世代序列通过相邻键连接方式形成宏观尺寸的无限大胶团,体系转变为凝胶块。凝胶时主要为大胶团间相互连接,连接方式发生转变,按D=2.50渗流连接为空间网络,其尺寸按ζ-|Tg-t|-v陡速发散。Sol→gel转变属于一种临界相变行为。
随着溶胶—凝胶的进程推进,溶液中残存的单体在初级胶团表面不断水解缩合,使其表面逐渐光滑化,表面维度逐渐趋于2.0；同时初级胶团在溶剂中永不停息的扩散,渗入到大胶团内部和表面,进行重构,大胶团表面也逐渐光滑化。大小胶团表面和内部的结构调整和重构过程,仍属于慢团聚生长模式,其胶团平均尺度随时间仍按指数方式增长。
溶胶胶团分形结构在溶胶系凝胶以前的整个过程中,特征粘度动力学[η]-t实验曲线,很好地满足Flory-Bechtold准线性结构模型：ln[η]=(lnA+αlnΩ)+αln[x/(1-x)](x=t/Tg),证实了Sn02胶团为准线性高分子链。其分形维度D≈1.8,介于自回避无规行走链(D=1.67)和高斯无规行走链之间(D=2.0)。适当控制水比、电解质催化剂的加入量,可以控制和调整Sn02胶团的分形维度和结构形貌。在溶胶凝胶以前,无论是初期单体水解缩合形成初级胶团,还是后期由初级胶团形成胶团世代序列,组构方式是一致的,不同胶团间分形结构相同,即按照不变的分形结构生长。
慢团聚生长模式(指数生长) Sn02溶胶系在凝胶化以前,切粘度与时间满足指数增长关系：η∝exp[λ't],或Lnη-t为线性关系,胶团平均尺寸按Rz-eλt指数规律缓慢长大,后期逐渐过度到键连接渗流凝胶化生长模式。胶团世代序列存在,证实胶团长大受Oswald熟化机制控制(大团—小团团聚),属扩散控制的团簇聚合(DLCA)生长模式(该模式团簇维度为1.8),后期过度到大团—大团聚合的凝胶化模式.
表征方法针对液相溶胶体系,流变学测量可以简单、快捷地用于表征胶团的生长过程。溶胶溶液中,其切粘度η和特征粘度[η]分别对应胶团的平均尺寸Rz和平均分子量M,对η、[η]的动态观察反映了胶团尺寸和质量动力学变化关系,Rz-t, M-t。结合光散射特别是最近些年发展起来的动态光散射(DS)方法,流变学表征方法可获取大量有关几何构形、生长模式、分形结构、生长机理等丰富、深刻的信息。
整个研究工作有两个突出的创新之处。一个是在工艺方法上的创新,即绕开传统的物理真空镀膜法,引入醇盐溶胶—凝胶法(Alkyoxide Derived Sol—Gel Processing)来制备Sn02重搀杂半导体薄膜。该方法可以实现大规模连续化、低成本镀膜生产,因而有现实意义。在研究中从醇盐合成、薄膜制备到薄膜性能表征,有较透彻系统的研究和结果。镀膜溶胶液可稳定1000小时以上,薄膜性能优良,可以用于建筑节能玻璃。第二个创新是首次引入流变学测量方法,来研究溶胶液胶粒生长过程,观测溶胶胶粒尺寸和分子量随时间的动力学变化规律,得到相当深入的动力学结果。流变学测量仪器简单、操作容易、可在线原位观测,有很强的生产实践价值,同时结合光散射方法,对有自相似性的溶胶胶粒的生长、构型表征,是很好的研究方法。
Transparent conductive oxides(TCO) are attributed in nature to degenerate n-type semiconductor with wide band gap, which compromises exquisitely the conductivity of metals and the transparency of glassy insulates, and inherits transparent insulates but resembles metals closely, so being ascribed to glassy metal. Among a large TCO family, The three oxides,In2O3, SnO2, ZnO, have acquired pervasive approval in commercial use, serving as transparent electrodes of electro-optic displays, chemical sensors, and viasistors respectively. Under increasing emergency of power resources all over the world, it is ultimately urgent for building efficient window use to develop TCO coated glasses with excellent performance of heat reflectance, therefore this thesis is devoted itself to exploring a technique route employed for such efficient building glasses of energy conservation: preparing antimony-doped tin oxide(ATO) films by Sol-Gel processing(S-G), a wet chemical route, its contents focus on modeling S-G process and characterizing electrical and optical properties of the films, along with such a route of experimentation, testing characterization, modeling and establishing relevant theory.
The research and application status of TCO materials across past several decades have been reviewed in this thesis through fields of transparent electrode, heat-reflection glass, preparation and characterization of nano-structures. By putting attention concentrated on the stability of sol solutions and preparation and characterization of heavy Sb doped SnO2 films, five aspects of researches have been done in depth in the thesis:sol solution chemistry, rheology, light scattering, drying and solidification of coated gel films and characterization of electrical and optical properties of final films. For sol solution stability, reaction chemistry of hydrolysis and condensation of precursor monomers has been studed based on control of reaction activity of precursor Sn(OBun)4 by acetylacetone (acacH), and the influences of water and catalyst addition ratios on the stability of sol solution. Further efforts concentrating on observing dynamic variations of shear viscosityηand intrinsic viscosity [η] with SnO2 sol aging time, hereby the dynamic variations of average size Rz and molecule mass M of sol aggregates with aging time were observed indirectively, from which much of microscopic information of aggregate fractal feature and growth dynamics were acquired.The third,making measures of Small Angle X-ray Scattering (SAXS) and Dynamic Light Scattering(DS, or Photo Correlation Spectrum:PCS) for sol solutions at different aging time before and after sol-gelling transition, taking photon as a probe to probe into sol aggregates in the size range of 1～2000nm with respect to the size distributions, configurations, organization architecture, self-similarity, and diffusion in solution, and then combining together with rheological measures and growth theory of molecule reaction/aggregation, growth processes were reasonably modeled for SnO2 sol aggregates, which funded the microscopic theory of SnO2 sol solution stability. The fourth wet gel films developed from the tin-alkyoxide-derived sol-gel dip-coating route will transform to porous films under drying and solidification procedure, by use of DTA and TG heat analysis technologies, XRD and BET structure analysis techniques, the restructure process of wet gel films during drying and solidification procedure referred to such as desorption of the absorbed, reconfiguration and crystallization of gel skeleton was investigated and modeled. Finally electrical and optical performance was characterized by means of measuring film square resistance, Hall resistance, carrier mobility, transparency/reflectance spectrum and film thickness for obtained SnO2 films, the influences of Sb dopant amount and heat treatment temperature on conductivity, carrier concentration and mobility of Sb-doped SnO2 was hereby pronounced and modeled. Hereto a number of original results of research related to technique method, growth dynamic process of sol aggregates, electronic band structures, electrical and optical properties and characterization technologies can take into conclusions.
Process Approach It is shown from experimental surveys and the characterization of electrical and optical attributes that a transparent conductive porous SnO2:Sb film can be derived by S-G Dip-Coating route, which exhibits excellent electrical and optical performance of resistivity of p～10-2～-3 Q.cm, transparency in visible spectrum region of 85～90% and reflectance of 10～15%, n-carrier mobility of 10～80 cm2/v.s and carrier concentration of～1020cm～3,which are availably for efficient window glasses. From the view of craft, it has been perceived to control stability of sol solution for dip-coating, and sol aggregates growth process has been modeled reasonably, whose measuring method can be employed to test on line for state and performance of sol coating solutions. The incisive investigations on S-G processing lay a solid foundation for large area production of SnO2-coated transparent conductive oxides glasses.
Porous Structures of Sb Doped SnO2 films Films derived from S—G Processing is proved nano-porous structures with relative density p/ps approximately of 0.7～0.8. Its carrier mobility is controlled by nano-skeleton scattering mechanism and impurity scattering mechanism together, film resistivity is larger 101～2 than that of dense films. For promotion of film conductivity it is key research aspect to improve its densification and to coarsen film skeletons. Wet gelling films are paved by loose aggregates of fractal structures, under drying and solidification at temperature between 20～700℃, SnO2 gels undergo a series of re-buildups but its nanoporous non-fractal structures keep invariant. The fractal structures of gelling films derived from sol-gel processing have been violated upon drying and solidifying processing, and solidified structures of films present non-fractal.As heat treatment route proceeds, the solvents and water absorbed on skeleton of gel desorb and volatilize away subsequently between 20～200℃,-acac chelates dissociate at 320～340℃,so as to make way for the relaxation of gel skeletons at 380～390℃, and the gel skeletons crystallize at 420～440℃into rutile phase. Above 550℃, skeletons become viscid and present creep, further restructuring. During the heat treatment process, the diameters of skeletons thicken from 2-3nm to 5-14nm, the pore sizes increase from lnm to 13nm, but the aspect ratio of skeletons keeps about 0.29～0.32 unchanged, the relative density p/ps of gels does not change substantially. Heat treatment processing alters largely the skeleton structures, cause to huge varieties of electricity of films. The film carrier concentration enhances by 26 times, and its resistivity reduces 4 number of grades when solidification temperature rises from 400 to 500℃. Heat treatment may actuate diffusion of Na+, K+ions into TCO layer to degrade the its performance.
The sol stability mechanisms By incorporation of acacH to control hydrolysis reaction activity of monomer [Sn(OBun)]4,it is proposed that the monomer is attacked by nucleophilic substitution of accH to form chelated intermediate Sn(OBun)2(acac)2, which is responsible for the huge reduction of activity of initial monomer and make quite stable the sol system. After formation of the chelated intermediate, the functionality for hydrolysis of initial monomer reduces from 4 to 2, leading to the formation of quasi-linear chain polymers undergoing hydrolysis and condensation reactions. The chelated intermediate Sn(OBun)2(acac)2 is attacked by extra water, radicals of acid or ammonia incorporated as catalysts at-acac chelating ring by nucleophilic substitution, causing the branching of stem chains and further the curling and rolling of them. On the other hand,the substitution of-acac chelating rings increases the hydrolysis functionality of chelated intermediates surpassing over 2, which enhances activity of the intermediates violently and the growth pace of sol clusters, influencing mostly and even violating the sol stability and the configurations of sol clusters and aggregates. The more over 2 added water ratio is, the more violent the stem chain branches, sol system precipitates in five minute at added water ratio of 3. in such case, the growth model of sol clusters changes completely. As the same mechanism as the water addition, the radical ions of acids and ammonia catalyze and accelerate hydrolysis and condensation reactions in sol process. For the introduction of strong electron donors (Lewis strong base) such as F-ions, the sol aggregates precipitate in five minute.
The Growth Process of Aggregates during Sol→Gel It has been shown from the surveys of small angle x-ray scattering(SAXS) and dynamic light scattering(DS) that monomers condense into primitive sol clusters by hydrolysis and coalescence at initial stage, when the clusters build up to a certain critical size of Rc≈8nm, clusters contact each other and cease to grow. These primitive clusters exist in sol solution though sol-gel process before gelling and after gelling.
