原子力显微镜在高分子物理实验教学中的应用

原子力显微镜主要用来表征样品的表面结构与形貌,操作容易、简便,分辨能力可达到纳米级别,是目前对材料分析与纳米科技研究的重要工具之一.以聚合物的支化结构、聚氨酯的微相分离结构、聚合物的结晶熔融行为和流延法单向拉伸制备高密度聚乙烯微孔膜4个实验为例,将原子力显微镜运用于高分子物理实验教学中,以更好地阐明聚合物结构与性能之间的关系,使学生可以更好地理解相关高分子物理的基本概念和理论,同时使他们分析和解决问题的能力得到提升.     

Al/SiO_2/Si表面Al_2O_3纳米图形的AFM阳极氧化制备方法

采用AFM阳极氧化方法,在控制AFM探针尖端电压和扫描方式的条件下,在Al/SiO2/Si表面制备了Al2O3纳米图形,图形最小尺寸为70nm.研究了表面吸附水层存在下AFM阳极氧化机理.实验结果表明AFM阳极氧化是制备金属氧化物半导体纳米器件的较好方法     

VHF-PFLWD法制备μc-SiGe薄膜的研究

分别以Si2 H6和GeH4及SiH4和GeH4两种组合气体为源气体,用甚高频等离子增强化学气相沉积(VHF-PECVD)制备μc-SiGe薄膜.用Raman散射光谱和原子力显微镜(AFM)对薄膜的结构进行研究.结果表明:与SiH4和GeH4制备的薄膜系列相比,Si2H6和GeH4制备的薄膜中Ge的融入速率相对较慢;用...     

退火工艺对钛酸锶钡薄膜结构的影响

采用射频磁控溅射在Pt/Ti/SiO2/Si(100)衬底上制备Ba0.6Sr0.4TiO3(BST)铁电薄膜,在500~750℃之间对薄膜快速退火。XRD分析表明:500℃时BST薄膜开始晶化为ABO3型钙钛矿结构,温度越高结晶越完整,晶粒越大。理论计算表明,薄膜在低温退火后无择优取向,高温退火后在(111)、(210)晶面有择优取向。退火气氛、保温时间、循环次数等因素对薄膜晶粒大小无明显影响,但对表面粗糙度和结晶程度影响较大。     

用AFM导电探针在n-Si(111)表面进行纳米加工的机理研究

本文介绍了在AFM针尖与氢钝化硅表面之间施加电场作用对硅表面进行修饰的纳米加工方法，重点讨论了加工机理。实验考虑了样品的表面状态，周围大气状况，所加电压的极性、大小和加压方式等影响纳米加工的因素。对机理的研究表明，针尖和样品之间发生的是场致电子发射而非热电子发射，电流热效应增强粒子的扩散能力，提高了电化学反应速度。最后给出了电场诱导阳极氧化扩散增强的加工机理。     

Morphology of Inductively Coupled Plasma Processed HgCdTe Surfaces

Inductively coupled plasma (ICP) processing has become the industrial processing standard for HgCdTe and its related II–VI compounds. In this study ICP processes were developed that allow several microns of HgCdTe to be plasma etched while maintaining a low root-mean-square (RMS) roughness, and even improving the surface roughness in the case of HgCdTe-on-Si. These ICP processes are superior to older electron cyclotron resonance (ECR) plasma etches. The resulting ICP plasma processed surfaces are oxygen and carbon free, have a good reflection high-energy electron diffraction (RHEED) pattern, and have only a small amount of mercury depletion, x = 0.22 to 0.47 (where x is the ratio of Cd to␣Hg), in the first 25 ? to 30 ? of the HgCdTe. Nanofeatures of the as-grown HgCdTe are retained during the process and are believed to be indicative of the fundamental defect mechanisms in the different HgCdTe etched surfaces. Results from these experiments strongly suggest that ICP plasma processes can be used to delineate pixels, etch vias, clean surfaces, and even produce epi-ready surfaces that would allow HgCdTe to become much more manufacturable, and perhaps allow the replacement of wet processing in HgCdTe.     

