Fundamentals of Nanomaterials(2)(纳米材料基础)
复旦大学成功制备新型二维晶体黑磷
在未来 的集成 电路里” 。
面 向未 来的 二维 黑磷 材料
黑磷 的半导体 能隙是个直接 能隙 ， 这个特性让 它的光学
年产值 总计超过 ２ ０ 亿 元 ，目前河北 占地 ５ ０亩 的基 地 已经基 和 光 电性能 同其 他材料 （ 包括硅 和硫化钼 ）相 比有 巨大 的优 本完成 ，设备正在陆续调 试中。
能吸光饱和 ，然后夜间再慢慢释放 出来，也不需要人工控制 ， 模较大的投资推进 落实速度 又 比较慢 。 还能够最低限度地消耗能量 ，使 用寿命在 ８ 年 ～ｌ ０年 。”纳 明新材料董事长张 明德介绍 ，纳 米稀 土产 品不仅更节能环保 ， 还要 比传统照 明方式更省钱 。 凭着纳米稀土 发光材料这项技术 ，纳明新材料获 评国家 高新技术企业称号 ，目前 已经拥有 ７ ８ 项 专利 ，其 中发 明专利 就达 １ ６项 。但是 ，该产品并非完美 无瑕 ，据 了解 ，其在傍 晚 和清晨 ，当天色介于亮与不 亮之间时 ，它还在 吸收光源可 能
体。与石墨烯 最大的不 同是 ，黑磷有一个 半导体 能隙。 “ 两
年 前 中 国 科 技 大 学 的 陈 仙 辉 教 授 告 诉 我 他 们 可 以 生 长 黑 磷
产业扩张遇资金瓶颈
时， 当时直觉就告 诉我 ， 这有 可能是一 个很 好的半导 体材料 ， ”
“ 去年 接 到了 １ ． ２亿 元 的订 单 ，但 是 只完 成 了 ３ ０ ０ ０万 张远波教 授说 ， “ 果然 ，现在我们把 黑磷 做成纳米厚 度的二 元。”张明德表示 ，由于资金的缺乏 ，设 备等无法 满足生产 维 晶体 后 ，发现它有 非常好的半导体 性质 ，这样就 有可能用 的现实需求 ，而市场 的需求正在呈持续增长趋势 。 根据纳 明新 材料的规划 ，其将继 续 以松 山湖作 为总部 ，
《材料科学基础》作业答案
• 3、Fick扩散第二方程的高斯解适合求解总量为M 的扩散元素沉积为一薄层扩散问题 ；Fick扩散 第二方程的误差函数解适合求解 无限长棒（扩 散偶）或半无限长棒的扩散问题。
• 4、扩散的微观机理有 空位扩散 、 间隙扩散、 位 错扩散 、 表面扩散、晶界扩散 等。
• 5、空位扩散的阻力比间隙扩散 大 ，激活能 高。
第三章 晶体结构缺陷 P116
• 一、填空题 • 1、按几何组态，晶体中的缺陷分为 点缺陷 、 线
缺陷 、面缺陷 和体缺陷。 • 2、点缺陷主要包括 空位、 间隙原子、置换原子 ；
线缺陷有 位错 ；面缺陷包括 晶界、相界、表面 等。 • 3、描述位错性质及特征的是 柏氏矢量b 。 • 4、位错的类型有 刃位错 、 螺位错 和 混合位 错。
• 11、MgO晶体具有 NaCl型结构，其对称型是
3L4 4L36L29PC ，晶族是 高级晶族 ，晶系是 立 方晶系 ，晶体的键型是 离子键 。
• 12、硅酸盐晶体结构中的基本结构单元是 硅 氧四面体[SiO4]。
• 13、几种硅酸盐晶体的络阴离子分别为[Si2O7]6-、 [Si2O6]4-、[Si4O10]4-、[AlSi3O8]1-，它们的晶体 结构类型分别为 组群状 ， 链状 ， 层状 ，和 架状 。
• MgO的分子量为（24.305 +15.999 ）40.30， •阿佛加得罗常数是6.0238×1023， •每个MgO 分子的质量A为： 40.30/(6.0238×1023)。
MgO结构：z=4 • MgO的密度ρ
Z M a /3 N A 4 4 (0 0 ..3 4 0 2 4 /( 6 .1 0 0 2 7 )1 3 0 2 3 ) 3 .5 1 (g /c m 3 )
无机非金属材料工程专业英语 第2章
Fundamentals of Materials Science and Engineering
LearningObjectives
After careful study of this chapter you should be able to do the following: 1. Name the two atomic models cited, and note the differences between them. 2. Describe the important quantum-mechanical principle （量子 理论）that relates to electron energies. 3. (a) Schematically plot attractive, repulsive, and net energies versus interatomic separation for two atoms or ions. (b) Note on this plot the equilibrium separation and the bonding energy. 4. (a) Briefly describe ionic, covalent, metallic, hydrogen, and van der Waals bonds. (b) Note what materials exhibit each of these bonding types.