Sol clusters neighboring each other joint into a hierarchy of sol aggregates abiding by self-similar construction as the initial clusters contact each other, whose sizes list in order: Rc,R2,R3,R4,R5R6,R7..., the size of later generation is larger a constant times than that of last generation, depending on the specific way smaller aggregates build up larger aggregates. Hierarchy of sol aggregates constructs itself from primitive clusters across macro-size aggregates up to gelling, the configuration manner of any generation is similar to that of other generation, only different from their sizes. In the case of SnO2 sol system, DS surveys demonstrate the existence of a hierarchy of five generations of sol aggregates with Rn/Rn-1≈4-6.
Near gelling, the hierarchy of sol aggregates coalesce raptly into infinite large aggregates of macroscopic size by jointing neighboringly and self-similarly bond-linking style, and sol system undergoes sol→gel transition into gelling bulk. Upon gelling bond-linkings take place principally among large aggregates, and the way aggregates coalesce change with respect to sol growth process, following percolation-linkage with fractal dimension D= 2.5, aggregates coalesce into space wetworks, average size Rz of sol aggregates tends to diverge as follows Rz∝(|1-t/tg|)-v.sol→gel transition belongs to a critical transition of percolation.
As sol-gel route proceeds, the survivals of monomers in solution attack the surface of sol primitive aggregates, and condense onto it, its surface tends smooth and surficial dimension approach to 2.0. At the same time, the primitive clusters diffuse ceaselessly in solution, and diffuse onto the surfaces and percolate into interiors of large aggregates, derive them to reconstruct, thus the surfaces of large aggregates become smooth gradually. However, the reconstruction of small and large aggregates can also attribute to slow aggregation style, and contribute to the exponential growth of sol aggregates with aging time.
Fractal configurations of sol aggregates The experimental data of dynamical relations of intrinsic viscosity of sol solutions with aging time [η]-t is in good agree with Flory-Bechtold's quasi-linear chain model ln[η]=(lnA+αlnΩ)+a ln[x/(1-x)] (x =t/tg),which verifys the proposal that the sol aggregates of SnO2 sol system belong to quasi-linear polymer chains. The fractal dimensions of such aggregates of linear chain are approximately 1.8, intervening between self-avoid random walk chain (SAW, D=5/3) and Guassian random walk chain(D=2.0). The fractal configurations and dimensions of SnO2 sol aggregates may be controlled by an adequate control of incorporation of water and catalysts. Before gelling, both primitive clusters formed in early stage by monomer reactions and hierarchy of aggregates constituted in later stage, keep the same fractal configuration though whole sol-gelling process.
Slow Aggregation Growth Model (Exponential Growth) The sol aggregates in SnO2 sol solution build up in style of the well-known slow aggregation before gelling. The experimental surveys show that shear viscosityηof sol solution satisfies the law of exponential variations with aging time:η∝exp[λ't], that is, Lnη-t keeps linear relation, the average sizes of sol aggregates meet exponential relation with aging time t:Rz～eλt. In quite later stage, sol growth transits into gelling style of bond-linking percolation. The existence of hierarchy of aggregates confirms that the growth of sol aggregates is controlled by Oswald Ripening mechanism (small cluster—large cluster aggregation) and diffusion limited cluster aggregation(DLCA) growth model,whose fractal dimension of aggregates is approximately 1.8.
Characterization Method Rheological dynamic measure may be used to characterize in situ the growth process of sol aggregates with availability and rapidity for liquid sol systems. The shear viscosityη, and intrinsic viscosity [η] are related to average size Rz and mass M of sol aggregates, rheological dynamic measures describe size and mass dynamical variations of sol aggregates with sol—gel process:Rz-t, M-t. Rheological dynamic characterization method, combining with dynamic light scattering (DS) developed recent years and other light scattering techniques, and under the theoretical frame of growth of molecule reaction/aggregation, may provides a lots of profound information of dynamics and structures related to geometrical configuration, growth mechanisms, fractal structure, growth mechanism of sol aggregates.
Two novel research results have been developed in the thesis. Firstly, a film-coating processing method for large scale production of heavy doped SnO2 coated glasses with low loss, Sol—Gel processing derived from alkyoxide, is developed up, in which sol coating solutions keep stable over 1000h with process working model being setup, prepared TCO films have excellent performance suit for efficient building windows. The second original result is introduction of a characterization method for liquid sol solution, Rheological Measuring method, which may be employed for aggregates of sol solutions to measure dynamic variations of average size Rz and mass M with time:Rz-t, M-t, and can acquire dynamical information in deep insight. Its setup is simple and measure is easily operated, has practical availability for on-line testing. Combining with light scattering measure means, Rheological Measuring method is a good measure mean of characterization of growth and structures of sol aggregates with self-similarity for liquid sol solutions.
论文对近几十年来TCO在透明电极、热反射玻璃、纳米结构制备的研究和应用状况进行了评述。围绕溶胶镀液稳定性和搀杂Sn02薄膜制备与表征两个问题,从溶胶化学、流变学、动态光散射、薄膜热处理以及薄膜电学与光学性能表征等五个方面,深入系统展开研究分析。针对溶胶液稳定性问题,从前驱体Sn(OBun)4反应活性控制,H20、催化剂等组分对溶胶稳定性影响规律,研究了溶液反应化学;对Sn02溶胶液陈化过程中切粘度η、特征粘度[η]随时间变化关系进行实时测试,籍此测量了胶粒的平均尺寸Rz、平均分子量M随时间动态变化规律,从中获取胶团分形结构、动力学微观信息；在陈化不同时间,进行小角X光散射(SAXS)、动态光散射(DS)测试分析,光子作为探针刺探1nm-2000nm尺度内各种胶团分布、构型、组织方式、自相似性,以及胶团在溶液中的扩散行等微观信息；结合流变学、光散射,以及分子反应／聚合生长标度理论,对SnO：溶胶生长、结构建立模型,为溶胶液稳定性微观层面奠定了理论基础。制备的湿凝胶薄膜经干燥固化处理,转变为规则多孔薄膜,采用DTA、TG热分析,XRD、BET结构分析技术,研究固化过程中多孔凝胶解附脱气、凝胶结构重构、凝胶晶化等结构演变规律,并对凝胶多孔结构作出模型化描述；所制备薄膜用膜电阻分析、Hall电阻、载流子迁移率μ、透射／反射光谱、膜厚测量等测试技术,来表征薄膜的电光性能,以此研究Sb掺杂量、热处理温度对Sn02半导体导电性、载流子浓度、迁移率的影响规律。论文在工艺方法、溶胶胶团生长动力学过程、溶胶生长表征方法等方面获得一系列重要结果。
工艺方法工艺研究和半导体性质测试表明：溶胶—凝胶浸涂方法(S-G Dip-Coating)可以用于制备性能优良的Sn02重搀杂透明导电薄膜。在工艺上获得镀液稳定性调控方法；工艺基础上掌握了溶胶液镀质胶粒演变规律,可用于镀液状态和质量的检测；光电性能上,薄膜达到电阻率ρ-10-2--3Ω.cm、可见光透光率≈85-90%,反射率≈10-15%,n型载流子浓度-1020cm-3,迁移率10-80 cm2/V.S,可用于节能建筑玻璃。S-G工艺透彻研究,为大面积生产掺杂Sn02透明导电氧化物镀膜玻璃奠定工艺基础。
搀杂薄膜结构S-G工艺制备的薄膜属致密度为0.7-0.8的纳米多孔结构。载流子迁移率μ受纳米骨架壁散射机制和搀杂离子散射机制控制,相对致密薄膜电阻率高1-2个数量级。改善多孔膜致密性,增大骨架尺寸是提高导电性的关键。湿凝胶膜由结构疏松的分形胶团堆积而成,经20-700℃干燥固化过程,Sn02凝胶历经一系列结构重构,溶胶生长过程中形成的各种分形结构被破坏,结构趋于或非分形化。随固化进程推进,在20-200℃凝胶骨架表面吸附质解附蒸发,320-340℃-acac螯环分解逃逸,为380-390℃结构驰豫腾出空间。420-440℃骨架晶化为金红石相,高于550℃骨架出现粘性流动,进一步重构。热处理过程中,凝胶骨架粗化,孔径变大,但凝胶骨架径长比保持0.29-0.32不变,相对密度ρ/ρs未显著变化。热处理剧烈改变Sn02凝胶骨架结构,电性能急剧增加。干燥固化温度400℃→500℃时,ne增加26倍,电阻率ρ下降104倍。热处理也会激活普通玻璃衬底Na+、K+扩散进入薄膜,使其电性能严重劣化。
溶胶稳定性作用机理乙酰丙酮(acacH)对单体[Sn(OBun)4中心Sn原子亲核取代,形成螯合中间单体Sn(OBun)2(acac)2。较稳定的-acac螯合环有效降低了原单体的水解活性,使溶胶系保持相当好的稳定性。单体官能度从4降至2,水解缩合后胶团为准链状结构。通过acacH的控制单体活性,在常温溶液中制备出锡氧化物准线性高分子链。超额水、催化剂酸根或氨根离子,对螯合环中间单体Sn(OBun)2(acac)2的-acac螯环,亲核攻击而取代之,使主链出现支化,进而卷曲团化。对-acac螯环亲核取代,增加单体的水解官能度,剧烈改变胶团生长速度,会根本影响甚至破坏胶粒的稳定性,以及胶粒的结构。水比超过2的部分越多,支化越剧烈,当水比为3时,5分钟内就产生沉淀,胶粒生长方式已根本改变；溶液中加入常见无机酸或氨时,其酸根或氨根离子与水的作用相似,对胶粒的水解、缩合进程形成催化,加速该进程。对诸如F-的强电子给予体(Lewis强碱),可在5分钟之内使溶胶沉淀。
溶胶胶团生长过程。小角X光散射(SAXS)和动态光散射(DS)测试表明：Sn02溶胶生长初期,单体间通过水解、缩聚过程形成胶团。当胶团生长到某一临界尺度Rc≈8.0nm时,胶团在溶液中相互接触,胶团停止生长,此即初级胶团。溶胶在凝胶前后整个生长期间,尺寸为Rc初级胶团始终存在。
当胶团长至相互接触,邻近初级胶粒(链团)间按自相似构造方式,在溶胶液内形成胶团世代序列。胶团世代序列尺度为Rc、R2、R3、R4、R5、R6、R7.....后代胶团尺寸是前代胶团的某个确定倍数,这取决于较小胶团组构较大胶团的具体方式。就Sn02溶胶系而言,动态光散射给出5个世代序列,其尺寸比Rn/Rn-1≈4-6。胶团世代序列从初级胶团跨越到宏观尺度,直到体系凝胶时为无限大宏观胶团。任何一代胶团的几何结构与其他代间是相似的,只是尺度不同而已。
在临近凝胶前,胶团世代序列通过相邻键连接方式形成宏观尺寸的无限大胶团,体系转变为凝胶块。凝胶时主要为大胶团间相互连接,连接方式发生转变,按D=2.50渗流连接为空间网络,其尺寸按ζ-|Tg-t|-v陡速发散。Sol→gel转变属于一种临界相变行为。
随着溶胶—凝胶的进程推进,溶液中残存的单体在初级胶团表面不断水解缩合,使其表面逐渐光滑化,表面维度逐渐趋于2.0；同时初级胶团在溶剂中永不停息的扩散,渗入到大胶团内部和表面,进行重构,大胶团表面也逐渐光滑化。大小胶团表面和内部的结构调整和重构过程,仍属于慢团聚生长模式,其胶团平均尺度随时间仍按指数方式增长。
溶胶胶团分形结构在溶胶系凝胶以前的整个过程中,特征粘度动力学[η]-t实验曲线,很好地满足Flory-Bechtold准线性结构模型：ln[η]=(lnA+αlnΩ)+αln[x/(1-x)](x=t/Tg),证实了Sn02胶团为准线性高分子链。其分形维度D≈1.8,介于自回避无规行走链(D=1.67)和高斯无规行走链之间(D=2.0)。适当控制水比、电解质催化剂的加入量,可以控制和调整Sn02胶团的分形维度和结构形貌。在溶胶凝胶以前,无论是初期单体水解缩合形成初级胶团,还是后期由初级胶团形成胶团世代序列,组构方式是一致的,不同胶团间分形结构相同,即按照不变的分形结构生长。
慢团聚生长模式(指数生长) Sn02溶胶系在凝胶化以前,切粘度与时间满足指数增长关系：η∝exp[λ't],或Lnη-t为线性关系,胶团平均尺寸按Rz-eλt指数规律缓慢长大,后期逐渐过度到键连接渗流凝胶化生长模式。胶团世代序列存在,证实胶团长大受Oswald熟化机制控制(大团—小团团聚),属扩散控制的团簇聚合(DLCA)生长模式(该模式团簇维度为1.8),后期过度到大团—大团聚合的凝胶化模式.
