温度对云母/水界面纳米气泡形成影响的研究

最近固液界面存在纳米气泡已经引起人们越来越多的关注。虽然经典热力学理论认为室温下水中纳米气泡不能稳定存在 ,但近几年越来越多的研究结果却表明固液界面存在纳米气泡 ,并引起疏水长程作用力。目前直接探测固液界面纳米气泡的最有力手段是原子力显微镜 (AFM)技术 ,尤其是AFM的轻敲模式非常适合于柔软样品的研究 ,因此是目前探测固液界面纳米气泡的最有力手段。本文利用轻敲模式对醇水替换方式产生的纳米气泡进行成像 ,籍以研究液体温度对纳米气泡形成的影响。在研究中发现 ,液体的温度对纳米气泡的形成有显著的影响。当液体温度升高…     

固液界面纳米气泡的研究

在经典热力学理论中，室温下水中纳米气泡被认为是不能稳定存在的。近年来随着对疏水表面研究的深入，越来越多的现象暗示固液界面存在纳米气泡，并引起疏水长程作用力。目前直接探测固液界面纳米气泡的最有力手段是AFM，但它只能观察纳米气泡的形貌，无法对其进行直接定性，很有必要提供纳米气泡存在和来源的更直接证据。在云母表面进行乙醇和水替换形成纳米气泡，从成像条件和脱气对纳米气泡的影响两方面进行系统研究。不同成像模式和成像条件下AFM观察到的差异在一定程度上证明了观察到的就是纳米气泡。脱气实验结果表明，经脱气后乙醇和水形成纳米气泡的数量和概率明显降低，表明乙醇和水中溶解的气体是纳米气泡的来源，并为固液界面存在纳米气泡提供了更直接的证据。     

云母表面改性的AFM研究

采用原子力显微镜(AFM)对γ-甲基丙烯酰氧丙基三甲氧基硅烷(KH-570)改性后的云母表面形貌进行观测,并综合表面粗糙度Rq、粒子高度D及Z方向最高高度等参数考察了清洗方式、偶联剂浓度以及清洗和烘干顺序对改性后云母表面形貌的影响.实验结果显示:改性后云母表面粗糙度受云母表面的点缺陷、清洗方式及处理顺序等因素影响,而偶联剂分子在云母表面的存在形态受改性溶液中偶联剂浓度的影响.随着偶联剂浓度的减小,改性后云母表面上偶联剂由网状变为分散点状.     

铝硅合金表面纳米颗粒的原子力显微镜观察

利用原子力显微镜首次观察到２００℃磁控溅射铝硅合金表面存在纳米颗粒，经测量，此纳米颗粒直径约２０ｎｍ、高１ｎｍ。根据此纳米颗粒的分布，讨论了磁控溅射薄的生长机理，同时，还讨论了此纳米颗粒对半导体工艺的影响。     

微加工硅表面基于AFM的纳米压痕测量与分析

原子力显微镜 (AFM )在完成对单晶硅的微加工后 ,其金刚石针尖被用做一个纳米压痕头以实现微加工区域内外机械性质的测量与分析。结果表明 ,以安装有金刚石针尖的AFM在经过化学机械抛光的硅基片上所进行的微加工 ,即使使用极小的切削力也会在加工表面形成变质层 ,但是其厚度值要小于化学机械抛光的硅表面变质层。由AFM测量的纳米级硬度值要大于由传统的Vickers和Hysitron硬度测试仪所测量的值。另外 ,随着AFM压入载荷的减小 ,纳米级硬度值呈现出增加的趋势 ,这是由于在很小的压入载荷下所呈现出的压痕尺寸效应所导致     

微加工硅表面基于AFM的纳米压痕测量与分析

原子力显微镜(AFM)在完成对单晶硅的微加工后,其金刚石针尖被用做一个纳米压痕头以实现微加工区域内外机械性质的测量与分析.结果表明,以安装有金刚石针尖的AFM在经过化学机械抛光的硅基片上所进行的微加工,即使使用极小的切削力也会在加工表面形成变质层,但是其厚度值要小于化学机械抛光的硅表面变质层.由AFM测量的纳米级硬度值要大于由传统的Vickers和Hysitron 硬度测试仪所测量的值.另外,随着AFM压入载荷的减小,纳米级硬度值呈现出增加的趋势,这是由于在很小的压入载荷下所呈现出的压痕尺寸效应所导致.     

