Dissertations / Theses: 'Scanning probe microscopy. Nanoscience'

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Gcwabaza, Thabo. "Scanning probe microscopy and oxidation of silicon at breakdown voltages." Huntington, WV : [Marshall University Libraries], 2006. http://www.marshall.edu/etd/descript.asp?ref=722.

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McCausland, Jeffrey A. "Select Applications of Scanning Probe Microscopy to Group XIV Surfaces and Materials." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1510327417528433.

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Hanyu, Yuki. "Chemical scanning probe lithography and molecular construction." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:409308ed-4806-44fc-87c3-5c1fe8971f79.

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The initiation and high resolution control of surface confined chemical reactions would be both beneficial for nanofabrication and fundamentally interesting. In this work, spatially controlled scanning probe directed organometallic coupling, patterned functional protein immobilisation and highly localised reversible redox reactions on SAMs were investigated. Catalytically active palladium nanoparticles were mounted on a scanning probe and an appropriate reagent SAM was scanned in a reagent solution. This instigated a spatially resolved organometallic coupling reaction between the solution and SAM-phase reagents. Within this catalytic nanolithography a spatial resolution of ~10nm is possible, equating to zeptomole-scale reaction. The methodology was applied to reactions such as Sonogashira coupling and local oligo(phenylene vinylene) synthesis. By altering the experimental protocols, relating probe scan velocity to reaction yield and characterising the nanopattern, a PVP matrix model describing a proposed mechanism of catalytic nanolithography, was presented. Though ultimately limited by probe deactivation, calculations indicated that activity per immobilised nanoparticle is very high in this configuration. For biopatterning, surface nanopatterns defined by carboxylic functionality were generated from methyl-terminated SAMs by local anodic oxidation (LAO) initiated by a conductive AFM probe. By employing suitable linker compounds, avidin and Stefin-A quadruple Mutant (SQM) receptive peptide aptamers were patterned at sub-100nm resolution. The multiplexed sensing capability of an SQM array was demonstrated by reacting generated patterns with single or a mixture of multiple antibodies. The reversible redox conversion and switching of reactivity of hydroquinone-terminated SAMs was electrochemically demonstrated prior to an application in redox nanolithography. In this methodology, spatially controlled probe-induced in situ "writing" and "erasing" based on reversible redox conversion were conducted on hydroquinone terminated SAM. In combination with dip-pen nanolithography, a novel method of redox electro-pen nanolithography was designed and the method’s application for lithography was examined.

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Ferguson, Josephus Daniel III. "Investigation of Surface Properties for Ga- and N-polar GaN using Scanning Probe Microscopy Techniques." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3089.

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Because the surface plays an important role in the electrical and optical properties of GaN devices, an improved understanding of surface effects should help optimize device performance. In this work, atomic force microscopy (AFM) and related techniques have been used to characterize three unique sets of n-type GaN samples. The sample sets comprised freestanding bulk GaN with Ga polar and N polar surfaces, epitaxial GaN films with laterally patterned Ga- and N-polar regions on a common surface, and truncated, hexagonal GaN microstructures containing Ga-polar mesas and semipolar facets. Morphology studies revealed that bulk Ga-polar surfaces treated with a chemical-mechanical polish (CMP) were the flattest of the entire set, with rms values of only 0.4 nm. Conducting AFM (CAFM) indicated unexpected insulating behavior for N-polar GaN bulk samples, but showed expected forward and reverse-bias conduction for periodically patterned GaN samples. Using scanning Kelvin probe microscopy, these same patterned samples demonstrated surface potential differences between the two polarities of up to 0.5 eV, where N-polar showed the expected higher surface potential. An HCl cleaning procedure used to remove the surface oxide decreased this difference between the two regions by 0.2 eV. It is possible to locally inject surface charge and measure the resulting change in surface potential using CAFM in conjunction with SKPM. After injecting electrons using a 10 V applied voltage between sample and tip, the patterned polarity samples reveal that the N-polar regions become significantly more negatively charged as compared to Ga-polar regions, with up to a 2 eV difference between charged and uncharged N polar regions. This result suggests that the N-polar regions have a thicker surface oxide that effectively stores charge. Removal of this oxide layer using HCl results in significantly decreased surface charging behavior. A phenomenological model was then developed to fit the discharging behavior of N-polar GaN with good agreement to experimental data. Surface photovoltage (SPV) measurements obtained using SKPM further support the presence of a thicker surface oxide for N polar GaN based on steady state and restoration SPV behaviors. Scanning probe microscopy techniques have therefore been used to effectively discriminate between the surface morphological and electrical behaviors of Ga- vs. N-polar GaN.

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Doutt, Daniel R. "THE ROLE OF NATIVE POINT DEFECTS AND SURFACE CHEMICAL REACTIONS IN THE FORMATION OF SCHOTTKY BARRIERS AND HIGH N-TYPE DOPING IN ZINC OXIDE." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366199639.

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Almqvist, Nils. "Scanning probe microscopy : Applications." Licentiate thesis, Luleå tekniska universitet, Materialvetenskap, 1994. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17980.

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DjuricÌŒicÌŒ, Dejana. "Biological scanning probe microscopy (SPM)." Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403609.

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Pinheiro, Lucidalva dos Santos. "Scanning probe microscopy of adsorbates." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320589.

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Howells, Samuel Charles. "Surface studies with scanning probe microscopy." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/185905.