表征方法针对液相溶胶体系,流变学测量可以简单、快捷地用于表征胶团的生长过程。溶胶溶液中,其切粘度η和特征粘度[η]分别对应胶团的平均尺寸Rz和平均分子量M,对η、[η]的动态观察反映了胶团尺寸和质量动力学变化关系,Rz-t, M-t。结合光散射特别是最近些年发展起来的动态光散射(DS)方法,流变学表征方法可获取大量有关几何构形、生长模式、分形结构、生长机理等丰富、深刻的信息。
整个研究工作有两个突出的创新之处。一个是在工艺方法上的创新,即绕开传统的物理真空镀膜法,引入醇盐溶胶—凝胶法(Alkyoxide Derived Sol—Gel Processing)来制备Sn02重搀杂半导体薄膜。该方法可以实现大规模连续化、低成本镀膜生产,因而有现实意义。在研究中从醇盐合成、薄膜制备到薄膜性能表征,有较透彻系统的研究和结果。镀膜溶胶液可稳定1000小时以上,薄膜性能优良,可以用于建筑节能玻璃。第二个创新是首次引入流变学测量方法,来研究溶胶液胶粒生长过程,观测溶胶胶粒尺寸和分子量随时间的动力学变化规律,得到相当深入的动力学结果。流变学测量仪器简单、操作容易、可在线原位观测,有很强的生产实践价值,同时结合光散射方法,对有自相似性的溶胶胶粒的生长、构型表征,是很好的研究方法。
Transparent conductive oxides(TCO) are attributed in nature to degenerate n-type semiconductor with wide band gap, which compromises exquisitely the conductivity of metals and the transparency of glassy insulates, and inherits transparent insulates but resembles metals closely, so being ascribed to glassy metal. Among a large TCO family, The three oxides,In2O3, SnO2, ZnO, have acquired pervasive approval in commercial use, serving as transparent electrodes of electro-optic displays, chemical sensors, and viasistors respectively. Under increasing emergency of power resources all over the world, it is ultimately urgent for building efficient window use to develop TCO coated glasses with excellent performance of heat reflectance, therefore this thesis is devoted itself to exploring a technique route employed for such efficient building glasses of energy conservation: preparing antimony-doped tin oxide(ATO) films by Sol-Gel processing(S-G), a wet chemical route, its contents focus on modeling S-G process and characterizing electrical and optical properties of the films, along with such a route of experimentation, testing characterization, modeling and establishing relevant theory.
The research and application status of TCO materials across past several decades have been reviewed in this thesis through fields of transparent electrode, heat-reflection glass, preparation and characterization of nano-structures. By putting attention concentrated on the stability of sol solutions and preparation and characterization of heavy Sb doped SnO2 films, five aspects of researches have been done in depth in the thesis:sol solution chemistry, rheology, light scattering, drying and solidification of coated gel films and characterization of electrical and optical properties of final films. For sol solution stability, reaction chemistry of hydrolysis and condensation of precursor monomers has been studed based on control of reaction activity of precursor Sn(OBun)4 by acetylacetone (acacH), and the influences of water and catalyst addition ratios on the stability of sol solution. Further efforts concentrating on observing dynamic variations of shear viscosityηand intrinsic viscosity [η] with SnO2 sol aging time, hereby the dynamic variations of average size Rz and molecule mass M of sol aggregates with aging time were observed indirectively, from which much of microscopic information of aggregate fractal feature and growth dynamics were acquired.The third,making measures of Small Angle X-ray Scattering (SAXS) and Dynamic Light Scattering(DS, or Photo Correlation Spectrum:PCS) for sol solutions at different aging time before and after sol-gelling transition, taking photon as a probe to probe into sol aggregates in the size range of 1～2000nm with respect to the size distributions, configurations, organization architecture, self-similarity, and diffusion in solution, and then combining together with rheological measures and growth theory of molecule reaction/aggregation, growth processes were reasonably modeled for SnO2 sol aggregates, which funded the microscopic theory of SnO2 sol solution stability. The fourth wet gel films developed from the tin-alkyoxide-derived sol-gel dip-coating route will transform to porous films under drying and solidification procedure, by use of DTA and TG heat analysis technologies, XRD and BET structure analysis techniques, the restructure process of wet gel films during drying and solidification procedure referred to such as desorption of the absorbed, reconfiguration and crystallization of gel skeleton was investigated and modeled. Finally electrical and optical performance was characterized by means of measuring film square resistance, Hall resistance, carrier mobility, transparency/reflectance spectrum and film thickness for obtained SnO2 films, the influences of Sb dopant amount and heat treatment temperature on conductivity, carrier concentration and mobility of Sb-doped SnO2 was hereby pronounced and modeled. Hereto a number of original results of research related to technique method, growth dynamic process of sol aggregates, electronic band structures, electrical and optical properties and characterization technologies can take into conclusions.
Process Approach It is shown from experimental surveys and the characterization of electrical and optical attributes that a transparent conductive porous SnO2:Sb film can be derived by S-G Dip-Coating route, which exhibits excellent electrical and optical performance of resistivity of p～10-2～-3 Q.cm, transparency in visible spectrum region of 85～90% and reflectance of 10～15%, n-carrier mobility of 10～80 cm2/v.s and carrier concentration of～1020cm～3,which are availably for efficient window glasses. From the view of craft, it has been perceived to control stability of sol solution for dip-coating, and sol aggregates growth process has been modeled reasonably, whose measuring method can be employed to test on line for state and performance of sol coating solutions. The incisive investigations on S-G processing lay a solid foundation for large area production of SnO2-coated transparent conductive oxides glasses.
Porous Structures of Sb Doped SnO2 films Films derived from S—G Processing is proved nano-porous structures with relative density p/ps approximately of 0.7～0.8. Its carrier mobility is controlled by nano-skeleton scattering mechanism and impurity scattering mechanism together, film resistivity is larger 101～2 than that of dense films. For promotion of film conductivity it is key research aspect to improve its densification and to coarsen film skeletons. Wet gelling films are paved by loose aggregates of fractal structures, under drying and solidification at temperature between 20～700℃, SnO2 gels undergo a series of re-buildups but its nanoporous non-fractal structures keep invariant. The fractal structures of gelling films derived from sol-gel processing have been violated upon drying and solidifying processing, and solidified structures of films present non-fractal.As heat treatment route proceeds, the solvents and water absorbed on skeleton of gel desorb and volatilize away subsequently between 20～200℃,-acac chelates dissociate at 320～340℃,so as to make way for the relaxation of gel skeletons at 380～390℃, and the gel skeletons crystallize at 420～440℃into rutile phase. Above 550℃, skeletons become viscid and present creep, further restructuring. During the heat treatment process, the diameters of skeletons thicken from 2-3nm to 5-14nm, the pore sizes increase from lnm to 13nm, but the aspect ratio of skeletons keeps about 0.29～0.32 unchanged, the relative density p/ps of gels does not change substantially. Heat treatment processing alters largely the skeleton structures, cause to huge varieties of electricity of films. The film carrier concentration enhances by 26 times, and its resistivity reduces 4 number of grades when solidification temperature rises from 400 to 500℃. Heat treatment may actuate diffusion of Na+, K+ions into TCO layer to degrade the its performance.
The sol stability mechanisms By incorporation of acacH to control hydrolysis reaction activity of monomer [Sn(OBun)]4,it is proposed that the monomer is attacked by nucleophilic substitution of accH to form chelated intermediate Sn(OBun)2(acac)2, which is responsible for the huge reduction of activity of initial monomer and make quite stable the sol system. After formation of the chelated intermediate, the functionality for hydrolysis of initial monomer reduces from 4 to 2, leading to the formation of quasi-linear chain polymers undergoing hydrolysis and condensation reactions. The chelated intermediate Sn(OBun)2(acac)2 is attacked by extra water, radicals of acid or ammonia incorporated as catalysts at-acac chelating ring by nucleophilic substitution, causing the branching of stem chains and further the curling and rolling of them. On the other hand,the substitution of-acac chelating rings increases the hydrolysis functionality of chelated intermediates surpassing over 2, which enhances activity of the intermediates violently and the growth pace of sol clusters, influencing mostly and even violating the sol stability and the configurations of sol clusters and aggregates. The more over 2 added water ratio is, the more violent the stem chain branches, sol system precipitates in five minute at added water ratio of 3. in such case, the growth model of sol clusters changes completely. As the same mechanism as the water addition, the radical ions of acids and ammonia catalyze and accelerate hydrolysis and condensation reactions in sol process. For the introduction of strong electron donors (Lewis strong base) such as F-ions, the sol aggregates precipitate in five minute.
The Growth Process of Aggregates during Sol→Gel It has been shown from the surveys of small angle x-ray scattering(SAXS) and dynamic light scattering(DS) that monomers condense into primitive sol clusters by hydrolysis and coalescence at initial stage, when the clusters build up to a certain critical size of Rc≈8nm, clusters contact each other and cease to grow. These primitive clusters exist in sol solution though sol-gel process before gelling and after gelling.