基于"纳米蘸笔技术"的单个纳米颗粒在不同基底表面的转移

本文介绍了一种可定位拾取并重新放置单个纳米颗粒的方法.这种技术被命名为"单颗粒纳米蘸笔技术".它采用原子力显微镜针尖作"笔",俘获基底表面的单个纳米金颗粒,并将之精确定位地转移到其它基底表面.     

氧化镁纳米薄膜的制备与AFM研究

以Mg(NO3)2为反应前驱物，采用溶胶一凝胶浸渍提拉法对氧化镁纳米粒子薄膜的制备工艺进行了详细研究，利用AFM研究了制备过程中不同条件对纳米薄膜形成的影响，寻求到较佳的制膜工艺条件。XRD结果表明，薄膜中氧化镁粒子只存在(200)和(220)晶面取向的衍射峰。     

微加工硅表面基于AFM的纳米压痕测量与分析

原子力显微镜(AFM)在完成对单晶硅的微加工后，其金刚石针尖被用做一个纳米压痕头以实现微加工区域内外机械性质的测量与分析。结果表明，以安装有金刚石针尖的AFM在经过化学机械抛光的硅基片上所进行的微加工，即使使用极小的切削力也会在加工表面形成变质层，但是其厚度值要小于化学机械抛光的硅表面变质层。由AFM测量的纳米级硬度值要大于由传统的Vickers和Hysitron硬度测试仪所测量的值。另外，随着AFM压入载荷的减小，纳米级硬度值呈现出增加的趋势，这是由于在很小的压入载荷下所呈现出的压痕尺寸效应所导致。     

AFM的DNA样品制备技术研究

AFM应用中最为关键的一步无疑是样品的制备。本文介绍DNA样品制备的几种主要方法,通过实验发展了两种适合对DNA及其碎片进行长度测量和做统计分析的制样方法,它们分别采用APS-云母和纯云母为衬底。这两种方法不仅丰富了DNA样品制备方法,对推广AFM在生物研究中的应用也具有重要意义。     

Al／C的界面观察

Al-Ti-C中间合金是铝合金的一种重要的晶粒细化剂，但由于Al液对C的润湿性很差，且C在Al中的溶解度极低，故Al和C很难直接结合，这就成为制备Al-Ti-C中间合金的一个难点。由此人们想到先将Al和C复合，熔炼时将其作为中间合金加入铝液中。目前制备Al-C复合材料的大多数方法都是在较高温度下进行，Al和C在界面处发生反应，生成了脆且不稳定的Al4C3相，而不是Al/C界面，对Al/C结合界面的报道很少。     

Observation of high interface state densities at the silicon/oxide interface for low doped polysilicon/oxide/silicon capacitor structures

In this work, we present new observations noted in the capacitance–voltage behaviour of polysilicon/oxide/silicon capacitor structures. As the active doping concentration reduces in the polysilicon layer, an anomalous capacitance–voltage behaviour is measured which is not related directly to depletion into the polysilicon gate. From examination of the frequency dependence of the capacitance–voltage characteristic, in conjunction with analysis and simulation, the anomalous capacitance–voltage behaviour is explained by the presence of a high density of near-monoenergetic interface states located at the silicon/oxide surface. The density and energy level of the interface states are determined. Furthermore, the work presents a mechanism by which the polysilicon doping level can impact on the properties of the silicon/oxide interface.     