Fundamentals of Materials Science and Engineering
Chapter 2 Atomic Structure and Interatomic Bonding
Covalent Bond(SiO2 B2O3)
Nanomaterials 纳米材料
Nanomaterials 纳米材料Scanning Tunneling Microscope (STM) 扫描隧道电子显微镜Zero (one, two, three)-dimension 零、一、二、三维Size Effect - Kubo theory 尺寸效应—久保理论(1) Quantum size effect 量子尺寸效应(2) Small size effect 小尺寸效应Surface effect 表面效应 Dielectric confinement effect 介电限域效应Coulomb blockade and Quantum tunneling effect 库伦阻塞与量子隧穿效应Primary particles （一次粒子） Secondary particles（二次粒子）Precipitation（沉淀） Agglomeration （团聚体）Scanning electron microscope (SEM) （扫描电镜）Transmission electron microscope (TEM) （透射电镜）High-resolution transmission electron microscope (HRTEM) （高分辨透射电镜）Clusters 团簇 Nanoparticle 纳米颗粒 Supersaturated Vapor 过饱和蒸气Heterogeneous nucleation 异相成核 Homogeneous nucleation 均相成核Magic Numbers 幻数Mechanical Attrition/ Mechanical Alloying (MA) 机械研磨/机械合金化High-energy Ball Milling 高能球磨Contamination 污染物Comminution 粉碎Intermetallic 金属间化合物Oxide-dispersion strengthened superalloys 氧化物弥散增强超合金Nanocomposites 纳米复合材料Dislocation 位错sol-gel溶胶-凝alkoxide solution 醇盐溶液colloidal sols 胶体溶胶microporous monoliths 多孔块体材料anisotropic / isotropic shrinkage各向异性/各向同性收缩polymer pyrolysis聚合物高温分解hydrolysis 水解A green body生坯Pressureless sintering 无压烧结Inhomogeneous sintering 不均一烧结 Densification 致密度Porosity 多孔性 Pressure Assisted Sintering 压力辅助烧结Sinter-forging 烧结锻压Electronic effects 电子效应 Support effects 载体效应Shape effects 形状效应 Zeolite ( Molecular sieve) 沸石(分子筛) Catalyst 催化剂 Adsorbent 吸附剂 Isomerization 异构化Yield Strength 屈服强度 Hall-Petch equationHP-霍尔佩奇方程Diffusion creep rate 扩散蠕变速率Coble creep 扩散蠕变Triple junctions 三叉晶界Superplasticity 超塑性Softening mechanism 软化机制Mass spectra 质谱 Fullerene 富勒烯 Bucky ball 巴基球Electric arc 电弧High-performance liquid chromatography 高效液相色谱法Nuclear magnetic resonance 核磁共振 Allotrope 同素异形体 Pentagon五边形Hexagon 六边形 Icosahedron 二十面体。
北航在规则形貌非晶纳米材料制备方面获突破
组与国家纳米科学 中心蒋兴宇研究员课题组合作 ．
发现 了一 种便捷 且 廉价 的合 成荧 光碳 纳米 颗粒 的新 方 法 ，研 究 了 基 于 该 碳 纳 米 颗 粒 的 高 选 择 性 的
成 。所制备的分散性铜纳米颗粒稳定性好 ，放置 ６
个 月也 无沉 积迹 象发 生 。 来源 ： 《 中 国科 学报 》
温度低和原料可再生等优点 。同时对其性质的研究
结果显示 ，由该方法合成得到的荧光碳纳米颗粒具
胜教授团队通过设计一种新 的旋转平移制备法 ，首 次成功制备出可拉伸的线状超级 电容器 ，从而有效
结合 了高分子材料 的弹性及碳纳米管的优异 电学和
有如下特点 ：１ ． 很高的荧光 量子产率 ；２ ． 很好 的
中科院宁波材料所研究人员采用生物分子辅助 合成技术制备 了具有高稳定分散 的水溶性纳米铜颗 粒 ，从而为合成在生物技术领域有潜在应用的多种
纳 米 颗 粒 提 供 了一 种 有 效 方 法 。相 关 成 果 发 表 于
《 胶体与界面科学杂志》 。该制备过程 中不添加任何
其 他 的介 质 稳 定 剂 ．有 效 避 免 了 有 机 残 留物 的生
化 学 杂志 Ａ 》 。 核泄漏 造 成 的核 辐 射污染 是 目前 已知 核 能应 用
制备出可拉伸的线状超级电容器 。这种电容器可弯 曲 、折叠 和 拉伸 ．且在 拉 伸 ７ ５ ％的情 况下 仍 能 １ ０ ０ ％保持 电容器 的各项性能 。这种线状 电容器可 进一步编织成各种形状 的织物 ，并可集成于各种微 型 电子器件上 ．从而满 足未来对 于微型能源 的需
法 。该成 果最 近发表 在 《 美 国化 学会 志》上 （ Ｊ ．
Ａ ｍ． Ｃ ｈ ｅ ｍ． Ｓ ｏ ｃ ． ，２ ０ １ ３ ，１ ３ ５ ，１ ６ ０ ８ ２ ） 。
二维纳米材料范文
二维纳米材料范文二维纳米材料（two-dimensional nanomaterials）是一类具有二维特性的纳米材料，具有出色的性能和广泛的应用潜力。
它们由只有几十个原子乃至一个原子厚的单层材料组成，具有高度可调控性和可扩展性。
这一类材料在材料科学、纳米技术和电子器件等领域受到了广泛的关注。
二维纳米材料的最典型代表是石墨烯（graphene），它是由碳原子构成的单层二维结构，具有出色的导电性和机械性能。
石墨烯不仅具有高电导率，还具有优异的热导率、机械强度和柔韧性。
因此，它在电子器件、能源储存、传感器、透明导电薄膜等领域有着广泛的应用。