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Using scanning probe microscopy, several studies were carried out to characterize surface topographies and properties. First, utilizing scanning tunneling microscopy (STM), we characterized fullerenes deposited onto gold foils and highly oriented gold films. On gold foils, we found that C₆₀ packed in hexagonally ordered overlayers and that the images showed internal buckyball features that arose from electronic interactions between the molecule and the substrate. On gold films, with an ordered overlayer of methyl isobutyl ketone (MIBK), the isolated C₆₀ molecules showed internal features in a "doughnut" shape, different than those seen previously. We also imaged gold foils on which a significant number of larger fullerene molecules were deposited, and found only spherical molecules in our images. A theoretical analysis of the optical beam deflection atomic force microscope (AFM) predicted sufficient sensitivity to measure atomic corrugations greater than 1 A. This agreed with experimental results showing atomically resolvable images. Another theoretical investigation probe the relative magnitude of the forces between the tip, sample, and an adsorbed atom on a surface. Experimentally, we investigated cleaved multiple quantum wells ans showed surface corrugations with a period equal to the quantum well spacing. The third technique used was magnetic force microscopy (MFM). We analyzed a novel system that combined the tunneling aspects of STM with the force-sensing attributes of force microscopy, and provided the ability to simultaneously image surface features as well as magnetic domains with a sensitivity that depended on the spring constant of the tunneling tip. Experimentally, we used this system to image magnetic domains and reveal the surface roughness of magnetic recording media. The second MFM technique involved spin-coating a magnetic surface with a ferrofliud, then over-coating with gold, and finally imaging the surface with STM. The STM revealed raised ridges where the ferromagnetic particles clumped in regions of high magnetic field gradient. The finally MFM we utilized imaged magnetic fields using a beam deflection force microscope by modulating a magnetic disk head and detecting the vibration of the magnetic tip. We were able to image the fields of a floppy disk head.

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Liou, Je-Wen. "Scanning probe microscopy of photosynthetic membranes." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398112.

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Williams, P. M. "Computational studies in scanning probe microscopy." Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294243.

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Bond, Stephen Francis. "Scanning probe microscopy of conjugated polymers." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339756.

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Chen, Qian. "Scanning probe recognition microscopy recognition strategies /." Diss., Connect to online resource - MSU authorized users, 2007.

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Thesis (Ph. D.)--Michigan State University. Dept. of Electrical & Computer Engineering, 2007.
Title from PDF t.p. (viewed on Apr. 21, 2009) Includes bibliographical references (p. 123-129). Also issued in print.

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Eves, Brian John. "Scanning probe energy loss spectroscopy." Thesis, University of Birmingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251871.

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Mukhopadhyay, Rupa. "Scanning probe microscopy of functionalised metal surfaces." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343521.

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Mullin, Nicholas William. "Dynamic Imaging Methods for Scanning Probe Microscopy." Thesis, University of Sheffield, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.521859.

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余家訓 and Ka-fan Yu. "Scanning probe microscopy of porous silicon formation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31222110.

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Kohlgraf-Owens, Dana. "Optically Induced Forces in Scanning Probe Microscopy." Doctoral diss., University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5649.

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The focus of this dissertation is the study of measuring light not by energy transfer as is done with a standard photodetector such as a photographic film or charged coupled device, but rather by the forces which the light exerts on matter. In this manner we are able to replace or complement standard photodetector-based light detection techniques. One key attribute of force detection is that it permits the measurement of light over a very large range of frequencies including those which are difficult to access with standard photodetectors, such as the far IR and THz. The dissertation addresses the specific phenomena associated with optically induced force (OIF) detection in the near-field where light can be detected with high spatial resolution close to material interfaces. This is accomplished using a scanning probe microscope (SPM), which has the advantage of already having a sensitive force detector integrated into the system. The two microscopies we focus on here are atomic force microscopy (AFM) and near-field scanning optical microscopy (NSOM). By detecting surface-induced forces or force gradients applied to a very small size probe ( diameter), AFM measures the force acting on the probe as a function of the tip-sample separation or extracts topography information. Typical NSOM utilizes either a small aperture ( diameter) to collect and/or radiate light in a small volume or a small scatterer ( diameter) in order to scatter light in a very small volume. This light is then measured with an avalanche photodiode or a photomultiplier tube. These two modalities may be combined in order to simultaneously map the local intensity distribution and topography of a sample of interest. A critical assumption made when performing such a measurement is that the distance regulation, which is based on surface induced forces, and the intensity distribution are independent. In other words, it is assumed that the presence of optical fields does not influence the AFM operation. However, it is well known that light exerts forces on the matter with which it interacts. This light-induced force may affect the atomic force microscope tip-sample distance regulation mechanism or, by modifying the tip, it may also indirectly influence the distance between the probe and the surface. This dissertation will present evidence that the effect of optically induced forces is strong enough to be observed when performing typical NSOM measurements. This effect is first studied on common experimental situations to show where and how these forces manifest themselves. Afterward, several new measurement approaches are demonstrated, which take advantage of this additional information to either complement or replace standard NSOM detection. For example, the force acting on the probe can be detected while simultaneously extracting the tip-sample separation, a measurement characteristic which is typically difficult to obtain. Moreover, the standard field collection with an aperture NSOM and the measurement of optically induced forces can be operated simultaneously. Thus, complementary information about the field intensity and its gradient can be, for the first time, collected with a single probe. Finally, a new scanning probe modality, multi-frequency NSOM (MF-NSOM), will be demonstrated. In this approach, the tuning fork is driven electrically at one frequency to perform a standard tip-sample distance regulation to follow the sample topography and optically driven at another frequency to measure the optically induced force. This novel technique provides a viable alternative to standard NSOM scanning and should be of particular interest in the long wavelength regime, e.g. far IR and THz.
Ph.D.
Doctorate
Optics and Photonics
Optics and Photonics
Optics

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Yu, Xi. "Multi-mode low temperature scanning probe microscopy." Thesis, University of Nottingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404031.

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Thomson, Neil Henderson. "Scanning probe microscopy of seed-storage components." Thesis, University of Bristol, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240462.

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James, Paul John. "Scanning probe microscopy of perfluorinated ionomer membranes." Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322363.

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Pan, Tianluo. "Scanning probe microscopy of poly-atomic molecules." Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4001/.