Sol clusters neighboring each other joint into a hierarchy of sol aggregates abiding by self-similar construction as the initial clusters contact each other, whose sizes list in order: Rc,R2,R3,R4,R5R6,R7..., the size of later generation is larger a constant times than that of last generation, depending on the specific way smaller aggregates build up larger aggregates. Hierarchy of sol aggregates constructs itself from primitive clusters across macro-size aggregates up to gelling, the configuration manner of any generation is similar to that of other generation, only different from their sizes. In the case of SnO2 sol system, DS surveys demonstrate the existence of a hierarchy of five generations of sol aggregates with Rn/Rn-1≈4-6.
Near gelling, the hierarchy of sol aggregates coalesce raptly into infinite large aggregates of macroscopic size by jointing neighboringly and self-similarly bond-linking style, and sol system undergoes sol→gel transition into gelling bulk. Upon gelling bond-linkings take place principally among large aggregates, and the way aggregates coalesce change with respect to sol growth process, following percolation-linkage with fractal dimension D= 2.5, aggregates coalesce into space wetworks, average size Rz of sol aggregates tends to diverge as follows Rz∝(|1-t/tg|)-v.sol→gel transition belongs to a critical transition of percolation.
As sol-gel route proceeds, the survivals of monomers in solution attack the surface of sol primitive aggregates, and condense onto it, its surface tends smooth and surficial dimension approach to 2.0. At the same time, the primitive clusters diffuse ceaselessly in solution, and diffuse onto the surfaces and percolate into interiors of large aggregates, derive them to reconstruct, thus the surfaces of large aggregates become smooth gradually. However, the reconstruction of small and large aggregates can also attribute to slow aggregation style, and contribute to the exponential growth of sol aggregates with aging time.
Fractal configurations of sol aggregates The experimental data of dynamical relations of intrinsic viscosity of sol solutions with aging time [η]-t is in good agree with Flory-Bechtold's quasi-linear chain model ln[η]=(lnA+αlnΩ)+a ln[x/(1-x)] (x =t/tg),which verifys the proposal that the sol aggregates of SnO2 sol system belong to quasi-linear polymer chains. The fractal dimensions of such aggregates of linear chain are approximately 1.8, intervening between self-avoid random walk chain (SAW, D=5/3) and Guassian random walk chain(D=2.0). The fractal configurations and dimensions of SnO2 sol aggregates may be controlled by an adequate control of incorporation of water and catalysts. Before gelling, both primitive clusters formed in early stage by monomer reactions and hierarchy of aggregates constituted in later stage, keep the same fractal configuration though whole sol-gelling process.
Slow Aggregation Growth Model (Exponential Growth) The sol aggregates in SnO2 sol solution build up in style of the well-known slow aggregation before gelling. The experimental surveys show that shear viscosityηof sol solution satisfies the law of exponential variations with aging time:η∝exp[λ't], that is, Lnη-t keeps linear relation, the average sizes of sol aggregates meet exponential relation with aging time t:Rz～eλt. In quite later stage, sol growth transits into gelling style of bond-linking percolation. The existence of hierarchy of aggregates confirms that the growth of sol aggregates is controlled by Oswald Ripening mechanism (small cluster—large cluster aggregation) and diffusion limited cluster aggregation(DLCA) growth model,whose fractal dimension of aggregates is approximately 1.8.
Characterization Method Rheological dynamic measure may be used to characterize in situ the growth process of sol aggregates with availability and rapidity for liquid sol systems. The shear viscosityη, and intrinsic viscosity [η] are related to average size Rz and mass M of sol aggregates, rheological dynamic measures describe size and mass dynamical variations of sol aggregates with sol—gel process:Rz-t, M-t. Rheological dynamic characterization method, combining with dynamic light scattering (DS) developed recent years and other light scattering techniques, and under the theoretical frame of growth of molecule reaction/aggregation, may provides a lots of profound information of dynamics and structures related to geometrical configuration, growth mechanisms, fractal structure, growth mechanism of sol aggregates.
Two novel research results have been developed in the thesis. Firstly, a film-coating processing method for large scale production of heavy doped SnO2 coated glasses with low loss, Sol—Gel processing derived from alkyoxide, is developed up, in which sol coating solutions keep stable over 1000h with process working model being setup, prepared TCO films have excellent performance suit for efficient building windows. The second original result is introduction of a characterization method for liquid sol solution, Rheological Measuring method, which may be employed for aggregates of sol solutions to measure dynamic variations of average size Rz and mass M with time:Rz-t, M-t, and can acquire dynamical information in deep insight. Its setup is simple and measure is easily operated, has practical availability for on-line testing. Combining with light scattering measure means, Rheological Measuring method is a good measure mean of characterization of growth and structures of sol aggregates with self-similarity for liquid sol solutions.
引文
[1]Matthias Batzill, Ulrike Diebold, Review of the surface and materials science of tin oxide Progress in Surface Science 79 (2005) 47-154
[2]D.S. Jinley, C. Bright, Transparent conducting oxides,MRS Bull.25(8)(2000) 15
[3]T. Ninami, New n-type transparent conducting oxides, MRS Bull.25(8)(2000)38
[4]H. Kawazoe,H. Yanagi, K.Ueda,H. Hosono, MRS Bull.25(8)(2000) 28
[5]郭玉忠,王剑华,黄瑞安,掺杂Sn02透明带电薄膜电学及光学性能研究,无机材料学报,17(1)(2002)131-138
[6]Z.M. Jarzebski,J.P. Maton,Physical properties of SnO2 materials,(Ⅱ) Electrical Properties, J. Electrochem. Soc.123(9)(1976)299-310C
[7]ibid and idem., Physical properties of SnO2 materials,(Ⅲ)Optical properties, 123(10)(1976)333-346C
[8]B. Thiel, R. Helbig, Growth of SnO2 single crystals by a vapor phase reaction method,J. Cryst. Growth 32 (1976) 259.
[9]I. Hamberg, C.G. Granqvist, Evaporated Sn-doped In2O3 films:basic optical properties and applications to energy-efficient windows, J. Appl. Phys.60 (1986) R123.
[10]C.G. Granqvist, A. Hulta°ker, Transparent and conducting ITO films:new developments and applications, Thin Solid Films 411 (2002) 1-5
[11]W. Gospel,K. D. Schierbaum,SnO2 sensors:current status and future prospects, Sensors And Actuators 26-27B(1995)1-12
[12]P.G. Harrison, Tin(Ⅳ)oxide:surface chemistry, catalysis and gas sensing, in:P.G. Harrison (Ed.), Chemistry of Tin, Blackie, Glasgow,1989.
[13]P. R. Bueno, J. A. Varela, E. Longo, Review of SnO2, ZnO and related polycrystallinecompound semiconductors:An overview and review on the voltage-dependent resistance (non-ohmic) feature, J. Europ. Ceram. Soc 28 (2008) 505-529
[14]李俊清,量子化学中Xα方法及其应用,102个元素轨道能量表,安徽科学技术出版社,1983
[15]A. Svane,E. Andoncik Electronic structure of rutile SnO2,GeO2,TeO2, J. Phys. Chem. Solids,48(2)(1987) 171-180
[16]C. Kilic, A. Zunger, Origins of coexistence of conductivity and transparency in SnO2, Phys. Rev. Lett.88 (9)(2002) 5501
[17]J.A. M.arley, R.C. Dockerty, Electrical properties of stannic oxide single crystals, Phys. Rev.140 (1965) A304.
[18]Y. Mizokawa, S. Nakamura, ESR and electric conductance studies of the fine-powdered SnO2, Jpn. J. Appl. Phys.14 (1975) 779
[19]N. F.Mott,Metal-insulator transition,Rev. Modern Phys.40(4)(1968)677-683
[20]H. F. Hess,K. Deconde T.F. Rosenbaum,G.A. Thomas, Phys. Rev. B25(1982) 5578
[21]K.C. Mishra, K.H. Johnson, P.C. Schmidt, Electronic-structure of antimony doped tin oxide,Phys. Rev. B51 (1995) 13972.
[22]O.N. Mryasov, A.J. Freeman, Electronic band structure of indium tin oxide and criteria for transparent conducting behaviour, Phys. Rev. B 64 (2001) 233111
[23]A.J. Freean,E. Wimmer, Density functional theory as major tool in computational Materials science, Annu. Rev. Mater. Sci.25(1995)7-36
[24]E. Burstein, Anomalous optical absorption limit in InSb, Phys. Rev.93 (1954) 632
[25]K. Ellmer, Resistivity of polycrystalline zinc oxide films:current status and physical Limit J.Phys. D:Appl. Phys.34 (2001) 3097-3108
[26]R. B. Dingle, The purity ion scattering of electrons in semiconductors with Screened Coulombian potentials, Phli. Mag.46(1955)831
[27]G Thomas, Nature,389(1997)907
[28]Kenji Nomura, Hiromichi Ohta,Kazushige Ueda,Toshio Kamiya,Masahiro Hirano, HideoHosono, Science.300(2003)1268-1272
[29]J. F. Wager,Transparent electronics, Science.300 (2003) 1245-6
[30]Jia Grace Lu, Paichun Chang, Zhiyong Fan, Quasi-one-dimensional metal oxide materials-Synthesis, properties and applications, Mater. Sci. Eng. R 52 (2006) 49-91
[31]Z.R. Dai, Z.W. Pan, Z.L. Wang, Novel nanostructures of functional oxides synthesized by thermal evaporation, Adv. Funct. Mater.13 (2003) 9.
[32]Z.R. Dai, Z. Wei Pan, Z.L. Wang, Growth and structure evolution of novel tin oxide diskettes, J. Am. Chem. Soc.124 (2002) 8673.
[33]Z.R. Dai, Z.W. Pan, Z.L. Wang, Ultra-long single crystalline nanoribbons of tin oxide, Solid State Commun.118 (2001) 351.
[34]Z.W. Pan, Z.R. Dai, Z.L. Wang, Nanobelts of semiconducting oxides, Science 291 (2001)1947.
[35]Z.L. Wang, Functional oxide nanobelts:materials, properties and potential applications in Nanosystems and biotechnology, Annu. Rev. Phys. Chem.55 (2004) 159.
[36]A. Beltra'n, J. Andre's, E. Longo, E.R. Leite, Thermodynamic argument about SnO2 nanoribbon growth, Appl. Phys. Lett.83 (2003) 635.
[37]Z.R. Dai, J.L. Gole, J.D. Stout, Z.L. Wang, Tin oxide nanowires, nanoribbons, and Nano-tubes, J. Phys. Chem. B 106 (2002) 1274
[38]Z.L. Wang, Nanobelts, nanowires, and nanodiskettes of semiconducting oxides—from materials to nanodevices, Adv. Mater.15 (2003) 432.
[39]J.Q. Hu, Y. Bando, D. Goldberg, Self-catalyst growth and optical properties of novel SnO2 fishbone-like nanoribbons, Chem. Phys. Lett.372 (2003) 758.
[40]N.S. Ramgir, I.S. Mulla, K.P. Vijayamohanan, Shape selective synthesis of unusal nanobipyramids, cubes, and nanowires of RuO2:SnO2, J. Phys. Chem. B 108 (2004) 14815.
