Dissertations / Theses: 'Scanning probe'

1

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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Mueller-Falcke, Clemens T. (Clemens Tobias). "Switchable stiffness scanning microscope probe." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32349.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.
Includes bibliographical references (p. 77-80).
Atomic Force Microscopy (AFM) has rapidly gained widespread utilization as an imaging device and micro/nano-manipulator during recent years. This thesis investigates the new concept of a dual stiffness scanning probe with respect to biological applications and determines the resulting requirements for the scanning of soft bio samples, such as low-pressure contact. On this basis, an in-plane AFM probe that is specifically tailored to the needs of biological applications is developed. It features a variable stiffness, which makes the stiffness of the probe adjustable to the surface hardness of the sample, and a very low overall stiffness, which is needed in order to achieve high resolution imaging. The switchable stiffness probe allows the scanning of biological samples with varying surface hardness without changing probes during scanning, and therefore prevents a loss of positional information, as is unavoidable with conventional devices. For the integration of the components into a MEMS device, the conventional cantilever-type design of AFM probes has been abandoned in favor of an in-plane design. The new design has an advantage in that it facilitates a high-density array of AFM probes and allows for easy surface micromachining of the integrated device. It also enables the future integration of micro-fluidic channels for reagent delivery and nanopipetting. For the scanning of nano-scale trenches and grooves, a multi-walled carbon nanotube, embedded in a nanopellet, is planned as a high-aspect-ratio tip. The variable stiffness is accomplished in a mechanical way by engaging or disengaging auxiliary beams to the compliant beam structure by means of electrostatically actuated clutches.
(cont.) For actuation, an electrostatic combdrive is considered to move the probe tip up and down. The vertical displacement of the tip can be measured by a capacitive sensor, which can easily be integrated into the system. A scaled-up proof-of-concept model is manufactured with surface-micromachining processes. The clutch performance is successfully tested and the dual stiffness concept is verified by measuring the stiffness of the device with the clutches engaged and disengaged.
by Clemens T. Mueller-Falcke.
S.M.

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Neubeck, Soeren. "Scanning probe investigations on graphene." Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/scanning-probe-investigations-on-graphene(e0838733-8f13-4221-ad55-124e3757ba15).html.

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In this thesis, scanning probe microscopy experiments on graphene and chemically modified graphene crystals are discussed. Since its discovery in 2004, graphene has not only impressed researchers and industry because it is a crystal that is only one atom thick, butalso because of its electronic transport properties. However, a major challenge remaining is the task to introduce an energy gap in graphene. One way to open an energy gap in pristine graphene is its confinement to nanometre sizes. To this end, methods were developed to fabricate such nanostructures out of graphene. Here, the atomic force microscope (AFM) based technique of local anodic oxidation was applied to selectively oxidise graphene. Using this technique, graphene nanostructures as small as 20~nm have been fabricated. A graphene quantum dot (QD) created with this technique was measured at low temperatures. It showed quantum Coulomb blockade behaviour, with an energy gap of 10 meV. Furthermore, the transport behaviour of these nanostructures was also investigated under ambient conditions.Scanning gate microscopy measurements carried out on a graphene quantum point contact (QPC) demonstrated the possibility to locally influence the charge carrier concentration in the QPC, and thus alter the resistance of the device. These experiments additionally prove the usefulness of local anodic oxidation to create graphene nanostructures. Equally tempting as opening a gap in graphene and studying the resulting transport properties is the prospect of studying the influence of the edges terminating a graphene crystal on its transport properties. To that end, reliable methods for obtaining the crystallographic orientation of a given edge are needed. While most techniques require either elaborated sample fabrication or modelling, it is shown here how atomically resolved scanning tunnelling microscopy (STM) imaging together with Raman spectroscopy can be used to determine the crystallographic direction of graphene edges without doubt. An alternative way of creating an energy gap in graphene is its modification with atomic hydrogen. Atomic force microscopy was first used to measure the topography of hydrogenated graphene crystals. It is further shown, how the amount of adsorbed hydrogen could be decreased using AFM. The changes induced in the hydrogenated graphene samples in this way have been further corroborated by Raman spectroscopy and low temperature transport experiments, establishing AFM as a method to engineer the resistance of hydrogenated graphene.

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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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7

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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Kossakovski, Dmitri A. Beauchamp Jesse L. Beauchamp Jesse L. "Scanning probe chemical and topographical microanalysis /." Diss., Pasadena, Calif. : California Institute of Technology, 2000. http://resolver.caltech.edu/CaltechETD:etd-02272009-085501.

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Stangoni, Maria Virginia. "Scanning probe techniques for dopant profile characterization /." [S.l.] : [s.n.], 2005. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=16024.

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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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Brunner, Andreas [Verfasser]. "Cryogenic NV Scanning Probe Magnetometry / Andreas Brunner." München : Verlag Dr. Hut, 2018. http://d-nb.info/1174426357/34.

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Watson, Scott M. D. "Scanning probe lithography of chemically functionalised surfaces." Thesis, Durham University, 2008. http://etheses.dur.ac.uk/2055/.