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This thesis presents studies on the adsorption of chlorobenzene using STS, non-local desorption of chlorobenzene and the atomic manipulation of the PCB molecule using STM. The atomic manipulation of the mucin molecule on HOPG surfaces under different conditions has also been investigated. Chlorobenzene adsorbate on the Si(111)-(7×7) surface has been investigated using STS. The missing rest atom state at -0.8 V confirmed the rest atom involvement in the bonding geometry. Two adsorbate states located at -1.3 V and +1 to +2 V have been identified. The effect of the surface step and the temperature on the non-local chlorobenzene desorption process has been investigated. Different reactions generated by STM of the PCB molecule on the Si(111)-(7×7) surface have been studied. While molecular desorption is maximized by electron injection into the chemisorbed molecular ring at low voltage, injection into the physisorbed molecular ring at high voltage favours the reconfiguration of the bonding. The mucin molecule has been studied by AFM and STM. An unraveling manipulation has been achieved over a folded mucin polymer on the bare HOPG surface. Enhanced mucin-substrate binding has also been achieved in the liquid state on the size-selected Au55 cluster-decorated HOPG surface.

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Paul, William. "Atomically defined tips in scanning probe microscopy." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=119374.

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Scanning probe microscopy (SPM) studies are carried out with atomically defined tips, characterized by field ion microscopy (FIM). This combination of microscopies allows for the characterization of the SPM probe apex which is usually of unknown atomic geometry – in principle, an atomically defined tip would predetermine SPM resolution and the tip's electronic structure for spectroscopy. In a set of exploratory experiments to investigate the use of atomically defined tips in SPM, we investigate issues of tip integrity, material transfer and tip modifications, and implement the tips in the study of mechanical properties of nanoscale contacts by indentation. In order to perform SPM studies with the characterized tips, a protocol is introduced to preserve the atomic structure of the tip apex from etching due to gas impurities during the transfer period from FIM to SPM. Estimations are made regarding the time limitations of such an atomically-defined experiment due to contamination by ultra-high vacuum (UHV) rest gases. We conclude from tunneling experiments with several types of surfaces that transferred atoms from the sample limit the choice of surfaces for which the tip integrity is preserved in tunneling experiments at room temperature. The atomic structure of FIM tip apices is unchanged only after tunneling to the highly reactive Si(111) surface. Atoms transferred to W(111) and W(110) tip apices from the Au(111) surface during tunneling and approach to contact experiments are characterized in FIM at room temperature and at 158 K. The different activation energies for diffusion on the (111) and (110) tip planes and the experiment temperature are shown to be important considerations in observing changes to the atomic structure of the tip in FIM. Resolution of atomically defined tips in scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) is investigated on the Si(111)-2×1 surface, but tip integrity remains a challenge even for this substrate at room temperature. In spite of changes to the atomic structure of tip apices, FIM-characterized SPM tips are very well suited to the study of nanoscale plasticity in atomic-scale nanoindentation. Accurate characterization of the probe tip is required for estimating contact stresses and is also used as input for atomistic simulations on the same size scale. We investigate unique phenomena in mechanical contacts between dissimilar metals with clean FIM tips, then the formation of the smallest permanent indentation on the Au(111) surface is studied at the transition of elastic to plastic loading. Nanoindentation and characterization of the plastic damage to the surface are accomplished by simultaneous STM and atomic force microscopy (AFM) with a 9.5 nm radius W(111) tip. Elastic and plastic indentations are identified both in the residual impression image and by features in their force-displacement curves such as the sink-in depth, pop-ins and hysteresis energy. Plasticity is best identified quantitatively in the force-displacement curves by the sink-in depth. The minimum 'quantum' of plastic damage to the substrate is associated with an energy budget of ~70 eV.In summary, we have introduced a protocol for implementing atomically defined tips in SPM experiments and explored the limitations in preserving the integrity of the tip. We conclude that within the constraints of room temperature experiments on metal surfaces, their use in atomic-scale nanoindentation experiments is still extremely valuable.
Des études de microscopie à sonde locale (scanning probe microscopy, SPM) sont effectuées à l'aide de pointes définies à l'échelle atomique caractérisées par microscopie à champ ionique (field ion microscopy, FIM). La combinaison de ces microscopies permet de caractériser la géométrie, généralement inconnue, des atomes situés à la pointe d'une sonde SPM. En principe, cette information détermine la résolution de la SPM ainsi que la structure électronique de la pointe en spectroscopie. Une séquence d'expériences exploratoires en SPM utilisant ces pointes, permet d'étudier les problèmes reliés au maintient de leur intégrité, au transfert de matériel et à leur modification. Ces pointes sont ensuite utilisées lors d'expériences d'indentation afin d'étudier les propriétés mécaniques des contacts à l'échelle nanométrique. Afin de réaliser des études de SPM avec des pointes définies, un protocole est développé pour protéger la structure atomique des pointes contre les attaques chimiques par des impuretés gazeuses, lors de leur transfert du FIM au SPM. Une fois dans un ultra haut vide (UHV), ces expériences sont soumises à des contraintes de temps dû à l'éventuelle contamination des pointes par des gaz résiduels. Une estimation de ces contraintes est présentée. À partir d'expériences de jonction tunnel effectuées sur différents types de surface, nous observons que pour plusieurs d'entre elles, le transfert d'atome de l'échantillon à la pointe ruine l'intégrité de la sonde à température ambiante. Cela limite grandement le choix des matériaux pour ce type d'expérience. Dans nos expériences, la structure atomique des pointes imagées par FIM reste inchangée seulement dans le cas de la surface très réactive Si(111). La résolution obtenue avec ces pointes en microscopie à effet tunnel (MET) et en spectroscopie par effet tunnel (scanning tunneling spectroscopy, STS) est étudiée sur une surface Si(111)-2×1. Même pour ce substrat, la préservation de l'intégrité de la pointe à température ambiante demeure un défi. En dépit des changements qui modifient la structure atomique des pointes lors d'une expérience, ces sondes caractérisées par FIM sont intéressantes pour l'étude de la plasticité à l'échelle nanométrique par nano-indentation. Une caractérisation exacte de la pointe de la sonde est nécessaire pour estimer le tenseur des contraintes associé à un contact mécanique et permet de déterminer les paramètres d'entrées pour des simulations atomistiques. L'observation d'un nouveau phénomène lors d'un contact mécanique entre différents métaux et des pointes propres caractérisées par FIM est présentée. La formation de la plus petite indentation permanente sur une surface d'or Au(111) est étudiée à la transition entre les régimes de déformation élastique et plastique. La nano-indentation et la caractérisation de la déformation plastique sur la surface sont réalisées par une mesure simultanée de microscopie à effet tunnel (MET) et de microscopie à force atomique (MFA) avec une pointe de W(111) de 9.5 nm de rayon. Les indentations plastiques et élastiques sont identifiées à l'aide des images des impressions résiduelles ainsi que par les caractéristiques des courbes de force-déplacement, telles que la profondeur de sink-in, les pop-ins et l'énergie d'hystérésis. La plasticité s'identifie mieux par une analyse quantitative de la profondeur de sink-in dans les courbes de force-déplacement. Le "quanta" de la plus petite déformation plastique sur un substrat est associé à une énergie d'environ 70 eV.En résumé, nous avons développé un protocole pour implémenter des pointes définis à l'échelle atomique pour des expériences de SPM et nous avons exploré les limitations associées à la préservation de leur intégrité. Nous concluons que malgré les contraintes reliées à leur usage à température ambiante, ces pointes demeurent néanmoins très intéressantes pour des expériences de nano-indentations.