[41]E.R. Leite, J.W. Gomes, M.M. Oliviera, E.J.H. Lee, E. Longo, J.A. Varela, C.A. Paskocimas, T.M. Boschi, F. Lanciotti Jr., P.S. Pizani, P.C. Soares Jr., Synthesis of nanoribbons by a carbothermal reduction process, J. Nanosci. Nanotech.2 (2002) 125.
[42]J.X. Wang, D.F. Liu, X.Q. Yan, H.J. Yuan, L.J. Ci, Z.P. Zhou, Y. Gao, L. Song, L.F. Liu, W.Y. Zhou, G. Wang, S.S. Xie, Growth of SnO2 nanowires with uniformbranched structures, Solid State Commun.130 (2004) 89.
[43]J. Hu, Y. Bando, Q. Liu, D. Goldberg, Laser-ablation growth and optical properties of wide and long single-crystal SnO2 ribbons, Adv. Funct. Mater.13 (2003) 493.
[44]C. Ye, X. Fang, Y. Wang, T. Xie, A. Zhao, L. Zhang, Novel synthesis of tin dioxide nanoribbons via a mild solution approach, Chem. Lett.33 (2004) 54.
[45]C.-F. Wang, S.-Y. Xie, S.-C. Lin, X. Cheng, X.H. Zhang, R.-B. Huang, L.S. Zheng, Glow discharge growth of SnO2 nano-needles from SnH4, Chem. Commun. (2004) 1766.
[46]Y. Liu, J. Dong, M. Liu, Well-aligned_nano-box-beams_ of SnO2, Adv. Mater.16 (2004)353.
[47]Y. Wang, J.Y. Lee, T.C. Deivaraj, Controlled synthesis of V-shaped SnO2 nanorods,J. Phys. Chem. B 108 (2004) 13589.
[48]T.G.G. Maffei″s, G.T. Owen, M.W. Penny, T.K.H. Starke, S.A. Clark, H. Ferkel, S.P. Wilks, Nanocrystalline SnO2 gas sensor response to 02 and CH4 at elevated temperature investigated by XPS, Surf. Sci.520 (2002) 29.
[49]B. Cheng, J.M. Russell, W. Shi, L. Zhang, E.T. Samulski, Large-scale, solution-phase growth of single crystalline SnO2 nanorods, J. Am. Chem. Soc.126 (2004) 5972.
[50]E. Comini, G. Faglia, G. Sberveglieri, Z. Pan, Z.L. Wang, Stable and highly sensitive gas sensors based on semiconductingoxide nanobelts, Appl. Phys. Lett.81 (2002) 1869.
[51]A. Maiti, Electromechanical and chemical sensingat he nanoscale:Molecular modeling applications, Mol. Simul.30 (2004) 191.
[52]E. Comini, V. Guidi, C. Malaga, G. Martinelli, Z. Pan, G.-S. Sberveglieri, Z.L. Wang, Electrical properties of tin dioxide two-dimensional nanostructures, J. Phys. Chem. B 108(2004) 1882.
[53]S.T. Shishiyanu, T.S. Shishiyanu, O.I. Lupan, Sensing characteristics of tin-doped ZnO thin films as NO2 gas sensor, Sens. Actuators B Chem.107 (2005) 379.
[54]Z.Y. Fan, J.G. Lu, Gate-refreshable nanowire chemical sensors, Appl. Phys. Lett.86 (2005) 123510.
[55]A. Kolmakov, M. Moskovits, Chemical sensing and catalysis by one-dimensional metal-oxide nanostructures, Annu. Rev. Mater. Res.34 (2004) 151.
[56]A. Kolmakov, M. Moskovits, Chemical sensing and catalysis by one-dimensional, metal-oxide nanostructures, Annu. Rev. Mater. Res.34 (2004) 151.
[57]S.Arulkumaran et al,Appl. Phys. Lett.,81(2002)1131
[58]S.Harada et al,Mater. Sci. Forum 389-393(2002)1069
[59]H. Kawazoe, M. Yasukawa, H. Hyodo, M. Kurita, H. Yanagi, and H. Hosono, Nature (London) 389 (1997) 939.
[60]A. Kudo, H. Yanagi, K. Ueda, H. Hosono, and H. Kawazoe, Appl. Phys. Lett. 75(1999),2851
[61]H. Yanagi, K. Ueda, H. Ohta, M. Orita, M. Hirano, and H. Hosono, Solid State Commun.121(2001) 15
[62]H. Ohta, K. Kawamura, M. Orita, M. Hirano, N. Sarukura, and H. Hosono, Appl. Phys. Lett.77(2000) 475.
[63]Y. Matsumoto, M. Murakami, T. Shono, T. Hasegawa, T. Fukumura, M. Kawasaki, P.Ahmet, T. Chikyow, S. Koshihara, and H. Koinuma, Science 291(2001) 854.
[64]M. L. Reed, M. K. Ritums, H. H. Stadelmaier, M. J. Reed, C. A. Parker, S. M. Bedair, and N. A. El-Masry, Mater. Lett.51(2001) 500
[65]R. L. Hoffman, B. J. Norris,J. F. Wager, App. Phys. Lett.,82(5)(2003)733
[66]H. A. Klasens, H. Koelmans Solid-State Electron.77(1964)1-2
[67]A. Aoki, H. Sasakura, Japan. J. Appl. Phys.9(1970) 582
[68]M. W. J. Prins, K-O. Grosse-Holz, G. Muller, J F. M. Cillessen, J. B. Giesbers, R. P. Weening, R. M. Wolf, Appl. Phys. Lett.68 (1996)3650-2
[69]M. W. J. Prins, S. E. Zinnemers, J. F M. Cillessen, J. B. Giesbers Appl. Phys. Lett.70 (1997)458-60
[70]J. Wollenstein, M. Jagle, H. Bottner 2003,Advanced Gas Sensing ed T Doll (Boston: Kluwer Academic), pp 85-99
[71]R. E. Presley, C. L. Munsee, C-H Park, D. Hong, J. F. Wager, D. A. Keszler, Tin oxide transparent thin-film transistors, J. Phys. D:Appl. Phys.37 (2004) 2810-2813
[72]Satoshi Masuda, Ken Kitamura, Yoshihiro Okumura, and Shigehiro Miyatake, Hitoshi Tabata Tomoji Kawai, J. App. Phys.,93(31)(2003)1624
[73]P. F. Carcia, R. S. McLean, M. H. Reily, G. Nunes 2003 Appl. Phys. Lett.821117-19
[74]Jong Hoon Kim, Byung Du Ahn, Choong Hee Lee, Kyung Ah Jeon, Hong Seong Kang, Sang Yeol Lee, Thin Solid Films 516 (2008) 1529-1532
[75]H.T. Ng, J. Han, T. Yamada, P. Nguyen, Y.P. Chen, M. Meyyappan, Single crystal nanowire vertical surround-gatefield-effect transistor, Nano Lett.4 (2004) 1247.
[76]M.J. Fuller, M.E. Warwick, The catalytic oxidation of carbon monoxide on tin(IV)oxide, J.Catal.29 (1973) 441.
[77]M. J. Fuller, M.E. Warwick, The catalytic oxidation of carbon monoxide on SnO2-CuO gels, J. Catal.34 (1974) 445.
[78]G.C. Bond, L.R. Molloy,M.J. Fuller, Oxidation of carbon monoxide over palladium-tin(IV) oxide catalysts:an example of spillover catalysis, J. Chem. Soc. Chem. Commun. (1975) 796.
[79]G. Croft, M.J. Fuller, Water-promoted oxidation of carbon monoxide over tin(Ⅳ) oxide-Supported palladium, Nature 269 (1977) 585.
[80]M.J. Fuller, M.E. Warwick, The catalytic reduction of nitric oxide by carbon monoxide over SnO2-CuO gels, J. Catal.42 (1976) 418.
[81]F. Solymosi, J. Kiss, Adsorption and reduction of NO on tin(Ⅳ) oxide doped with chromium(Ⅲ) oxide, J. Catal.54 (1978) 42.
[82]P.G. Harrison, C. Bailey, W. Azelee, Modified tin(Ⅳ) oxide (M/SnO2 M=Cr, LA, Pr, Nd, Sm, Gd) catalysts for oxidation of carbon monoxide and propane, J. Catal.186 (1999) 147.
[83]P.W. Park, H.H. Kung, D.-W. Kim, M.C. Kung, Characterization of SnO2/Al2O3 lean NOx catalysts, J. Catal.184 (1999) 440.
[84]P.G. Harrison, in:P.G. Harrison (Ed.), Chemistry of Tin, Blackie, Glasgow,1989 (Chapter 12).
[85]K. Sekizawa, H. Widjaja, S. Maeda, Y. Ozawa, K. Eguchi, Low temperature oxidation of methane over Pd/SnO2 catalyst, Appl. Catal. A 200 (2000) 211.
[86]H. Widjaja, K. Sekizawa, K. Eguchi, Low-temperature oxidation of methane over Pd supported on SnO2-based oxides, Bull. Chem. Soc. Jpn.72 (1999) 313.
[87]T. Takeguchi, O. Takeoh, S. Aoyama, J. Ueda, R. Kikuchi, K. Eguchi, Strong chemical interaction between PdO and SnO2 and the influence on catalytic combustion of methane, Appl. Catal. A 252 (2003) 205.
[88]P.G. Harrison, N.C. Lloyd, W. Daniell, The nature of the chromium species formed duringthe thermal activation of chromium-promoted tin(Ⅳ) oxide catalysts:an EPR and XPS study, J. Phys. Chem. B 102 (1998) 10672.
[89]P.G. Harrison, N.C. Lloyd, W. Daniell, C. Bailey, W. Azelee, Evolution of microstructureDuringthermal activation of chromium-promoted tin(Ⅳ) oxide catalysts:an FT-IR, FT-Raman, XRD, TEM and XANES/EXAFS study, Chem. Mater.11(1999)896.
[90]P.G. Harrison, W. Azelee, A.T. Mubarak, C. Bailey, W. Daniell, N.C. Lloyd, in:N. Kruse, A. Frennet, J.-M. Bastin (Eds.), Catalysis and Automotive Pollution Control. IV, Studies in Surface Science and Catalysis, vol.116, Elsevier, Amsterdam,1988.
[91]G. Centi, F. Trifiro', Oxidation catalysts based on antimony mixed oxides with rutile-type structures, Catal. Rev.28 (1986) 165.
[92]F.J. Berry, Tin-antimony oxide catalysts, Adv. Catal.30 (1981) 97.
[93]H.J. Herniman, D.R. Pyke, R. Reid, An investigation of the relationship between the bulk and surface composition of tin and antimony mixed oxide catalysts and the oxidative dehydrogenation of 1-butene to butadiene, J. Catal.58 (1979) 68.
[94]Y.M. Cross, D.R. Pyke, An X-ray photoelectron spectroscopy study of the surface composition of tin and antimony mixed metal oxide catalysts, J. Catal.58 (1979) 61.