此外，二维纳米材料还包括二硫化钼（molybdenum disulfide）、二硫化钨（tungsten disulfide）等过渡金属二硫化物材料。
这些材料具有优异的光学和电子特性，可用于光电器件、催化剂、传感器等领域。
二维纳米材料的制备方法主要有机械剥离、化学气相沉积、溶液法、热剥离等。
其中，机械剥离是最早的制备方法，通过用胶带对固体材料进行多次剥离得到单层材料。
化学气相沉积则是通过在高温下，以特定化合物为前驱体，在衬底上进行化学反应制备出二维纳米材料。
溶液法则通过将材料分散到溶液中，然后在衬底上进行沉积和转移得到二维纳米材料。
然而，二维纳米材料也面临一些挑战。
首先，二维纳米材料的制备需要高度精确的控制条件，如温度、压力和浓度等。
其次，由于材料的表面积大幅缩小，其稳定性和可靠性仍然是一个挑战。
此外，二维纳米材料的大规模制备和集成技术也需要进一步研究和发展。
综上所述，二维纳米材料作为一类新兴的纳米材料，具有出色的性能和广泛的应用潜力。
通过研究和开发这些材料，将有助于开拓新的领域和应用，推动纳米技术的进一步发展。
纳米材料与纳米团簇
1990年美国国际商业机 器公司（IBM）的艾格 勒在镍金属（110）表面 用35个氙原子排出 “IBM”字样。
1993年中国科学院北京 真空物理实验室操纵原 子写出“中国”二字。
1991年，日本科学家饭 岛澄男发现碳纳米管， 它的质量只有同体积钢 的1／6，强度却是钢的 100倍。用碳纳米管做 绳索，是唯一可以从月 球上挂到地球表面，而 不被自身重量所拉断的 绳索 。
界面效应
纳米材料具有非常大的界面。界面的原子 排列是相当混乱的，原子在外力变形的条 件下很容易迁移，因此表现出很好的韧性 与一定的延展性，使材料具有新奇的界面 效应。
界面效应
纳米铁材料，可以制成高强度、高韧性的 特殊钢材，强度提高12倍，硬度提高2～3 个数量级。屈服强度和抗拉强度分别超过 1200 MPa和1400 MPa。
5、 用于制造微型武器。利用纳米技术可以
把传感器、电动机和数字智能装备集中在一 块芯片上，制造出几厘米甚至更小的微型装 置。在未来战场上，将出现能像士兵那样执 行军事任务的超微型智能武器装备。据报道， 美国研制的小型智能机器人，大的像鞋盒子 那么大，小的如硬币，它们会爬行、跳跃甚 至可飞过雷区、穿过沙漠或海滩，为部队或 数千公里外的总部收集信息。微型机电武器 还可用于敌我识别、探测核污染和化学毒剂、 无人侦察机等。
5、纳米技术如果应用在陶瓷上，可使陶瓷具有超 塑性，大大增强了陶瓷的韧性，不怕摔，不怕碎， 陶瓷坚固无比。另外，还能用纳米技术识别化学和 生物传感器材料。令科学家高兴的是，纳米钛与树 脂化合后生成的多种全新涂料，具有多种同类产品 无法相比的优越性，在海水中浸泡10年不损，并 具有神奇的自我修复能力和自洁性，纳米钛还作为 唯一对人植物神经、味觉没有任何影响的金属，其 用途广泛。
纳米材料基础(英文ppt)
ClassificationClassification is based on the number of dimensions, which are not confined to the nanoscale range (<100 nm).(1) zero-dimensional (0-D),(2) one-dimensional(1-D),(3) two-dimensional (2-D), and(4) three-dimensional (3-D).2One-dimensional nanomaterialsOne dimension that is outside the nanoscale.This leads to needle like-shaped nanomaterials.1-D materials include nanotubes, nanorods, andnanowires.1-D nanomaterials can beAmorphous or crystallineSingle crystalline or polycrystallineChemically pure or impureStandalone materials or embedded in within another medium Metallic, ceramic, or polymeric4Two-dimensional nanomaterials Two of the dimensions are not confined to the nanoscale.2-D nanomaterials exhibit plate-like shapes.Two-dimensional nanomaterials include nanofilms,nanolayers, and nanocoatings.2-D nanomaterials can be:Amorphous or crystallineMade up of various chemical compositionsUsed as a single layer or as multilayer structuresDeposited on a substrateIntegrated in a surrounding matrix materialMetallic, ceramic, or polymeric5Three Three--dimensional space showing the relationships among 0among 0--D, 1D, 1--D, 2D, 2--D, and D, and 33-D D nanomaterials nanomaterials nanomaterials..7Summaryof 2-D and3-Dcrystallinestructures 8Matrix-reinforced and layerednanocompositesThese materials are formed of two or more materials with very distinctive properties that act synergistically to create properties that cannot be achieved by each single material alone. The matrix of the nanocomposite, which can be polymeric, metallic, or ceramic, has dimensions larger than the nanoscale, whereas the reinforcing phase is 9commonly at the nanoscale.Carbon materials2s and 2p electrons available for