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Chiesa, Marco. "Scanning Kelvin probe microscopy of organic devices." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613074.

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Sumner, Joy. "Scanning probe microscopy studies on Gallium nitride." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612451.

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Gustafsson, Alexander. "Modeling of non-equilibrium scanning probe microscopy." Licentiate thesis, Linnéuniversitetet, Institutionen för fysik och elektroteknik (IFE), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-46448.

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The work in this thesis is basically divided into two related but separate investigations. The first part treats simple chemical reactions of adsorbate molecules on metallic surfaces, induced by means of a scanning tunneling probe (STM). The investigation serves as a parameter free extension to existing theories. The theoretical framework is based on a combination of density functional theory (DFT) and non-equilibrium Green's functions (NEGF). Tunneling electrons that pass the adsorbate molecule are assumed to heat up the molecule, and excite vibrations that directly correspond to the reaction coordinate. The theory is demonstrated for an OD molecule adsorbed on a bridge site on a Cu(110) surface, and critically compared to the corresponding experimental results. Both reaction rates and pathways are deduced, opening up the understanding of energy transfer between different configurational geometries, and suggests a deeper insight, and ultimately a higher control of the behaviour of adsorbate molecules on surfaces. The second part describes a method to calculate STM images in the low bias regime in order to overcome the limitations of localized orbital DFT in the weak coupling limit, i.e., for large vacuum gaps between a tip and the adsorbate molecule. The theory is based on Bardeen's approach to tunneling, where the orbitals computed by DFT are used together with the single-particle Green's function formalism, to accurately describe the orbitals far away from the surface/tip. In particular, the theory successfully reproduces the experimentally well-observed characteristic dip in the tunneling current for a carbon monoxide (CO) molecule adsorbed on a Cu(111) surface. Constant height/current STM images provide direct comparisons to experiments, and from the developed method further insights into elastic tunneling are gained.

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Attwood, Simon. "Nanoscale chemical specification using scanning probe techniques." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608912.

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Lepidis, Polichronis. "High resolution frequency analysis in scanning probe microscopy." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=96834674X.

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Xue, Jiamin. "Scanning Probe Microscopy of Graphene and Carbon Nanotubes." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/238911.

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This dissertation presents research on scanning probe microscopy and spectroscopy of graphene and carbon nanotubes. In total three experiments will be discussed. The first experiment uses a scanning tunneling microscope (STM) to study the topographic and spectroscopic properties of graphene on hexagonal boron nitride (hBN). Graphene was first isolated and identified on SiO₂ substrates, which was later found to be the source of graphene quality degradation, e.g. large surface roughness, increased resistivity and random doping etc. Researchers have been trying to replace SiO₂ with other materials and hBN is by far the most successful one. Our STM study shows an order of magnitude reduction in surface roughness and electrostatic potential variation compared with graphene on SiO₂.The second experiment shows a novel quantum interference effect of electron waves in graphene, loosely referred to as "Friedel oscillations." These arise when incident electron waves interfere with waves scattered from defects in the sample. This interference pattern shows up as a spatial variation in the local density of states, which can be probed by the STM. We measured such Friedel oscillations in graphene near step edges of hBN. Due to its peculiar band structure, the oscillations in graphene have a faster decay rate and their wavelength is an order of magnitude longer than similar oscillations previously observed on noble metal surfaces. By measuring the dependence of the Friedel oscillations on electron energy, we map out the band structure of graphene. The last experiment studies a different system: carbon nanotube quantum dots. By combining scanning probe microscopy and transport measurements, we obtain spatial information about quantum dots formed in a carbon nanotube field effect transistor. We also demonstrate the ability to tune the coupling strength between two quantum dots in series.

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Ozcan, Onur. "Tip Based Automated Nanomanipulation using Scanning Probe Microscopy." Research Showcase @ CMU, 2012. http://repository.cmu.edu/dissertations/155.