[95]Y. Boudeville, F. Figueras, M. Forissier, J.L. Portefaix, J.C. Vedrine, Correlations between X-ray photoelectron spectroscopy data and catalytic properties in selective oxidation on Sb-Sn-O catalysts, J. Catal.58 (1979) 52.
[96]F. Sala, F. Trifiro', Oxidation catalysts based on tin-antimony oxides, J. Catal.34 (1974)68.
[97]N.G. Valente, L.E. Cadu's, O.F. Gorriz, L.A. Arru'a, J.B. Rivarola, Synergy in Sn-Mo-O catalysts:the selective oxidation of methanol, Appl. Catal. A 153 (1997) 119.
[98]L.J. Lakshmi, E.C. Alyea, ESR, FT-Raman spectroscopic and ethanol partial oxidation studies on MoO3/SnO2 catalysts made by metal oxide vapor synthesis, Catal. Lett.59 (1999)73.
[99]M. Niwa, H. Yamada, Y. Murakami, Activity for the oxidation of methanol of a molybdena monolayer supported on tin oxide, J. Catal.134 (1992) 331.
[100]T. Ono, H. Kamisuki, H. Hisashi, H. Miyata, A comparison of oxidation activities and structures of Mo oxides highly dispersed on group IV oxide supports, J. Catal. 116(1989)303.
[101]M. Daturi, L.G. Appel, Infrared spectroscopic studies of surface properties of Mo/SnO2 catalyst, J. Catal.209 (2002) 427.
[102]M. Niwa, M. Mizutani, M. Takahashi, Y. Murakami, Mechanism of methanol oxidation over oxide catalysts containingMoO3, J. Catal.70 (1981)14.
[103]R. Skolmeistere, L. Leitis, M. Shymanska, J. Stoch, Influence of preparation conditions on activity andphysical properties of V2O5-SnO2 catalyst for oxidative destruction of residual pyridine bases, Catal. Today 17 (1993) 79.
[104]S.L.T. Andersson, S. Jaras, Activity measurements and ESCA investigations of a V2O5/SnO2 catalyst for the vapor-phase oxidation of alkylpyridines, J. Catal.64 (1980)51.
[105]S. Bordoni, F. Catellani, F. Cavani, F. Trifiro', M. Gazzano, Nature of vanadium species in SnO2-V2O5-based catalysts. Chemistry of preparation, characterization, thermal stability and reactivity in ethane oxidative dehydrogenation over V-Sn mixed oxides, J. Chem. Soc. Faraday Trans.90 (1994) 2981.
[106]P.G. Harrison, Tin(Ⅳ)oxide:surface chemistry, catalysis and gas sensing, in:P.G. Harrison (Ed.), Chemistry of Tin, Blackie, Glasgow,1989.
[107]P. Aigrain, C. Dugas, Adsorption sur les semi-conducteurs, Z. Elektrochem.56 (1952) 363.
[108]P.B. Weisz, Electronic barrier layer phenomena in chemisorption and catalysis, J. Chem.Phys.20 (1952) 1483.
[109]K. Hauffe, H.J. Engel, Zum Mechanismus der Chemisorption vom Standpunkt der Fehlordnungstheorie, Z. Elektrochem.56 (1952) 366.
[110]K. Hauffe, The application of the theory of semiconductors to problems of heterogenous catalysis, Adv. Catal.7 (1955) 213.
[111]Th. Wolkenstein, Sur les differents types de liaisons lors de L_adsorption chimique sur dessemi-conducteurs, Adv. Catal.9 (1957) 807.
[112]Th. Wolkenstein, Sur le mecanisme de 1_action catalytique des semi-conducteurs, Adv. Catal.9(1957)818.
[113]J. Haber, M. Witko, Oxidation catalysis-electronic theory revisited, J. Catal.216 (2003)416.
[114]J. E. Martin,D. Adolf,The sol-gel transition in chemical gels,Annu. Rev. Phys. Chem.42(1991)311-339
[115]郭玉忠,黄瑞安,孙加林,Sn02溶胶系水解缩合实验研究,硅酸盐学报,29(2)(2001)157-162
[116]Naichao Li, Charles R. Martin, A High Rate, High Capacity, Nanostructured Sn-based Anode Prepared Using Sol-Gel Template Synthesis, J. Electrochem. Soc.148(2)A (2001)164-170
[117]C. B. Murray, C. R. Kagan, M. G. Bawendi, Synthesis and characterization of mono-disperse nano-Crystals and close-packed nanocrystal assemblies, Annu. Rev. Mater. Sci.30(2000)545-610
[118]R.Pecora,Dynamic Light Scattering,New York, Plenum Press,1985,p7-301.
[119]郭玉忠,黄瑞安,王剑华,Sn02溶胶-凝胶转变的流变学研究,无机材料学报,16(2)(2001)249-255
[120]S.Schiller,G. Beister, M. Numann, G. Jaesch, Vacuum coating of large areas, Thin Solid Films.96(1982)199-216
[121]R. Kalbskopf, Continuous chemical vapor deposition of tin oxide, Thin Solid Films.77(1981)65-66
[122]N. Jackson, J. Ford Experience in the control and evaluation of coatings on glass containers, Thin Solid Films.77(1981)23-39
[123]M.F.Bechtold, Silicic acid from tetraethyl silicate hydrolysis polymerization and properties, J. Am. Chem Soc,90 (1968) 4590-4598
[124]Laine. R.M. Chemical processing of glasses, In:. Mackenzie. J. D, Ulrich. D. R, eds.Sol-Gel Optics, San Diego, SPIE,1990,1328:96-301
[125]E.T. A Pope., J.D Mackenzie,Role of catalysts in silica sol-gel route. J.Non-cryst. Solids,1986,87(1968)185-196
[126]P.J. Flory et al,J. Am. Chem. Soc.,73(1951):1904-1908
[127]J.E.Martin,slow aggregation of colloidal silica, Phys. Rev.,36A (7) (1987) 3415-26
[128]Ruian Huang, Yuzong Guo,Formation and characterization of tin oxide aerogel derived from sol-gel process based on Tetra(n-butoxy) tin(Ⅳ), J. noncrystalline solids,2005,351(1):23-38
[129]张济忠,分形,p 104-347,清华大学出版社,1995
[130]P. G. J. Van Dongen, M. H.Ernst,Dynamics scaling in kinetics of clustering, Phys. Rev. Lett.54(13)(1985)1396-1399
[131]J.E.Martin, J.Wilcoxon,D.Adolf, Critical Exponents for the Sol-Gel Transition, Phys. Rev..36 A[4] (1987) 1803-10
[132]M.Daoud,J.E.Martin,1989, The Fractal Approach to Heterogeneous Chemistry, ed. D.Avnir, pp.109-130, New York:Wiley.
[133]J.E.Martin,J.P.Wilcoxon,D.Schaefer,et al,Fast aggregation of colloidal silica, Phys. Rev.,41A (8) (1990) 4379-91
[134]C.J.Brinker, G.W.Sherer, J. Non-Cryst. Solids,72 (1985) 345
[135]G. Frank, E. Kauer,H. Kostlin, Transparent heat-reflecting coatings based highly doped emiconductors,Thin Solid Films.77(1981)107-117
[136]王剑华,孙加林,Sn02凝胶干燥及固化过程中的结构变化,无机材料学报,16(3)(2001)410-418.
[137]K.Seeger,半导体物理学,徐乐,钱建业译,人民教育出版社,1980,P57-102,392-498.
[138]MNagasawa, S Shionoya, Phys. Lett.,1966,22(1966)409-414.
[139]N F Mott,Rev. Mod. Phys.,40(10)(1966)677-683.
[140]N F Mott,Advan.Phys., Electrons in disordered structures,16(1967)49-144
[141]C. G. Granqvist, Radiative heating and cooling with spectrally selective surfaces, Applied Optics.20(15)(1981)2606-2615
[2]D.S. Jinley, C. Bright, Transparent conducting oxides,MRS Bull.25(8)(2000) 15
[3]T. Ninami, New n-type transparent conducting oxides, MRS Bull.25(8)(2000)38
[4]H. Kawazoe,H. Yanagi, K.Ueda,H. Hosono, MRS Bull.25(8)(2000) 28
[5]郭玉忠,王剑华,黄瑞安,掺杂Sn02透明带电薄膜电学及光学性能研究,无机材料学报,17(1)(2002)131-138
[6]Z.M. Jarzebski,J.P. Maton,Physical properties of SnO2 materials,(Ⅱ) Electrical Properties, J. Electrochem. Soc.123(9)(1976)299-310C
[7]ibid and idem., Physical properties of SnO2 materials,(Ⅲ)Optical properties, 123(10)(1976)333-346C
[8]B. Thiel, R. Helbig, Growth of SnO2 single crystals by a vapor phase reaction method,J. Cryst. Growth 32 (1976) 259.
[9]I. Hamberg, C.G. Granqvist, Evaporated Sn-doped In2O3 films:basic optical properties and applications to energy-efficient windows, J. Appl. Phys.60 (1986) R123.
[10]C.G. Granqvist, A. Hulta°ker, Transparent and conducting ITO films:new developments and applications, Thin Solid Films 411 (2002) 1-5
[11]W. Gospel,K. D. Schierbaum,SnO2 sensors:current status and future prospects, Sensors And Actuators 26-27B(1995)1-12
[12]P.G. Harrison, Tin(Ⅳ)oxide:surface chemistry, catalysis and gas sensing, in:P.G. Harrison (Ed.), Chemistry of Tin, Blackie, Glasgow,1989.
[13]P. R. Bueno, J. A. Varela, E. Longo, Review of SnO2, ZnO and related polycrystallinecompound semiconductors:An overview and review on the voltage-dependent resistance (non-ohmic) feature, J. Europ. Ceram. Soc 28 (2008) 505-529
[14]李俊清,量子化学中Xα方法及其应用,102个元素轨道能量表,安徽科学技术出版社,1983
[15]A. Svane,E. Andoncik Electronic structure of rutile SnO2,GeO2,TeO2, J. Phys. Chem. Solids,48(2)(1987) 171-180
[16]C. Kilic, A. Zunger, Origins of coexistence of conductivity and transparency in SnO2, Phys. Rev. Lett.88 (9)(2002) 5501
[17]J.A. M.arley, R.C. Dockerty, Electrical properties of stannic oxide single crystals, Phys. Rev.140 (1965) A304.
[18]Y. Mizokawa, S. Nakamura, ESR and electric conductance studies of the fine-powdered SnO2, Jpn. J. Appl. Phys.14 (1975) 779
[19]N. F.Mott,Metal-insulator transition,Rev. Modern Phys.40(4)(1968)677-683
[20]H. F. Hess,K. Deconde T.F. Rosenbaum,G.A. Thomas, Phys. Rev. B25(1982) 5578
[21]K.C. Mishra, K.H. Johnson, P.C. Schmidt, Electronic-structure of antimony doped tin oxide,Phys. Rev. B51 (1995) 13972.