bondingDiamond and graphite are twoallotropes of carbon:pure forms of the same element that differ in structure.11DIAMOND- chemical bonding is purely covalent - highly symmetrical unit cell - extremely hard - low electrical conductivity - high thermal conductivity (superior) - optically transparent - used as gemstones and industrial grinding, machining and cutting12GRAPHITE• Layered structure with strong bonding within the planar layers and weak, van der Waals bonding between layers • Easy interplanar cleavage, applications as a lubricant and for writing (pencils) • Good electrical conductor • Chemically stable even at high temperatures • excellent thermal shock resistanceApplications:Commonly used as heating elements (in non- oxidizing atmospheres), metallurgical crucibles, casting molds, electrical contacts, brushes and resisto1r3s, high temperature refractories, welding electrodes, air purification systems, etc.GraphiteGraphite is a layered compound. In each layer, the carbon atoms are arranged in a hexagonal lattice with separation of 0.142 nm, and thedistance between planes is 0.335 nmThe acoustic and thermal properties of graphite are highly anisotropic, since phonons propagate very quickly along the tightly-bound planes, but are slower to travel from one plane to another.14/wiki/GraphiteGrapheneGraphene is an one-atom-thick planar sheet of sp2-bonded carbon atoms that are densely packed in a honeycomb crystal lattice. It can be viewed as an atomic-scale chicken wire made of carbon atoms and their bondsThe carbon-carbon bondlength in graphene is about0.142 nm. Graphene is thebasic structural element ofsome carbon allotropesincluding graphite, carbon15nanotubes and fullerenes.Allotropes of carbon3D 0D1D16a) diamond b) graphite c) lonsdaleite(hexagonal diamond) d) - f) fullerenes (C60, C540, C70); g) amorphous carbon h) carbon nanotube2D - ???Wikipedia17SCIENCE, June 2010If there's a rock star in the world of materials, it's graphene: single-atom–thick sheets of carbon prized forits off-the-charts ability to conduct electrons and for being all but transparent.Those qualities make graphene a tantalizing alternative for use as a transparent conductor, the sort now found in everything from computer displays and flat panel TVs to ATM touch screens and solar cells. But the material has been tough to manufacture in anything larger than flakes a few centimeters across. Now researchers have managed to create rectangular sheets of graphene 76 centimeters in the diagonal direction and even use them to create a working touchscreen display18Quantum effectsThe overall behavior of bulk crystalline materials changes when the dimensions are reduced to the nanoscale. For 0-D nanomaterials, where all the dimensions are at the nanoscale, an electron is confined in 3-D space. No electron delocalization (freedom to move) occurs. For 1-D nanomaterials, electron confinement occurs in 2-D, whereas delocalization takes place