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The promise to build structures atom by atom that would lead to devices or materials with tuned properties that surpass any material we encounter in the macroscale world inspires more researchers everyday to study nanotechnology. As a direct result of this interest in nanotechnology, manipulation systems with nano or sub-nano scale precision are required to position or pattern matter in smaller scales to study it. However, this manipulation task is not straightforward due to small scale physics, which reduces the effect of weight and inertia, the dominant forces in macroscale, and promotes other forces such as adhesion or electrostatic interactions. Hence, to understand nanoscale physics, the first step to take is to model and characterize the underlying principles. In this context, scanning probe microscopes (SPMs) are suitable tools for experimenting on nanoscale physics, in addition to being good candidates as nanomanipulation systems due to their ability to locally interact with the substrate using the end-effector that they utilize on the order of a few nanometers or below. On the other hand, using SPMs for nanomanipulation has drawbacks as well. Since they utilize a single end-effector to interact with the substrate, the manipulation process is serial hence slow with low throughput. Furthermore, having no real-time visual feedback and the non-linearity of the actuators decrease the precision and the repeatability of the positioning, hence decreasing the reliability of the manipulation. In order to consider SPMs as viable nanomanipulation tools, these challenges of speed and reliability should first be tackled by utilizing smarter algorithms and mechanisms. In this work, we demonstrate two case studies that are used for tackling the speed and reliability challenges of nanomanipulation. As the first case study, an AFM is utilized to position nanoparticles. In the AFM based mechanical contact manipulation of nanoparticles, we demonstrate automated control to increase speed and reliability. In order to achieve the automation, we present models to investigate the physics of nanoparticle manipulation using an AFM cantilever, and use these models to investigate the effect of cantilever selection to manipulation success. We demonstrate particle detection using line-scans and a contact loss detection algorithm using cantilever normal deflection data to decrease the number of images taken during manipulation. We also demonstrate through experimental results that it is possible to push and pull particles on a flat surface into defined patterns autonomously, using an AFM probe tip, and with an error less than the particle diameter, and with success rates as high as 87%. Moreover, an STM is utilized to manipulate surfaces using electrical pulses and high electric fields as a second case study of this thesis. During the STM based electrical non-contact manipulation, utilizing conductive AFM probes as STM end-effectors as a step towards a multiple probe approach is suggested to improve the speed and throughput of the STM manipulation. STM imaging of surfaces using STM tips and conductive AFM probes are demonstrated and algorithms for STM based electrical manipulation of surfaces is presented and experimentally verified. Furthermore, models for STM operation and manipulation using STM tips and AFM probes as end-effectors are developed and the effects of several design parameters on STM based imaging and manipulation that utilizes AFM probes and STM tips are investigated. In addition, a faster and more flexible controller is designed and implemented which allows instant switching between AFM and STM modes, when conductive AFM probes are utilized.

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Nugues, Steven. "Study of porous materials by scanning probe microscopy." Thesis, University of Southampton, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243090.

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Brayshaw, Debra Jane. "Scanning probe microscopy studies of glycoconjugate molecular interactions." Thesis, University of Bristol, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409424.

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Song, Mi Yeon. "Microfabrication of silicon tips for scanning probe microscopy." Thesis, University of Birmingham, 2009. http://etheses.bham.ac.uk//id/eprint/482/.

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This thesis investigates the microfabrication of silicon tips for Scanning Probe Microscopy. First, a microfabrication process was developed to produce silicon tips over 100 um height with a sharp apex of ~10–20 nm. To prevent inadvertent contact between the substrate bearing the tip and the sample being probed, the tip is elevated on a mesa structure. Atomic resolution STM images of graphite are successfully obtained using silicon tips. Subsequently, a co-axial tip was developed for SPELS. SPELS uses an STM tip in field emission mode and then analyses the energy of electrons backscattered. However, the electric field distorts the trajectories of the backscattered electrons. A screened co-axial tip was thus designed; the tip consists of a multilayer Si/Au/HfO\(-2\)/Au structure. The outermost Au layer is grounded. SPELS spectra of graphite were successfully obtained for the first time. Third, a multilayered tip was fabricated for the Scanning Probe Electron AnalyseR.. This approach is a combination of STM with an ultraviolet light source. The designed structure is a multilayered silicon tip consisting of Si/SiO\(_2\)/Au/SiO\(_2\)/Au; the three conducting layers act as an electron collector, retarding field analyser, and grounded shield layer, respectively.

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Richards, Owen James. "Advances in scanning ion conductance microscopy." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648409.

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Beyer, Matthieu. "Elaborations et caractérisations d'auto-assemblages dipolaires par microscopie à effet tunnel." Thesis, Besançon, 2015. http://www.theses.fr/2015BESA2056/document.

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Ce travail de thèse est consacré à l’étude d’auto-assemblages de molécules organiques π-conjuguées par microscopie à effet tunnel (STM)sous ultra-vide sur une surface de silicium dopée bore. Le manuscrit est constitué de cinq chapitres : dans le premier chapitre, nous présentons un état de l’art des assemblages organiques sur les surfaces métalliques et sur les semi-conducteurs. Le chapitre deux décrit le dispositif expérimental utilisé au cours de cette thèse. Il présente également le substrat de Si(111)-B et fournit les concepts théoriques associés à la microscopie à effet tunnel. Le troisième chapitre décrit en détail les réseaux supramoléculaires obtenus à partir d’une molécule aromatique halogénée de symétrieC2. L’adsorption de 4,4"-dibromo-p-terphényle conduit à la formation de deux types de structures compactes (l’une en bande et l’autre en chevron) stables à température ambiante et commensurables avec la surface. Nous montrons que ces architectures sont pilotées conjointement par la liaison hydrogène, la liaison halogène et du π -stacking. Le quatrième chapitre étudie l’influence du nombre de cycles aromatiques sur la géométrie et la périodicité d’auto-assemblages obtenus sur Si (111) -B. Pour cela, nous avons synthétisé deux molécules organiques composées d’une partie centrale aromatique et de deux chaînes latérales (O-(CH2)9-CH3). La partie centrale est constituée respectivement de trois ou cinq cycles phényles terminées par des groupements cyano. Nous nous sommes également intéressés à l’influence des groupements terminaux sur l’organisation du réseau. Nous montrons que l’effet des groupements cyano sur les interactions "molécule/molécule" et sur les interactions "molécule/surface" est négligeable. A partir des travaux obtenus dans le chapitre 4, nous concluons notre manuscrit en présentant des réseaux supramoléculaires de molécules dipolaires. Ces réseaux forment des lignes de dipôles. Nous montrons que sur de petites échelles les molécules favorisent un alignement de leurs moments dipolaires
This work is dedicated to the investigation under ultra high vacuum of _-conjugated molecule on a silicon surface by means of scanningtunneling microscopy (STM). The manuscript consists of five chapters.In the first chapter, we present a state-of-the-art of organic assembly on metal and semiconductor.Chapter two describes the experimental setup using during thesis. It also shows Si(111)-B substrate and gives theoretical conceptsassociated with the scanning tunneling microscopy.The third chapter describes in detail the supramolecular network obtained from an aromatic halogenated molecule with C2 symmetry. Theadsorption of 4,4"-dibromo-p-terphenyl leads to the formation of two kinds of compacts structures (a stripe structure and a herringbonestructure). The formed networks are stable at room temperature and commensurable with the surface. These architectures are promotedby hydrogen bond, halogen bond and _-stacking.Chapter four studies influence of benzene ring number on the geometry and the periodicity of self-assemblies on Si(111)-B. To do that,we have synthesis two organics molecules composed of an aromatic central part and two laterals chains (O-(CH2)9-CH3). The centralpart is composed of respectively three or five phenyl ring ended by cyano groups. We are also interested to the terminal groups effecton the network organisation. We show that the cyano groups effect on the "molecule/molecule" interaction and the "molecule/surface"interaction are negligible. Basis of the work conducted on the chapter four, we conclude our manuscript by presenting supramolecularsnetworks of dipolar molecule. These networks form dipole lines. We show that on small scale the molecules promote an alignment of theirdipolar moments