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A facile route to the production of highly uniform, ultra-thin metal oxide films has-been demonstrated using a combination of self-assembly and Langmuir-Blodgett techniques. Initial modification of a Si/SiO(_2) substrate through self-assembly of an octadecylsiloxane monolayer provides a hydrophobic surface suitable for the "tail down" deposition of a Langmuir-Blodgett monolayer of octadecylphosphonic acid, giving. The resulting –PO(_3)H(_2) functionalised film provides a suitable surface for binding of metal ions (e.g. Zr(^4+), Hf(^4+), Mg(^2+)). The tendency of these metal species to form polymeric structures in aqueous solution allows for the assembly of nanometre thick inorganic metal layers upon the –PO(_3)H(_2) surface. Thermal treatment of the Langmuir-Blodgett films was used to decompose the organic film components, whilst simultaneously calcining the inorganic metal layer, resulting in the formation of highly uniform metal oxide films, typically ca. 1.3 - 1.9 nm thick. Nanoscale patterning of the metal-stabilised Langmuir-Blodgett monolayers has also been demonstrated, by using an AFM probe to apply sufficiently high vertical forces upon the Langmuir-Blodgett surface to selectively displace the monolayer film material within spatially defined surface regions. Pattern resolutions dowm to 30 nm were achieved using this AFM "nanodisplacement" lithographic process. Excellent levels of structural retention of the patterns were also observed upon decomposition of the organic film components to generate the final metal oxide. Similarly, nanodisplacement patterning of metal-stabilised Langmuir-Blodgett monolayers deposited upon amino-flinctionalised substrates has been used for the fabrication of amine patterned surfaces. Selective binding of Au nanoparticles within the amine regions was demonstrated, highlighting the potential of such patterned surfaces as chemical templates for directing the assembly and organisation of other materials

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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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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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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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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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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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Lu, Xi. "Advanced scanning probe lithography and its parallelization." Diss., Georgia Institute of Technology, 2016. http://hdl.handle.net/1853/54943.

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Nanofabrication is the process of making functional structures with arbitrary patterns having nanoscale dimensions. Nanofabrication has been widely implemented in industry for improving microelectronic devices and data storage technology, to increase the component density, to lower the cost and to increase the performance. Other areas of applications include optics, cell biology and biomedicine. One of the most critical challenges in the development of next generation nanoscale devices is the rapid, parallel, precise and robust fabrication of nanostructures. In this thesis work, we demonstrate the possibility to parallelize the thermochemical nanolithography (TCNL) by creating nanoscale patterns with a tip array, containing five identical thermal cantilevers. The versatility of our technique is demonstrated by creating nanopatterns simultaneously on multiple surfaces, including graphene oxide and conjugated polymers. This work also involves the study of the reduction process of graphene fluoride through TCNL and the study of the local anodic oxidation of epitaxial graphene, to create high quality graphene nanoribbons.

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Doughty, Jeffrey Jon. "Symmetric Near-Field Probe Design and Comparison to Asymmetric Probes." PDXScholar, 2010. https://pdxscholar.library.pdx.edu/open_access_etds/390.

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Tip Enhanced Near-field Optical Microscopy (TENOM) is a method for optically imaging at resolutions far below the diffraction limit. This technique requires optical nano-probes with very specialized geometries, in order to obtain large, localized enhancements of the electromagnetic field, which is the driver behind this imaging method. Traditional methods for the fabrication of these nano-probes involve electrochemical etching and subsequent FIB milling. However, this milling process is non-trivial, requiring multiple cuts on each probe. This requires multiple rotations of the probe within the FIB system, which may not be possible in all systems, meaning the sample must be removed from vacuum, rotated by hand and placed back under vacuum. This is time consuming and costly and presents a problem with reproducibility. The method presented here is to replace multiple cuts from a side profile with a small number of cuts from a top down profile. This method uses the inherent imaging characteristics of the FIB, by assigning beam dwell times to specific locations on the sample, through the use of bitmap images. These bitmaps are placed over the sample while imaging and provide a lookup table for the beam while milling. These images are grayscale with the color of each pixel representing the dwell time at that pixel. This technique, combined with grayscale gradients, can provide probes with a symmetric geometry, making the system polarization independent.

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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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Eichenberger, Nicolas. "Scanning probe investigations at stepped and heterogeneous electrodes /." [S.l.] : [s.n.], 2004. http://www.zb.unibe.ch/download/eldiss/04eichenberger_n.pdf.

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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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Vega, González Myraida Angélica. "Dynamic study of tunable stiffness scanning microscope probe." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32967.