牛血清蛋白在亲水硅片表面吸附的原子力显微成像

本文用原子力显微术（AFM）研究了牛血清白蛋白（BSA）在亲水硅片表面的吸附，硅片表面经亲水处理后，将牛血清蛋白（BSA）吸附在表面，采用轻敲模式，可获得清晰的AFM图像，牛血清蛋白（BSA）的AFM图像表明：BSA在亲水硅片表面是单分子，水平吸附在硅片表面，且吸颗粒状；1mg/ml的BSA在吸附30min后为饱和吸附。BSA到达硅表面后，蛋白中可移动的带正电荷的基团可以趋向亲水表面，使BSA与硅表面的静电相互作用由斥力变为吸引力，BSA可以稳定地吸附在亲水硅片表面。     

Efficacy of low concentration neutralised electrolysed water and ultrasound combination for inactivating Escherichia coli ATCC 25922, Pichia pastoris GS115 and Aureobasidium pullulans 2012 on stainless steel coupons

The sanitising effect of low concentration neutralised electrolysed water (LCNEW, pH: 7.0, free available chlorine (FAC): 4 mg/L) combined with ultrasound (37 kHz, 80 W) on food contact surface was evaluated. Stainless steel coupon was chosen as attachment surface for Escherichia coli ATCC 25922, Pichia pastoris GS115 and Aureobasidium pullulans 2012, representing bacteria, yeast and mold, respectively. The results showed that although LCNEW itself could effectively reduce survival population of E. coli ATCC 25922, P. pastoris GS115 and low concentration A. pullulans 2012 in planktonic status, LCNEW combined with ultrasound showed more sanitising efficacy for air-dried cells on coupons, with swift drops: 2.2 and 3.1 log CFU/coupon reductions within 0.2 min for E. coli ATCC 25922 and P. pastoris GS115, respectively and 1.0 log CFU/coupon reductions within 0.1 min for A. pullulans 2012. Air-dried cells after treatment were studied by atomic force microscopy (AFM)/optical microscopy (OM) and protein leakage analyses further. All three strains showed visible cell damage after LCNEW and LCNEW combined with ultrasound treatment and 1.41 and 1.73 μg/mL of protein leakage were observed for E. coli ATCC 25922 and P. pastoris GS115, respectively after 3 min combination treatment, while 6.22 μg/mL of protein leakage for A. pullulans 2012 after 2 min combination treatment. For biofilms, LCNEW combined with ultrasound also significantly reduced the survival cells both on coupons and in suspension for all three strains. The results suggest that LCNEW combined with ultrasound is a promising approach to sanitise food equipment.     

SiO2胶体探针的制备及其在表面力测定中的应用

采用一种新方法——双向三维移动平台法制备胶体探针，该方法使用两个三雏移动平台，同时将CCD与长工作距离显微镜集成，组成视频监视系统来监控探针的整个制备过程，方便了操作。利用此自组装装置制备的二氧化硅胶体探针在原子力显微镜上进行力曲线测量，将分析数据与Ducker的经典论文进行对照，得到较为理想的结果。     

Wavelength dependent laser-induced etching of Cr-O doped GaAs: Morphology studies by SEM and AFM

The laser induced etching of semi-insulating GaAs 〈100〉 is carried out to create porous structure under super- and sub-bandgap photon illumination (h v). The etching mechanism is different for these separate illuminations where defect states play the key role in making distinction between these two processes. Separate models are proposed for both the cases to explain the etching efficiency. It is observed that under sub-bandgap photon illumination the etching process starts vigorously through the mediation of intermediate defect states. The defect states initiate the pits formation and subsequently pore propagation occurs due to asymmetric electric field in the pore. Formation of GaAs nanostructures is observed using scanning electron (SEM) and atomic force microscopy (AFM).