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36

Coury, Joseph Edward. "Scanning probe studies of small ligand-nucleic acid complexes." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/30501.

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Wittborn, Jesper. "Nanoscale studies of functional materials using scanning probe microscopy." Doctoral thesis, KTH, Materials Science and Engineering, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3000.

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This thesis deals with developing suitable modifications ofScanning Probe Microscopy (SPM) for investigations offunctional properties of materials. In order to make itpossible to investigate a number of properties of variousfunctional systemsusing SPM the following new techniques have beendeveloped:

A magnetic force microscope (MFM) having capability ofboth dc- and ac-mode detection.

A method to extract switching field distributions fromseries of MFM images.

A novel technique for magnetic microscopy using anon-magnetic probe to investigate the magnetostrictiveresponse of ferromagnetic materials, capable of 1 nmresolution.

A technique to determine the magnetostriction at lowexternal fields using AFM.

A technique for AFM studies of ferroelectric domainsusing the inverse piezoelectric effect of ferroelectricmaterials.

A technique for studying the relative stiffnessdistribution in composite materials using AFM.

Scanning friction microscopy.

Methods for determining the structure ofnanoindents.

Using the techniques highlighted above, we have studiedfunctional materials of current interest from bothtechnological and basic research points of view. Some of the materials and the main results obtainedare:

The role of magnetism arising from chains of nano-sizedmagnetite particles bio-mineralized in magneto-tacticbacteria is a topic of growing interest today. We use MFMtechniques to investigate magnetic flux reversal phenomena insuch chains. It is found that:

1.2.It is noteworthy that from our MFM measurements on singlemagnetosomes of 50 nm we havedetected magnetic moments as small as 3.1·10-14emu. Such detection is not possible by anyother technique known today.

1.2.

1.

2.

It is noteworthy that from our MFM measurements on singlemagnetosomes of 50 nm we havedetected magnetic moments as small as 3.1·10-14emu. Such detection is not possible by anyother technique known today.

Evaluation of magnetostrictive properties of smallstructures is extremely important and relevant to informationstorage media and read/write heads, in particular, as storagedensities beyond 30 gigabytes is pursued. In this thesis astudy of domain wall width of submicron man-made Co dots ispresented with a newly developed magnetostrictive imagingtechnique. Domain wall width of ~35 nm have been observed inmagnetic dots of 250 nm diameter. Additionally, we found thatdue to magnetostatic coupling the dots influence theneighboring domains to align ferromagnetically. The studiespresented herein are the first such to be reported inliterature.

From an investigation of epitaxially grown ferroelectricPbZr_0.65Ti_0.35O₃(PZT) thin films the existence of orderedpolydomain configurations in grains larger than 200 nm aredemonstrated.

For an understanding of the interaction between thecomponents of composite materials the relative stiffness wasdetermined for a composite material consisting of TiNinclusions in an Al₂O₃matrix. This would be a new approach to studythe local mechanical properties of future nano-compositematerials.

Preliminary investigations of the structure of nanoindentson a variety of materials demonstrate potentially richpossibilities to study the hardness at various depths inadvanced nanostructured materials

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Lei, Chunhong. "Nanoscale properties of conjugated polymers by scanning probe microscopy." Thesis, Cardiff University, 2004. http://orca.cf.ac.uk/55924/.

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Nanoscale properties of conjugated polymers by Scanning Probe Microscopy Atomic force microscopy (AFM) and electrostatic force microscopy (EFM) are explored and developed to study the surface potential distribution for a range of applications, including semiconductor laser devices, the electrical conductivity of aligned DNA molecules. The main focus of the thesis is the application of these techniques to investigate the nanoscale structures and electrical properties of conjugated polymers, including poly-(3-exylthiophene)s (P3ATs), polyfluorene (PFO), and poly-(3,4,-ethylenedioxythiophene) (PEDOT). EFM is a SPM technique, used to measure electrostatic force in non-contact mode. Two modes of EFM, scanning Kelvin probe microscopy (KPM or SKPM) and EFM/phase, are explored. Analytical calculations of tip-surface capacitances and their gradients are presented, aiming at quantifying the measurement. Based on the calculation results, the origin of the measurement resolution in EFM/phase and SKPM is explained, and a procedure is developed to convert the phase shift to the local surface potential. Thus, EFM/phase can also be used to measure the surface potential with higher resolution than SKPM. The self-assembled/aggregation structures of the polymers, as varied by molecular weight, solution preparation and substrates used, are investigated by AFM. The self-assembled structure, usually in the form of a network, obeys certain laws in its formation. The surface potential distributions and charge transport properties in polymer films and network structures are investigated with both EFM modes. The electrical properties of Au on poly-(3-hexylthiophene) (P3HT) and P3HT on Au contacts are investigated. The electrochemical reaction of conjugated polymers, and electropolymerisation of 3,4-ethylenedioxythiophene (EDOT) are carried out on micro electrodes, and studied by AFM. The EDOT electropolymerization is shown to grow polymer nano-wires or a uniform polymer film, depending on conditions the electropolymerization process.