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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.
Includes bibliographical references (leaf 31).
This study examines the dynamic characteristics of the in-plane tunable stiffness scanning microscope probe for an atomic force microscope (AFM). The analysis was carried out using finite element analysis (FEA) methods for the micro scale device and its macro scale counterpart, which was designed specifically for this study. Experimental system identification testing using sound wave and high-speed camera recordings was clone on the macro scale version to identify trends that were then verified in the micro scale predictions. The results for the micro scale device followed the trends predicted by the macro scale experimental data. The natural frequencies of the device corresponded to the three normal directions of motion, in ascending order from the vertical direction, the out-of- plane direction, and the horizontal direction. The numerical values for these frequencies in the micro scale are 81.314 kHz, 51.438 kHz, and 54.899 kHz for the X, Y, and Z directions of vibration respectively. The error associated with these measurements is 6.6% and is attributed to the high tolerance necessary for measurements in the micro scale, which was not matched by the macro scale data acquisition methods that predict the natural frequency range.
(cont.) The vertical vibrations are therefore the limiting factor in the scanning speed of the probe across a sample surface, thus requiring the AFM to scan at an effective frequency of less than 81.3 kHz to avoid resonance.
by Myraida Angélica Vega González.
S.B.

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Chen, Rongrong. "Applications of scanning probe microscopies in electrocatalytic systems." Case Western Reserve University School of Graduate Studies / OhioLINK, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=case1057072469.

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Ott, Michael. "Quantitative capacitance measurements using a scanning probe microscope." Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27280.

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This thesis describes the theory, simulation and experimental implementation of a method by which an atomic force microscope with scanning capacitance microscopy (SCM) capability can be employed in a nontraditional fashion to quantitatively measure the capacitance of metal-oxide-semiconductor (MOS) structures. The capability to deduce sample capacitances is based on resonant frequency shifting, which relies on the SCM's ultra-precise capacitance sensor. The technique, however, is distinct from scanning capacitance microscopy imaging, with the MOS capacitor an integral part of the system resonant circuit. SPICE simulations are performed to extract phenomenological resonant circuit parameters specific to the instrumentation, subsequently permitting sample capacitance to be quantitatively extracted from the system response. Our technique represents a novel application of SCM instrumentation and has important applications in the analysis of on-chip passive components for future technology generations. Initial experimental results are promising, suggesting the extension of the technique to advanced technology nodes.

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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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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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Dubosson, Fabrice. "Optical coherence tomography : 3-D dental scanning imaging probe /." Sion, 2007. http://doc.rero.ch/search.py?recid=8351&ln=fr.

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Zhou, Xiaotian. "Scanning probe characterization of novel semiconductor materials and devices." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2007. http://wwwlib.umi.com/cr/ucsd/fullcit?p3244779.

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Thesis (Ph. D.)--University of California, San Diego, 2007.
Title from first page of PDF file (viewed February 23, 2007). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.

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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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Li, Jingxin. "A scanning probe study of self-assembled alkylsilane films." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ63325.pdf.

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Ruskell, Todd Gary 1969. "Semiconductor modification and characterization with a scanning probe microscope." Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/282152.

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The capabilities of a commercially available atomic force microscope system have been expanded to include sub-picoampere measurements of local surface conductivity. This multiple mode analysis tool is capable of providing local I/V curves, current maps at a constant voltage, or voltage maps at a constant current, simultaneously with the usual topographic data obtained for a given sample. The resulting electrical maps and local I/V curves from several samples are presented, and their interpretation discussed. Additionally, this system has been used for field-induced silicon oxide growth and, for the first time, silicon nitride growth. The mechanism for both SiO2 and Si3 growth is explored, revealing the possibility of precisely controlling the uniformity of the lithographed features.

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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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Yim, C. M. "Scanning probe and spectroscopy studies of rutile TiO2(110)." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1344103/.

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In this thesis, surface science techniques were employed to study the chemistry of rutile TiO2(110). Scanning tunnelling microscopy (STM) and ultraviolet photoemission spectroscopy (UPS) have been used to determine the origin of the band-gap state in rutile TiO2(110). By employing electron bombardment to vary the Ob-vac density while monitoring the band-gap state with UPS, we demonstrate that Ob-vac make dominant contribution to the photoemission peak and that is magnitude is directly proportional to the Ob-vac density. CO adsorption on the Pd/TiO2(110) surface was investigated with synchrotron radiation spectroscopies and STM. The Pd islands, which were grown by physical vapour deposition (PVD) of Pd onto the TiO2(110) substrate at ~800 K, had a pseudo-hexagonal shape and were not encapsulated with Ti^n+ (n<4) species from the substrate. In addition, it was found that CO molecules bond vertically and form various ordered overlayers on the Pd(111) islands. O2 adsorption on the cross-linked TiO2(110)-(1x2) surface was investigated with XPS, UPS and STM. The introduction of a small amount of O2 leads to a drastic reduction in the number of the Ti3+ species at the topmost surface layers and the band-gap state intensity, as well as a noticeable rise in the surface workfunction. In STM, O2 and its related molecules were found to preferably adsorb at the centre of the (1x2) strands. Current imaging tunnelling spectroscopy (CITS) was also performed on the same surface at 78 K. It was found that the densities of the two occupied states, one at -0.7 V and and another at -1.3 V, vary between different features on the surface. Moreover, whilst having less-populated occupied states, the cross-links possess an empty state at 1.2 V which cannot be detected anywhere else. This work will be compared with theoretical calculations to elucidate the geometric structure of the cross-link TiO2(110)-(1x2) surface.

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Dissertations / Theses on the topic 'Scanning probe'

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