[22]O.N. Mryasov, A.J. Freeman, Electronic band structure of indium tin oxide and criteria for transparent conducting behaviour, Phys. Rev. B 64 (2001) 233111
[23]A.J. Freean,E. Wimmer, Density functional theory as major tool in computational Materials science, Annu. Rev. Mater. Sci.25(1995)7-36
[24]E. Burstein, Anomalous optical absorption limit in InSb, Phys. Rev.93 (1954) 632
[25]K. Ellmer, Resistivity of polycrystalline zinc oxide films:current status and physical Limit J.Phys. D:Appl. Phys.34 (2001) 3097-3108
[26]R. B. Dingle, The purity ion scattering of electrons in semiconductors with Screened Coulombian potentials, Phli. Mag.46(1955)831
[27]G Thomas, Nature,389(1997)907
[28]Kenji Nomura, Hiromichi Ohta,Kazushige Ueda,Toshio Kamiya,Masahiro Hirano, HideoHosono, Science.300(2003)1268-1272
[29]J. F. Wager,Transparent electronics, Science.300 (2003) 1245-6
[30]Jia Grace Lu, Paichun Chang, Zhiyong Fan, Quasi-one-dimensional metal oxide materials-Synthesis, properties and applications, Mater. Sci. Eng. R 52 (2006) 49-91
[31]Z.R. Dai, Z.W. Pan, Z.L. Wang, Novel nanostructures of functional oxides synthesized by thermal evaporation, Adv. Funct. Mater.13 (2003) 9.
[32]Z.R. Dai, Z. Wei Pan, Z.L. Wang, Growth and structure evolution of novel tin oxide diskettes, J. Am. Chem. Soc.124 (2002) 8673.
[33]Z.R. Dai, Z.W. Pan, Z.L. Wang, Ultra-long single crystalline nanoribbons of tin oxide, Solid State Commun.118 (2001) 351.
[34]Z.W. Pan, Z.R. Dai, Z.L. Wang, Nanobelts of semiconducting oxides, Science 291 (2001)1947.
[35]Z.L. Wang, Functional oxide nanobelts:materials, properties and potential applications in Nanosystems and biotechnology, Annu. Rev. Phys. Chem.55 (2004) 159.
[36]A. Beltra'n, J. Andre's, E. Longo, E.R. Leite, Thermodynamic argument about SnO2 nanoribbon growth, Appl. Phys. Lett.83 (2003) 635.
[37]Z.R. Dai, J.L. Gole, J.D. Stout, Z.L. Wang, Tin oxide nanowires, nanoribbons, and Nano-tubes, J. Phys. Chem. B 106 (2002) 1274
[38]Z.L. Wang, Nanobelts, nanowires, and nanodiskettes of semiconducting oxides—from materials to nanodevices, Adv. Mater.15 (2003) 432.
[39]J.Q. Hu, Y. Bando, D. Goldberg, Self-catalyst growth and optical properties of novel SnO2 fishbone-like nanoribbons, Chem. Phys. Lett.372 (2003) 758.
[40]N.S. Ramgir, I.S. Mulla, K.P. Vijayamohanan, Shape selective synthesis of unusal nanobipyramids, cubes, and nanowires of RuO2:SnO2, J. Phys. Chem. B 108 (2004) 14815.
[41]E.R. Leite, J.W. Gomes, M.M. Oliviera, E.J.H. Lee, E. Longo, J.A. Varela, C.A. Paskocimas, T.M. Boschi, F. Lanciotti Jr., P.S. Pizani, P.C. Soares Jr., Synthesis of nanoribbons by a carbothermal reduction process, J. Nanosci. Nanotech.2 (2002) 125.
[42]J.X. Wang, D.F. Liu, X.Q. Yan, H.J. Yuan, L.J. Ci, Z.P. Zhou, Y. Gao, L. Song, L.F. Liu, W.Y. Zhou, G. Wang, S.S. Xie, Growth of SnO2 nanowires with uniformbranched structures, Solid State Commun.130 (2004) 89.
[43]J. Hu, Y. Bando, Q. Liu, D. Goldberg, Laser-ablation growth and optical properties of wide and long single-crystal SnO2 ribbons, Adv. Funct. Mater.13 (2003) 493.
[44]C. Ye, X. Fang, Y. Wang, T. Xie, A. Zhao, L. Zhang, Novel synthesis of tin dioxide nanoribbons via a mild solution approach, Chem. Lett.33 (2004) 54.
[45]C.-F. Wang, S.-Y. Xie, S.-C. Lin, X. Cheng, X.H. Zhang, R.-B. Huang, L.S. Zheng, Glow discharge growth of SnO2 nano-needles from SnH4, Chem. Commun. (2004) 1766.
[46]Y. Liu, J. Dong, M. Liu, Well-aligned_nano-box-beams_ of SnO2, Adv. Mater.16 (2004)353.
[47]Y. Wang, J.Y. Lee, T.C. Deivaraj, Controlled synthesis of V-shaped SnO2 nanorods,J. Phys. Chem. B 108 (2004) 13589.
[48]T.G.G. Maffei″s, G.T. Owen, M.W. Penny, T.K.H. Starke, S.A. Clark, H. Ferkel, S.P. Wilks, Nanocrystalline SnO2 gas sensor response to 02 and CH4 at elevated temperature investigated by XPS, Surf. Sci.520 (2002) 29.
[49]B. Cheng, J.M. Russell, W. Shi, L. Zhang, E.T. Samulski, Large-scale, solution-phase growth of single crystalline SnO2 nanorods, J. Am. Chem. Soc.126 (2004) 5972.
[50]E. Comini, G. Faglia, G. Sberveglieri, Z. Pan, Z.L. Wang, Stable and highly sensitive gas sensors based on semiconductingoxide nanobelts, Appl. Phys. Lett.81 (2002) 1869.
[51]A. Maiti, Electromechanical and chemical sensingat he nanoscale:Molecular modeling applications, Mol. Simul.30 (2004) 191.
[52]E. Comini, V. Guidi, C. Malaga, G. Martinelli, Z. Pan, G.-S. Sberveglieri, Z.L. Wang, Electrical properties of tin dioxide two-dimensional nanostructures, J. Phys. Chem. B 108(2004) 1882.
[53]S.T. Shishiyanu, T.S. Shishiyanu, O.I. Lupan, Sensing characteristics of tin-doped ZnO thin films as NO2 gas sensor, Sens. Actuators B Chem.107 (2005) 379.
[54]Z.Y. Fan, J.G. Lu, Gate-refreshable nanowire chemical sensors, Appl. Phys. Lett.86 (2005) 123510.
[55]A. Kolmakov, M. Moskovits, Chemical sensing and catalysis by one-dimensional metal-oxide nanostructures, Annu. Rev. Mater. Res.34 (2004) 151.
[56]A. Kolmakov, M. Moskovits, Chemical sensing and catalysis by one-dimensional, metal-oxide nanostructures, Annu. Rev. Mater. Res.34 (2004) 151.
[57]S.Arulkumaran et al,Appl. Phys. Lett.,81(2002)1131
[58]S.Harada et al,Mater. Sci. Forum 389-393(2002)1069
[59]H. Kawazoe, M. Yasukawa, H. Hyodo, M. Kurita, H. Yanagi, and H. Hosono, Nature (London) 389 (1997) 939.
[60]A. Kudo, H. Yanagi, K. Ueda, H. Hosono, and H. Kawazoe, Appl. Phys. Lett. 75(1999),2851
[61]H. Yanagi, K. Ueda, H. Ohta, M. Orita, M. Hirano, and H. Hosono, Solid State Commun.121(2001) 15
[62]H. Ohta, K. Kawamura, M. Orita, M. Hirano, N. Sarukura, and H. Hosono, Appl. Phys. Lett.77(2000) 475.
[63]Y. Matsumoto, M. Murakami, T. Shono, T. Hasegawa, T. Fukumura, M. Kawasaki, P.Ahmet, T. Chikyow, S. Koshihara, and H. Koinuma, Science 291(2001) 854.
[64]M. L. Reed, M. K. Ritums, H. H. Stadelmaier, M. J. Reed, C. A. Parker, S. M. Bedair, and N. A. El-Masry, Mater. Lett.51(2001) 500
[65]R. L. Hoffman, B. J. Norris,J. F. Wager, App. Phys. Lett.,82(5)(2003)733
[66]H. A. Klasens, H. Koelmans Solid-State Electron.77(1964)1-2
[67]A. Aoki, H. Sasakura, Japan. J. Appl. Phys.9(1970) 582
[68]M. W. J. Prins, K-O. Grosse-Holz, G. Muller, J F. M. Cillessen, J. B. Giesbers, R. P. Weening, R. M. Wolf, Appl. Phys. Lett.68 (1996)3650-2
[69]M. W. J. Prins, S. E. Zinnemers, J. F M. Cillessen, J. B. Giesbers Appl. Phys. Lett.70 (1997)458-60
[70]J. Wollenstein, M. Jagle, H. Bottner 2003,Advanced Gas Sensing ed T Doll (Boston: Kluwer Academic), pp 85-99
[71]R. E. Presley, C. L. Munsee, C-H Park, D. Hong, J. F. Wager, D. A. Keszler, Tin oxide transparent thin-film transistors, J. Phys. D:Appl. Phys.37 (2004) 2810-2813
[72]Satoshi Masuda, Ken Kitamura, Yoshihiro Okumura, and Shigehiro Miyatake, Hitoshi Tabata Tomoji Kawai, J. App. Phys.,93(31)(2003)1624
[73]P. F. Carcia, R. S. McLean, M. H. Reily, G. Nunes 2003 Appl. Phys. Lett.821117-19
[74]Jong Hoon Kim, Byung Du Ahn, Choong Hee Lee, Kyung Ah Jeon, Hong Seong Kang, Sang Yeol Lee, Thin Solid Films 516 (2008) 1529-1532
[75]H.T. Ng, J. Han, T. Yamada, P. Nguyen, Y.P. Chen, M. Meyyappan, Single crystal nanowire vertical surround-gatefield-effect transistor, Nano Lett.4 (2004) 1247.
[76]M.J. Fuller, M.E. Warwick, The catalytic oxidation of carbon monoxide on tin(IV)oxide, J.Catal.29 (1973) 441.
[77]M. J. Fuller, M.E. Warwick, The catalytic oxidation of carbon monoxide on SnO2-CuO gels, J. Catal.34 (1974) 445.
[78]G.C. Bond, L.R. Molloy,M.J. Fuller, Oxidation of carbon monoxide over palladium-tin(IV) oxide catalysts:an example of spillover catalysis, J. Chem. Soc. Chem. Commun. (1975) 796.
[79]G. Croft, M.J. Fuller, Water-promoted oxidation of carbon monoxide over tin(Ⅳ) oxide-Supported palladium, Nature 269 (1977) 585.
[80]M.J. Fuller, M.E. Warwick, The catalytic reduction of nitric oxide by carbon monoxide over SnO2-CuO gels, J. Catal.42 (1976) 418.