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McKelvey, Kim Martin. "New approaches and applications in electrochemical scanning probe microscopy." Thesis, University of Warwick, 2012. http://wrap.warwick.ac.uk/56935/.

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This thesis is concerned with the development of new electrochemical scanning probe techniques and the application of these to biological problems. These techniques allow high resolution quantitative investigations of surface processes through measurements at a precisely placed electrode probe. A new technique, called intermittent contact scanning electrochemical microscopy, which allowed the probe-surface distance to be decisively determined through the physical interaction of the probe with the surface was developed. Separately, a new type of dual electrode probe was developed and characterised, and a new instrument (including both hardware and software) capable of a wide range of electrochemical imaging modes was developed with wide applications. The quantitative analysis of the electrochemical signal, typically measured at the probe, requires understanding the mass transport between the probe and the surface. Finite element modelling was used extensively throughout to solve the mass transport problem and therefore quantitatively analyse experimental results. Intermittent contact scanning electrochemical microscopy was used to quantify the mass transport through a porous biological membrane, dentin, that separates the pulp and enamel in teeth. Oxygen generation and consumption rates during photosynthesis were determined by measuring the local oxygen flux at an electrode placed a precise distance above a monolayer of isolated chloroplasts or thylakoid membranes. Finally, the new dual electrode probe was used to measure the reduction of an artificial electron acceptor by isolated thylakoid membranes.

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40

Harron, Hamish Robert. "The scanning probe microscopy study of thin polymer films." Thesis, De Montfort University, 1995. http://hdl.handle.net/2086/4167.

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41

Allen, Stephanie. "The study of biomolecular interactions using scanning probe microscopy." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363596.

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42

Jirlén, Johan. "Nanolithography with molecules using advanced scanning probe microscopy methods." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-68667.

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The possibilities of novel catalytic scanning probe lithography (cSPL) on starch using α-amylase was investigated. For this thin homogeneous layers of starch with good coverage were prepared by spin coating a starch solution on a silicon base. Amylase immobilized to an atomic force microscopy (AFM) cantilever tip were prepared and dragged along a spin coated starch surface. This after verifying the enzyme immobilization method using (3-Aminopropyl)triethoxysilane (APTES) on a silicon surface. In addition an unmodified cantilever tip were dipped in amylase solution and were dragged along a starch surface to investigate possibilities of dip-pen nanolithography (DPN). The preliminary experiments with AFM based enzymatic lithography were promising but non-conclusive. There are still many parameters not fully explored such as water availability, activity and reach of the amylase, speed of the enzymatic process and difference in structure between the starch and the shorter saccharides that are left after the hydrolysis

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43

Liu, Yangmingyue. "Scanning Electron Microscopy To Probe Working Nanowire Gas Sensors." OpenSIUC, 2013. https://opensiuc.lib.siu.edu/theses/1256.

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This study is dedicated to the implementing of Electron-Beam-Induced Current (EBIC) microscopy to study the behavior of metal oxide semiconducting (MOS) nanowire (NW) gas sensor in situ under exposure to different environment. First, we reported the development of a single nanowire gas sensor compatible with an environmental cell. The major component of the device we use in this study is a single SnO2 nanowire attached to an electron transparent SiN membrane (50-100 nm thick), which was used for mounting nanowire working electrodes and surface imaging of NW. First the NW's conductivity is investigated in different temperatures. Higher temperature is proved to cause higher conductivity of NW. We also found that often the Schottky barrier is formed at the nanowire's contacts with Au and Au/Cr electrodes. Then NW's responses to gas and electron beam (from SEM) are analyzed quantitatively by current measurement. Electron-Beam-Induced Current technique was introduced for the first time to characterize the conductivity behavior of the nanowire during the gas sensing process. Resistive contrast was observed in the EBIC image.

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Plumadore, Ryan. "Study of Two Dimensional Materials by Scanning Probe Microscopy." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/38637.

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This thesis explores structural and electronic properties of layered materials at the nanometre scale. Room temperature and low temperature ultrahigh vacuum scanning probe microscopy (scanning tunneling microscopy, scanning tunneling spectroscopy, atomic force microscopy) is used as the primary characterization method. The main findings in this thesis are: (a) observations of the atomic lattice and imaging local lattice defects of semiconducting ReS2 by scanning tunneling microscopy, (b) measurement of the electronic band gap of ReS2 by scanning tunneling spectroscopy, and (c) scanning tunneling microscopy study of 1T-TaS2 lattice and chemically functionalizing its defects with magnetic molecules.

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Kameni, Boumenou Christian. "Scanning probe force microscopy of III-V semiconductor structures." Thesis, Nelson Mandela University, 2017. http://hdl.handle.net/10948/13992.

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In this dissertation, cross-sectional potential imaging of GaAs-based homoepitaxial, heteroepitaxial and quantum well structures, all grown by atmospheric pressure Metal-organic Vapor Phase Epitaxy (MOVPE) is investigated. Kelvin probe force microscopy (KPFM), using amplitude modulation (AM) and frequency modulation (FM) modes in air and at room temperature, is used for the potential imaging. Studies performed on n-type GaAs homoepitaxial structures have shown two different potential profiles, related to the difference in electron density between the semi-insulating (SI) substrate and the epilayers. It is shown that the contact potential difference (CPD) between the tip and sample is higher on the semi-insulating substrate side than on the n-type epilayer side. This change in CPD across the interface has been explained by means of energy band diagrams indicating the relative Fermi level positions. In addition, it has also been found that the CPD across the interface increases with electron density. This result is in qualitative agreement with theory. In addition, as known from literature, even under ambient conditions FM mode KPFM provides better lateral resolution and more realistic CPD values than AM mode KPFM. Compared to the case of AM mode analysis, where the experimental CPD values were on average of the theoretical values, the CPD values from FM mode analysis are on average of the theoretical ones. Furthermore, by using FM mode, the transition across the interface is sharper and the surface potential flattens/saturates as expected when scanning sufficiently far away from the junction. The non-neutral space charge region of the sample with an electron density of for example, is as measured by FM-KPFM, whereas for AM-KPFM, the width is even more than and the potential profiles do not saturate. For the p-type GaAs homoepitaxial structures, FM mode measurements from a sample with a dopant density of are presented. As in the case of n-type GaAs,a similar potential profile showing two main domains has been obtained. However, unlike the case of type GaAs where the potential measured on the epilayer side is higher than that on the substrate side, the potential on the epilayer side of the junction is lower in this case due to the fact that the Fermi level of p-type GaAs is below that of the substrate.