along the long axis of the nanowire/rod/tube. In the case of 2-D nanomaterials, the conduction electrons will be confined across the thickness but delocalized in the plane of the sheet.19Electrons confinementFor 0-D nanomaterials the electrons are fully confined. For 3-D nanomaterials the electrons are fully delocalized. In 1-D and 2-D nanomaterials, electron confinement and delocalization coexist. The effect of confinement on the resulting energy states can be calculated by quantum mechanics, as the “particle in the box” problem. An electron is considered to exist inside of an infinitely deep potential well (region of negative energies), from which it cannot escape and is confined by the dimensions of the nanostructure.20Energieswhere h¯ ≡ h/2π, h is Planck’s constant, m is the mass of the electron, L is the width (confinement) of the infinitely deep potential well, and nx, ny, and nz are the principal quantum numbers in the three dimensions x, y, and z.The smaller the dimensions of the nanostructure(smaller L), the wider is the separation between theenergy levels, leading to a spectrum of21discreet energies.What’s different at the nanoscale?Each of the different sized arrangement of gold atoms absorbs and reflects light differently based on its energylevels, which are determined by size and bonding arrangement. This is true for many materials when the particles have a size that is less than 100 nanometers in atleast one dimension.22Energy levels in infinite quantum well23The finite potential wellFor the finite potential well, the solution to the Schrodinger equation gives a wavefunction with an exponentially decaying penetration into the classically forbidden region.Confining a particle to a smaller space requires a larger confinement energy. Since the wavefunction penetration effectively "enlarges the box", the finite well energy levels are lower than thosefor the infinite well.The solution for -L/2 < x < L/2 and elsewhere must satisfy the equationWith the substitution24The finite potential well25Comparison of Infinite and Finite Potential WellsEigenstates with E < V0 are bound or localized.26Eigenstates with E > V0 are unbound or delocalizedElectron energy densityThe behavior of electrons in solids depends upon the distribution of energy among the electrons:This distribution determines the probability that a given energy state will be occupied, but must be multiplied by the density of states function to weight the probability by the number of states available at a given energy.Density of states in (a) metal, (b) semimetal (e.g.graphite).27。
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Slowest step dominates
- reaction-rate limited process
- mass-transport limited process
• Reactant species must be absorbed on substrate for deposition to take place. After absorption, the reactive species can remain fixed at the surface site or migrate along the surface. This is temperature dependent.
