基于多重分形谱研究十二烷基硫醇分子自组装膜在铜表面的作用行为

采用动电位扫描、原子力显微镜相位测试,基于多重分形谱,研究了十二烷基硫醇分子自组装膜在铜表面的作用行为。结果表明,在氯化钠溶液中,十二烷基硫醇分子自组装膜对铜腐蚀有显著的抑制效果,缓蚀效率随自组装时间的增加而增大。采用原子力显微镜对样品进行相位图测试,基于多重分形谱对相位图进行分析,可反映出随着自组装时间的增加,自组装膜在铜表面从部分覆盖到完全覆盖的过程。     

粗糙薄膜表面的原子力显微镜研究和多重分形分析

用一系列生成元模拟了具有不同特征的、与原子力显微镜图像相似的规则粗糙表面。详细讨论了规则粗糙表面多重分形谱参数的意义。并通过与方均根粗糙度（rms）和简单分形维数D0的比较，描述了多重分形分析的优点。最后用多重分形的方法分析了由AFM测量的ZnO薄膜和高聚物PtBuA薄膜的表面形貌。     

压电传感器电极表面的原位物理化学研究

使用压电传感器原位研究己二硫醇在金表面上的吸附/解吸附液相动力学,从起始阶段到达到吸附平衡,通过线性拟合,表明吸附过程符合Langmuir吸附模型;确定己二硫醇在不同溶剂中,在Au表面吸附/解吸附的速率常数、表观平衡常数、自由能,以及通过在不同温度下的实验结果推导出反应的表观活化能,为压电传感器电极表面自组装提供基本的理论参数。     

基于分子印迹聚合膜的胆固醇丝网印刷生物传感芯片

该文基于自组装技术在丝网印刷金电极表面制备分子印迹膜,研制胆固醇电化学仿生生物传感芯片。利用扫描电镜(SEM)对平面裸金电极、厚膜裸金电极及其修饰电极进行了形貌的分析比较,采用循环伏安分析法对电极修饰过程的电化学特性进行表征,采用计时电流法对胆固醇生物传感芯片的浓度响应特性进行检测。结果表明, 基于丝网印刷工艺的厚膜电极不仅能满足自组装分子印迹仿生膜的修饰,而且电极表面具有明显的纳米放大效应。传感器对0~700 nM不同浓度胆固醇进行检测,线性范围50 nM~700 nM,灵敏度达到-4.94 A/[lg(nM)],线性相关系数为0.994。该胆固醇传感芯片具有较高的准确性,检测准确度达到了99.56%。     

退火态Cu膜表面形貌的分形特征

用磁控溅射工艺在Si基片上沉积500nm厚Cu膜,并在不同温度下进行快速退火处理。用扫描电镜（SEM）与原子力显微镜（AFM）观察薄膜表面形貌,并根据分形理论予以定量表征。结果表明：当退火温度T在小于673K范围内增加时,分形维数Dr逐渐减小;而当T增加至773K时,Dr异常增加。本文根据表面扩散、晶粒长大、缺陷形成等机制对其进行了分析。     

稀土La自组装纳米膜的制备及表征

电子封装表面材料采用分子自组装技术制备了稀土La纳米膜,采用AFM(原子力显微镜)对组装膜的表面形貌进行表征,表征结果该稀土纳米膜表面形貌致密,表面粒子尺寸为20～30nm;场发射扫描电镜测试表明,该组装膜的成分为La;     

分子取向的高分辨率扫描隧道显微术

本文介绍了一种借助于扫描隧道显微镜的空间高分辨能力探测单个分子取向的方法.利用这种方法,我们研究了以下四种体系中的分子取向二维C 60分子阵列;C 60(111)多层膜表面;吸附在Si(111) (7×7)表面的C 60单分子;Au(111)表面的硫醇自组装单分子层膜.结合局域密度近似方法理论计算,我们确定了以上体系中的分子取向.     