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46

Stirling, Julian. "Scanning probe microscopy from the perspective of the sensor." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/14000/.

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The class of instruments considered in this thesis, scanning probe microscopes (SPM), raster scan a sensory probe over a surface to form both high resolution images and quantitative interaction measurements. Understanding and extracting information from SPM data has been considered extensively in the three decades since the first SPM. Major developments tend to be greeted with their own theory and data analysis techniques. The more gradual evolution of equipment has not, however, attracted the same level of theoretical consideration. In this thesis we consider the SPM from an instrumentation perspective, concentrating on two specific types of microscope: the scanning tunnelling microscope (STM) and the atomic force microscope (AFM). Both of these microscopes rely on a sensory probe or sensor to induce and measure the desired interaction. We have carefully considered a range of experiments from a `sensor-eye-view', both theoretically and experimentally. We first consider the effect of the geometry of AFM sensors on quantitative force measurements, identifying that the length of tips that the length of tips can induce an unwanted coupling of lateral and normal forces. We go further by developing methods to experimentally correct these force measurements along with designing a sensor which exploits symmetry to separate lateral and normal forces. We also consider the ways to automatically optimise the apex of the sensory probe of an STM to give the desired imaging resolution using a combination of prescribed routines and genetic algorithms. Image analysis techniques developed for this work have been developed into an open-source toolbox to automatically process and analyse SPM images. Finally, we use control theory to analyse the feedback controlling the SPM probe. We find that the methods used in the literature do not fully consider the method with which the control loop is implemented in SPM. We employ a modified approach which results in more realistic simulated SPM operation.

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47

Humphry, Martin James. "Novel scanning probe microscope instrumentation with applications in nanotechnology." Thesis, University of Nottingham, 2000. http://eprints.nottingham.ac.uk/13743/.

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A versatile scanning probe microscope controller has been constructed. Its suitability for the control of a range of different scanning probe microscope heads has been demonstrated. These include an ultra high vacuum scanning tunnelling microscope, with which atomic resolution images of Si surfaces was obtained, a custom-built atomic force microscope, and a custom-built photon emission scanning tunnelling microscope. The controller has been designed specifically to facilitate data acquisition during molecular manipulation experiments. Using the controller, the fullerene molecule C60 has been successfully manipulated on Si(100)-2x1 surfaces and detailed data has been acquired during the manipulation process. Evidence for two distinct modes of manipulation have been observed. A repulsive mode with success rates up to 90% was found to occur with tunnel gap impedances below 2GΩ, while between 2GΩ and 8GΩ attractive manipulation events were observed, with a maximum success rate of ~8%. It was also found that the step size between feedback updates had a significant effect on tip stability, and that dwell time of the STM tip at each data point had a critical effect on manipulation probability. A multi-function scanning probe microscope head has been developed capable of operation as a scanning tunnelling microscope and an atomic force microscope in vacuum and a magnetic field of 7T. The custom-built controller also presented here was used to control the head. A three-axis inertial sliding motor was developed for the head, capable of reproducible step sizes of <1000Å. In addition, an optical fibre interferometer was constructed with a sensitivity of 0.2Å/ √Hz. Preliminary development of a magnetic resonance force microscope mode has also been performed, with initial results showing such a system to be feasible.

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48

Wagner, Peter. "Scanning probe microscopy of biological macromolecules on Au(111) surfaces /." [S.l.] : [s.n.], 1995. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=11134.

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49

Oh, Jaehwan. "Electrical Characterization of TiSi2 Nanoscale Islands by Scanning Probe Microscopy." NCSU, 2001. http://www.lib.ncsu.edu/theses/available/etd-20010810-153432.

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AbstractOH, JAEHWAN. Electrical Characterization of TiSi2 Nanoscale Islands by ScanningProbe Microscopy. (Under the direction of Robert J. Nemanich)Using conducting tip atomic force microscopy (c-AFM), we have measured thecurrent voltage characteristics of individual sub-micron islands of TiSi2 on Si(100)surfaces and we have developed an imaging approach that distinguishes the electricalproperties of the islands. The Schottky barrier height (SBH) of the sub-micron TiSi2islands was deduced from the I-V measurements. The results indicate that there is asignificant variation of SBH among the islands on the same surface. The measurementsemploy a conventional AFM with a heavily B-doped diamond tip to obtain the currentvoltagerelations. In contact mode AFM, electrical signals are extracted independentlyfrom the topographic image. In addition, we have developed a new imaging method toprobe the local electrical properties of a surface with regions of different conductivity.Using a lock-in technique both phase and amplitude images were obtained, and theresultant image is essentially a map of the differential surface conductivity. Using thismethod, TiSi2 islands on a Si(100) surface were imaged. This approach can be readilyextended to other materials systems.Nanoscale TiSi2 islands of lateral diameter of ~5 nm are formed by electron beamdeposition of a few monolayers of titanium on atomically clean Si(111)7x7 surfacefollowed by in situ annealing at high temperatures (800-1000¡ÆC). Direct probing of theelectrical characteristics of these islands was performed using ultra high vacuumscanning tunneling microscope (UHV-STM) and scanning tunneling spectroscopy (STS).

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Wang, Li. "Spectroscopy and scanning probe microscopy studies of fullerene-silicon interaction." Thesis, University of Nottingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.416731.

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Dissertations / Theses on the topic 'Scanning probe microscopy. Nanoscience'

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