[81]F. Solymosi, J. Kiss, Adsorption and reduction of NO on tin(Ⅳ) oxide doped with chromium(Ⅲ) oxide, J. Catal.54 (1978) 42.
[82]P.G. Harrison, C. Bailey, W. Azelee, Modified tin(Ⅳ) oxide (M/SnO2 M=Cr, LA, Pr, Nd, Sm, Gd) catalysts for oxidation of carbon monoxide and propane, J. Catal.186 (1999) 147.
[83]P.W. Park, H.H. Kung, D.-W. Kim, M.C. Kung, Characterization of SnO2/Al2O3 lean NOx catalysts, J. Catal.184 (1999) 440.
[84]P.G. Harrison, in:P.G. Harrison (Ed.), Chemistry of Tin, Blackie, Glasgow,1989 (Chapter 12).
[85]K. Sekizawa, H. Widjaja, S. Maeda, Y. Ozawa, K. Eguchi, Low temperature oxidation of methane over Pd/SnO2 catalyst, Appl. Catal. A 200 (2000) 211.
[86]H. Widjaja, K. Sekizawa, K. Eguchi, Low-temperature oxidation of methane over Pd supported on SnO2-based oxides, Bull. Chem. Soc. Jpn.72 (1999) 313.
[87]T. Takeguchi, O. Takeoh, S. Aoyama, J. Ueda, R. Kikuchi, K. Eguchi, Strong chemical interaction between PdO and SnO2 and the influence on catalytic combustion of methane, Appl. Catal. A 252 (2003) 205.
[88]P.G. Harrison, N.C. Lloyd, W. Daniell, The nature of the chromium species formed duringthe thermal activation of chromium-promoted tin(Ⅳ) oxide catalysts:an EPR and XPS study, J. Phys. Chem. B 102 (1998) 10672.
[89]P.G. Harrison, N.C. Lloyd, W. Daniell, C. Bailey, W. Azelee, Evolution of microstructureDuringthermal activation of chromium-promoted tin(Ⅳ) oxide catalysts:an FT-IR, FT-Raman, XRD, TEM and XANES/EXAFS study, Chem. Mater.11(1999)896.
[90]P.G. Harrison, W. Azelee, A.T. Mubarak, C. Bailey, W. Daniell, N.C. Lloyd, in:N. Kruse, A. Frennet, J.-M. Bastin (Eds.), Catalysis and Automotive Pollution Control. IV, Studies in Surface Science and Catalysis, vol.116, Elsevier, Amsterdam,1988.
[91]G. Centi, F. Trifiro', Oxidation catalysts based on antimony mixed oxides with rutile-type structures, Catal. Rev.28 (1986) 165.
[92]F.J. Berry, Tin-antimony oxide catalysts, Adv. Catal.30 (1981) 97.
[93]H.J. Herniman, D.R. Pyke, R. Reid, An investigation of the relationship between the bulk and surface composition of tin and antimony mixed oxide catalysts and the oxidative dehydrogenation of 1-butene to butadiene, J. Catal.58 (1979) 68.
[94]Y.M. Cross, D.R. Pyke, An X-ray photoelectron spectroscopy study of the surface composition of tin and antimony mixed metal oxide catalysts, J. Catal.58 (1979) 61.
[95]Y. Boudeville, F. Figueras, M. Forissier, J.L. Portefaix, J.C. Vedrine, Correlations between X-ray photoelectron spectroscopy data and catalytic properties in selective oxidation on Sb-Sn-O catalysts, J. Catal.58 (1979) 52.
[96]F. Sala, F. Trifiro', Oxidation catalysts based on tin-antimony oxides, J. Catal.34 (1974)68.
[97]N.G. Valente, L.E. Cadu's, O.F. Gorriz, L.A. Arru'a, J.B. Rivarola, Synergy in Sn-Mo-O catalysts:the selective oxidation of methanol, Appl. Catal. A 153 (1997) 119.
[98]L.J. Lakshmi, E.C. Alyea, ESR, FT-Raman spectroscopic and ethanol partial oxidation studies on MoO3/SnO2 catalysts made by metal oxide vapor synthesis, Catal. Lett.59 (1999)73.
[99]M. Niwa, H. Yamada, Y. Murakami, Activity for the oxidation of methanol of a molybdena monolayer supported on tin oxide, J. Catal.134 (1992) 331.
[100]T. Ono, H. Kamisuki, H. Hisashi, H. Miyata, A comparison of oxidation activities and structures of Mo oxides highly dispersed on group IV oxide supports, J. Catal. 116(1989)303.
[101]M. Daturi, L.G. Appel, Infrared spectroscopic studies of surface properties of Mo/SnO2 catalyst, J. Catal.209 (2002) 427.
[102]M. Niwa, M. Mizutani, M. Takahashi, Y. Murakami, Mechanism of methanol oxidation over oxide catalysts containingMoO3, J. Catal.70 (1981)14.
[103]R. Skolmeistere, L. Leitis, M. Shymanska, J. Stoch, Influence of preparation conditions on activity andphysical properties of V2O5-SnO2 catalyst for oxidative destruction of residual pyridine bases, Catal. Today 17 (1993) 79.
[104]S.L.T. Andersson, S. Jaras, Activity measurements and ESCA investigations of a V2O5/SnO2 catalyst for the vapor-phase oxidation of alkylpyridines, J. Catal.64 (1980)51.
[105]S. Bordoni, F. Catellani, F. Cavani, F. Trifiro', M. Gazzano, Nature of vanadium species in SnO2-V2O5-based catalysts. Chemistry of preparation, characterization, thermal stability and reactivity in ethane oxidative dehydrogenation over V-Sn mixed oxides, J. Chem. Soc. Faraday Trans.90 (1994) 2981.
[106]P.G. Harrison, Tin(Ⅳ)oxide:surface chemistry, catalysis and gas sensing, in:P.G. Harrison (Ed.), Chemistry of Tin, Blackie, Glasgow,1989.
[107]P. Aigrain, C. Dugas, Adsorption sur les semi-conducteurs, Z. Elektrochem.56 (1952) 363.
[108]P.B. Weisz, Electronic barrier layer phenomena in chemisorption and catalysis, J. Chem.Phys.20 (1952) 1483.
[109]K. Hauffe, H.J. Engel, Zum Mechanismus der Chemisorption vom Standpunkt der Fehlordnungstheorie, Z. Elektrochem.56 (1952) 366.
[110]K. Hauffe, The application of the theory of semiconductors to problems of heterogenous catalysis, Adv. Catal.7 (1955) 213.
[111]Th. Wolkenstein, Sur les differents types de liaisons lors de L_adsorption chimique sur dessemi-conducteurs, Adv. Catal.9 (1957) 807.
[112]Th. Wolkenstein, Sur le mecanisme de 1_action catalytique des semi-conducteurs, Adv. Catal.9(1957)818.
[113]J. Haber, M. Witko, Oxidation catalysis-electronic theory revisited, J. Catal.216 (2003)416.
[114]J. E. Martin,D. Adolf,The sol-gel transition in chemical gels,Annu. Rev. Phys. Chem.42(1991)311-339
[115]郭玉忠,黄瑞安,孙加林,Sn02溶胶系水解缩合实验研究,硅酸盐学报,29(2)(2001)157-162
[116]Naichao Li, Charles R. Martin, A High Rate, High Capacity, Nanostructured Sn-based Anode Prepared Using Sol-Gel Template Synthesis, J. Electrochem. Soc.148(2)A (2001)164-170
[117]C. B. Murray, C. R. Kagan, M. G. Bawendi, Synthesis and characterization of mono-disperse nano-Crystals and close-packed nanocrystal assemblies, Annu. Rev. Mater. Sci.30(2000)545-610
[118]R.Pecora,Dynamic Light Scattering,New York, Plenum Press,1985,p7-301.
[119]郭玉忠,黄瑞安,王剑华,Sn02溶胶-凝胶转变的流变学研究,无机材料学报,16(2)(2001)249-255
[120]S.Schiller,G. Beister, M. Numann, G. Jaesch, Vacuum coating of large areas, Thin Solid Films.96(1982)199-216
[121]R. Kalbskopf, Continuous chemical vapor deposition of tin oxide, Thin Solid Films.77(1981)65-66
[122]N. Jackson, J. Ford Experience in the control and evaluation of coatings on glass containers, Thin Solid Films.77(1981)23-39
[123]M.F.Bechtold, Silicic acid from tetraethyl silicate hydrolysis polymerization and properties, J. Am. Chem Soc,90 (1968) 4590-4598
[124]Laine. R.M. Chemical processing of glasses, In:. Mackenzie. J. D, Ulrich. D. R, eds.Sol-Gel Optics, San Diego, SPIE,1990,1328:96-301
[125]E.T. A Pope., J.D Mackenzie,Role of catalysts in silica sol-gel route. J.Non-cryst. Solids,1986,87(1968)185-196
[126]P.J. Flory et al,J. Am. Chem. Soc.,73(1951):1904-1908
[127]J.E.Martin,slow aggregation of colloidal silica, Phys. Rev.,36A (7) (1987) 3415-26
[128]Ruian Huang, Yuzong Guo,Formation and characterization of tin oxide aerogel derived from sol-gel process based on Tetra(n-butoxy) tin(Ⅳ), J. noncrystalline solids,2005,351(1):23-38
[129]张济忠,分形,p 104-347,清华大学出版社,1995
[130]P. G. J. Van Dongen, M. H.Ernst,Dynamics scaling in kinetics of clustering, Phys. Rev. Lett.54(13)(1985)1396-1399
[131]J.E.Martin, J.Wilcoxon,D.Adolf, Critical Exponents for the Sol-Gel Transition, Phys. Rev..36 A[4] (1987) 1803-10
[132]M.Daoud,J.E.Martin,1989, The Fractal Approach to Heterogeneous Chemistry, ed. D.Avnir, pp.109-130, New York:Wiley.
[133]J.E.Martin,J.P.Wilcoxon,D.Schaefer,et al,Fast aggregation of colloidal silica, Phys. Rev.,41A (8) (1990) 4379-91
[134]C.J.Brinker, G.W.Sherer, J. Non-Cryst. Solids,72 (1985) 345
[135]G. Frank, E. Kauer,H. Kostlin, Transparent heat-reflecting coatings based highly doped emiconductors,Thin Solid Films.77(1981)107-117
[136]王剑华,孙加林,Sn02凝胶干燥及固化过程中的结构变化,无机材料学报,16(3)(2001)410-418.
[137]K.Seeger,半导体物理学,徐乐,钱建业译,人民教育出版社,1980,P57-102,392-498.
[138]MNagasawa, S Shionoya, Phys. Lett.,1966,22(1966)409-414.
[139]N F Mott,Rev. Mod. Phys.,40(10)(1966)677-683.
[140]N F Mott,Advan.Phys., Electrons in disordered structures,16(1967)49-144
[141]C. G. Granqvist, Radiative heating and cooling with spectrally selective surfaces, Applied Optics.20(15)(1981)2606-2615