Co-precipitation method
This method can make the cations to be mixed in the atomic level in solution. pH value is an important parameter.
• 4.5.4 Sol-gel method
– 4.5.1 Precipitation method
precipitator Raw materials (solution) Precursor precipitate Filter, gather
Dry, calcination
Nanoparticles
Precipitate
The size of the nanoparticle depends on the solubility.
Nucleation and growth • Initial formation of cluster (nuclei) • Clusters impinge and grow together to form continuous film (coalescence)
• 4.5 Liquid phase synthesis method
Cascade process of ionization. Electrons are „e−‟, neutral atoms „o‟, and cations „+‟ Artificial plasma produced in air by a Jacob's Ladder
– 4.3.2 E-beam evaporation
• 4.2 Solid phase method
– 4.2.1 Mechanically milling (Size reduction process)
• Two processes: Crush and Milling
Ball milling
Low velocity
Suitable velocity
E-beam is guided by magnetic field and can be scanned across the metal, can be accelerated to any desired level.
- 4.3.3 Sputtering
Sputtering deposition
Magnetron sputtering
Sputtering sources are usually magnetrons that utilize strong electric and magnetic fields to trap electrons close to the surface of the magnetron, which is known as the target. The electrons follow helical paths around the magnetic field lines undergoing more ionizing collisions with gaseous neutrals near the target surface than would
Such bottom-up approaches should, broadly speaking, be able to produce devices in parallel and much cheaper than top-down methods, but could potentially be overwhelmed as the size and complexity of the desired assembly increases.
– Bottom-up
• Bottom-up approaches, in contrast, use the chemical properties of single molecules to cause single-molecule components to (a) self-organize or self-assemble into some useful conformation, or (b) rely on positional assembly. These approaches utilize the concepts of molecular self-assembly and/or molecular recognition
• 4.4 Chemical vapor deposition (CVD) method
Chemical vapor deposition (CVD) is a chemical process used to produce highpurity, high-performance solid materials.
– 4.3.1 Thermal evaporation PVD method
– 4.3.2 Plasma-assisted PVD method
Plasma is loosely described as an electrically neutral medium of positive and negative particles (i.e. the overall charge of a plasma is roughly zero). It is important to note that although they are unbound, these particles are not „free‟. When the charges move they generate electrical currents with magnetic fields, and as a result, they are affected by each other‟s fields. This governs their collective behavior with many degrees of freedom.
• 4.3 Physical vapor deposition (PVD) method
PVD method involves the conversion of solid material into a gaseous phase by physical processes, and then the material is cooled and redeposited on a substrate.
Sputtering is expensive and can lead surface damage with certain degree.
DC sputtering
The simplest sputtering approach: in a vacuum chamber target material (cathode = neg. potential) is eroded and deposits on the substrate (anode = ground or pos.potential)
Critical velocity
Colloid mill
A: hollow rotation axis
B & C: Rotation plate
Planetary mill
Jet mill with nanoairflow (high energy)
A) Ball milling
B) Jet mill
Surface reaction rate increases with increasing temperature at very high temperature Reaction rate > reactant arrival rate Mass- transport limited At low temperatures Reaction rate < reactant arrival rate Reaction rate limited
otherwise occur.
RF Sputtering (radio frequency)
For DC sputtering, target electrode is conducting, to sputter dielectric materials, RF power discharge to avoid the accumulation of electric load. Typically 13.56 MHz.
Matters need attention:
1. Safety during the mechanical milling; 2. The limit of the milling.
Milling Agglomeration
– 4.2.2 Solid-state reaction
• Solid-state reactions offer the possibility of generating nanoparticles by controlled phase transformations or reactions of solid materials.