检测三磷酸腺苷的交流阻抗型适体传感器

将一端标记具有可逆电化学行为的电活性基团二茂铁、另一端标记巯基的三磷酸腺苷(ATP)适体ss-DNA组装到薄膜金电极上,构筑了一种可灵敏检测ATP浓度的交流阻抗型适体传感器。首先研究了适体传感器的自组装方法,然后利用交流阻抗法研究了适体传感器在铁氰化钾(K3Fe(CN)6)和亚铁氰化钾(K4Fe(CN)6)混合溶液中的电极表面电子传递阻抗和被测物ATP浓度之间的关系,最后对自组装的阻抗型适体传感器的电化学特性进行了分析。实验表明:利用自组装的适体传感器检测ATP浓度时,适体传感器检出限低,线性检测范围宽,重复性好,其中检出限为0.5μmol/L,线性检测范围为0.5~100μmol/L,线性度为0.998 9,连续5次测量的相对标准差为1.5%。     

不同衬底上溅射Cu膜的表面形貌

采用磁控溅射工艺在石英、云母与Ti/Si衬底上制备100 nm厚Cu膜,并在300℃条件下进行原位退火.用原子力显微镜(AFM)观察薄膜表面形貌,基于粗糙度方法与分形理论对其量化表征.结果表明:分形维数Di比粗糙度Rrms更能准确地表征薄膜表面几何形态;石英衬底上Cu膜具有较为复杂的表面结构,其Df值大于沉积在云母和Ti/Si衬底上薄膜的;经过退火处理后,所有薄膜的表面形貌均趋于平滑化,Df值减小.     

30CrMnSi断口表面的分形特征

３０ＣｒＭｎＳｉ断口表面的分形特征周善民王伟兰胡小波（南昌航空工业学院，南昌３３００３４）断口表面是粗糙的和不规则的，具有近似的自相似性质，可以看成是一种分形结构，分形维数Ｄ是断裂表面分形结构时粗糙度的一种度量。选用３０ＣｒＭｎＳｉ合金钢为研究对象，...     

Suppressive effect of a self-assembled monolayer on the polycrystallization of naphthyl-substituted diamine derivative thin film

We observed the polycrystallization process of a naphthyl-substituted diamine derivative (NPD) thin film on a self-assembled monolayer (SAM)-modified indium–tin–oxide (ITO) substrate. Fluorine-substituted SAM suppressed the growth of the polycrystalline region. After estimating the surface morphology of the polycrystalline region using AFM measurement, correlation between the molecular migration rate on the substrate, the rearrangement rate at the growth point, and the provision rate from the amorphous region clarified the polycrystallization growth mechanism for the NPD thin film. The formation of a channel around the polycrystalline region and the molecular migration rate on the substrate play important roles in polycrystalline region growth.     

Observation on Surface and Cross Section of Thin Film Solar Cells Using Atomic Force Microscope

Atomic force microscope (AFM) is able to produce thrce-dimensional digital data in both force-mode and heightmode and its applications are not limited to map the surfaces of conducting materials. It can use the force-mode to image the repulsive and attractive force patterns. The cross sections of polycrystalline CdS/CdTe and amorphous silicon heterojunction solar cells are observed with AFM. In case of short circuit, the microstructures of different layers in the samples are clearly displayed. When the cells are open circuit, the topographical images are altered, the potential outline due to the space charge in junction region is observed. Obviously, AFM can be employed to investigate experimentally built-in potential in junction of semiconductor devices, such as solar cells.     

Thickness‐Dependent Structural Evolutions and Growth Models in Relation to Carrier Transport Properties in Polycrystalline Pentacene Thin Films

Thickness‐dependent crystal structure, surface morphology, surface energy, and molecular structure and microstructure of a series of polycrystalline pentacene films with different film thickness ranging from several monolayers to the several hundred nanometers have been investigated using X‐ray diffraction (XRD), atomic force microscopy (AFM), contact angle meter, and Raman spectroscopy. XRD studies indicate that thin film polymorphs transformation behaviours are from the orthorhombic phase to the thin‐film phase and then to the triclinic bulk phase as measured by the increased tilt angle (θ_tilt) of the pentacene molecule from the c‐axis toward the a‐axis. We propose a growth model that rationalizes the θ_tilt increased along with increasing film thickness in terms of grain size and surface energy varying with film growth using AFM combined with contact angle measurements. The vibrational characterizations of pentacene molecules in different thickness films were investigated by Raman spectroscopy compared to density functional theory calculations of an isolated molecule. In combination with XRD and AFM the method enables us to distinguish the molecular microstructures in different thin film polymorphs. We proposed a methodology to probe the microscopic parameters determining the carrier transport properties based on Davydov splitting and the characteristics of aromatic C–C stretching modes in Raman spectra. When compared to the triclinic bulk phase at a high thickness, we suggest that the first few monolayer structures located at the dielectric surface could have inferior carrier transport properties due to weak intermolecular interactions, large molecular relaxation energy, and more grain boundaries.     