Effect of process variations and ambient temperature on electron mobility at the SiO/sub 2//4H-SiC interface

We report the effect of processing variables on the inversion layer electron mobility of (0001)-oriented 4H-SiC n-channel MOSFETs. The process variables investigated include: i) implant anneal temperature and ambient; ii) oxidation procedure; iii) postoxidation annealing in nitric oxide (NO); iv) type of gate material, and v) high-temperature ohmic contact anneal. Electron mobility is significantly increased by a postoxidation anneal in NO, but other process variations investigated have only minor effects on the channel mobility. We also report the temperature dependence of electron mobility for NO and non-NO annealed n-channel MOSFETs.     

Intermetallic compounds formed at the interface between liquid indium and copper substrates

The interfacial reactions between liquid In and Cu substrates at temperatures ranging from 175°C to 400°C are investigated for the applications in bonding recycled sputtering targets to their backing plates. Experimental results show that a scallop-shaped Cu₁₆In₉ intermetallic compound is found at the Cu/In interface after solder reactions at temperatures above 300°C. A double-layer structure of intermetallic compounds containing scallop-shaped Cu₁₁In₉ and continuous CuIn is observed after the Cu/In interfacial reaction at temperatures below 300°C. The growth of all these intermetallic compounds follows the parabolic law, which implies that the growth is diffusion-controlled. The activation energies for the growth of Cu₁₆In₉, Cu₁₁In₉, and CuIn intermetallic compounds calculated from the Arrhenius plot of growth reaction constants are 59.5, 16.9, and 23.5 kJ/mole, respectively.     

Morphology and structure of various phases at the bonding interface of Al/steel formed by explosive welding

The bonding interface of explosively-welded aluminium and steel in three explosive conditions have been investigated by using scanning electron microscopy, transmission electron microscopy, electron diffraction and electron probe microanalysis methods. The results show that all the interfaces have the shape of waves with curled front formed by process of superplasticity and some discontinuous reacted zones. They consist of amorphous and nano sized crystals and quasi-crystals as well as the compounds such as AlFe, Al2Fe, Al3Fe and Al6Fe with various shapes. The basal steel crystal near the interface has structure of martensite and perlite crystals which are deformed by the process of superplasticity. The size of reacted zone becomes large with increasing amount of explosive charge powder and separation of the driver Al plate from the basal steel plate.     

Performance of sputtered SiO2 film as acoustic antireflection coating at sapphire/water interface

The effect of sputtered SiO2 films as an acoustic antireflection coating for matching the large acoustic discontinuity at the sapphire/water interface is experimentally and theoretically investigated in a frequency range of 200 to 1100 MHz. By the introduction of SiO2 films, the transmission loss of more than 9 dB at the interface is reduced to less than 1 dB at a quarter-wavelength frequency of SiO2 film with high reproducibility.     

Charges at a laser-recrystallized-polycrystalline-silicon/insulator interface

Capacitance-voltage characteristics have been measured to determine the interface properties at the back surface of a layer of laser-recrystallized polycrystalline silicon. The interface between the recrystallized poly-silicon and an underlying oxide layer can be characterized by an effective fixed-charge density and a fast-state density, both in the low-to-middle-10¹¹cm^-2range. Charge trapping at a polysilicon/silicon-nitride interface precludes the determination of a meaningful value of interface charge.     

Observation of nitrogen-enhanced doping deactivation at the polysilicon-oxynitride interface of pMOSFETs with 12-/spl Aring/ gate dielectrics

This letter reports the observation of a process integration issue that arises when large doses of nitrogen (>1/spl times/10/sup 15/ cm/sup -2/) are incorporated in oxynitride gate dielectric films targeting equivalent oxide thickness of 11-13 /spl Aring/. It is shown that capacitance-extracted active doping density at the polysilicon/oxynitride (poly/SiON) interface of boron-doped p/sup +/-polysilicon gated pMOSFETs decreases with increasing nitrogen dose of the oxynitride film as measured by X-ray photoelectron spectroscopy. A physical mechanism is proposed to explain experimental observations.