PECVD制备纳米晶多晶硅薄膜

以Si(100)为衬底,采用磁控溅射和射频等离子体增强化学气相沉积系统制备了Si(100)/Al膜/非晶Si膜结构的样品。对该样品进行Al诱导真空退火以制备多晶硅薄膜,采用X射线衍射仪(XRD)和AFM分析薄膜微结构及表面形貌。实验结果表明,在经过500℃、550℃Al诱导退火后,形成了择优取向为〈111〉晶向的多晶硅薄膜。AFM给出了550℃退火后薄膜表面形貌,为100～200nm大小的圆丘状硅晶粒,密集排列在薄膜表面;并对Al诱导真空退火晶化的机理进行了分析。     

多晶硅薄膜晶体管自加热效应温度分布的有限元模拟

采用有限元方法模拟了n型MILC低温多晶硅薄膜晶体管在直流自加热应力下器件的温度分布．通过对器件沟道温度分布的稳态及瞬态模拟,研究了器件功率密度、衬底材料类型和器件宽长等关键因素的影响．确认了改善器件自加热退化的有效途径,同时有助于揭示多晶硅薄膜晶体管自加热退化的内在机制．     

Optical and microstructural characterization of the effects of rapid thermal annealing of CdTe thin films grown on Si (100) substrates

The effects of rapid thermal annealing (RTA) on CdTe/Si (100) heterostructures have been studied in order to improve the structural quality of CdTe epilayers. Samples of CdTe (111) polycrystalline thin films grown by vapor phase epitaxy (VPE) on Si (100) substrates have been investigated. The strained structures were rapidly thermally annealed at 400°C, 450°C, 500°C, 550°C, and 600°C for 10 sec. The microstructural properties of the CdTe films were characterized by carrying out scanning electron microscopy (SEM), x-ray diffraction (XRD), and atomic force microscopy (AFM). We have shown that the structural quality of the CdTe epilayers improves significantly with increasing annealing temperature. The optimum annealing temperature resulting in the highest film quality has been found to be 500°C. Additionally, we have shown that the surface nucleation characterized by the island size distribution can be correlated with the crystalline quality of the film.     

Formation of a step-free InAs quantum well selectively grown on a GaAs (111)B substrate

We investigated the possibility of forming a step-free quantum well structure. A step-free InAs monolayer was grown on a selectively grown mesa by controlling surface phases with in-situ monitoring of surface photo-absorption. We selectively grew a GaAs buffer at 800°C and cooled the sample keeping the (2×2)-like As stabilized surface. Atomic force microscopy (AFM) observation demonstrated that fully step-free surfaces were formed on the 8 μm wide mesa. Then, a monolayer-thick InAs was formed on this step-free surface and this InAs layer was capped by GaAs under the (2×2)-like condition. The quantum level of the step-free InAs layer was evaluated by spatially resolved photoluminescence (μPL) measurement. Uniform PL intensity and the lack of a double layer peak indicated the formation of a step-free InAs quantum well, which was in good agreement with AFM observation.     

Optimization of physical properties of vacuum evaporated CdTe thin films with the application of thermal treatment for solar cells

This paper reports the optimization of physical properties of cadmium telluride (CdTe) thin films with the application of thermal treatment. The films of thickness 650 nm were deposited on glass and indium tin oxide (ITO) coated glass substrates employing vacuum evaporation followed by thermal annealing in the temperature range 250–450 °C. The films were characterized using X-ray diffraction (XRD), source meter and atomic force microscopy (AFM) for structural, electrical and surface topographical properties respectively. The X-ray diffraction patterns reveal that films are polycrystalline with predominant zinc-blende structure having preferred reflection (111). The structural parameters are calculated and discussed in detail. The current–voltage characteristics show Ohmic behavior and the electrical conductivity is found to increase with annealing treatment. The AFM studies show that the surface roughness of films is observed to increase with annealing. The experimental results reveal that the thermal annealing plays an important role to enhance the physical properties of CdTe thin films and annealed films may be used as absorber layer in CdTe/CdS solar cells.     

低温下应变外延层的单层生长

用接触式原子力显微镜来观察460℃低温下生长的In0.35Ga0.65As/GaAs外延层形貌.实验发现,这种460℃低温生长材料的失配外延层既不是层状的FvdM生长模式也不是岛状的SK自组织生长模式,而是由原子单层构成的梯田状大岛.原子力显微镜测试表明台阶的厚度为0.28nm,约为一个原子单层,这种介于层状和岛状生长之间的模式有助于了解失配异质外延的生长过程.     

自组装金纳米粒子薄膜AFM研究

以化学还原法制备了金胶体,采用静电吸附自纽装法在单晶硅片表面制备了金纳米粒子薄膜,采用原子力显微镜分析了薄膜的表面形貌与结构。