Academic literature on the topic 'Nc-AFM'
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Journal articles on the topic "Nc-AFM"
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OHNISHI, Hiroshi. "NC-AFM 2000." Hyomen Kagaku 22, no. 3 (2001): 210. http://dx.doi.org/10.1380/jsssj.22.210.
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Laflör, Linda, Michael Reichling, and Philipp Rahe. "Protruding hydrogen atoms as markers for the molecular orientation of a metallocene." Beilstein Journal of Nanotechnology 11 (September 22, 2020): 1432–38. http://dx.doi.org/10.3762/bjnano.11.127.
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A distinct dumbbell shape is observed as the dominant contrast feature in the experimental data when imaging 1,1’-ferrocene dicarboxylic acid (FDCA) molecules on bulk and thin film CaF2(111) surfaces with non-contact atomic force microscopy (NC-AFM). We use NC-AFM image calculations with the probe particle model to interpret this distinct shape by repulsive interactions between the NC-AFM tip and the top hydrogen atoms of the cyclopentadienyl (Cp) rings. Simulated NC-AFM images show an excellent agreement with experimental constant-height NC-AFM data of FDCA molecules at several tip–sample distances. By measuring this distinct dumbbell shape together with the molecular orientation, a strategy is proposed to determine the conformation of the ferrocene moiety, herein on CaF2(111) surfaces, by using the protruding hydrogen atoms as markers.
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Hosaka, Sumio, Takayuki Takizawa, Daisuke Terauchi, You Yin, and Hayato Sone. "Pico-Newton Controlled Step-in Mode NC-AFM Using a Quadrature Frequency Demodulator and a Slim Probe in Air for CD-AFM." Key Engineering Materials 497 (December 2011): 95–100. http://dx.doi.org/10.4028/www.scientific.net/kem.497.95.
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We have studied a step-in mode non-contact atomic force microscopy (NC-AFM) for precise measurement of fine and steep structure with nanometer resolution in air. When a high aspect structure is measured using step-in mode AFM with the sharpened and slim probe, it is required that AFM control has to be performed at a force of <1 nN in pico-Newton range to suppress the bending and slipping of the probe on slop. Using a home-made step-in mode NC-AFM using a quadrature frequency demodulator for resonant frequency shift of the cantilever, the NC-AFM demonstrated that Si steep structure was faithfully observed at about 2 pN in air.
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Katsube, Daiki, Ryota Shimizu, Yoshiaki Sugimoto, Taro Hitosugi, and Masayuki Abe. "Identification of OH groups on SrTiO3(100)-( 13×13)-R33.7° reconstructed surface by non-contact atomic force microscopy and scanning tunneling microscopy." Applied Physics Letters 122, no. 7 (February 13, 2023): 071602. http://dx.doi.org/10.1063/5.0139493.
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Atomic resolution imaging of a SrTiO3(100)-([Formula: see text])-R33.7° reconstructed surface using non-contact atomic force microscopy (NC-AFM) and its simultaneous measurement with scanning tunneling microscopy (STM) is presented. Simultaneous STM and NC-AFM imaging reveals three patterns of image contrast depending on the tip apex condition and the relationship between the SrTiO3(100)-([Formula: see text])-R33.7° surface reconstructed structure and the NC-AFM image contrast. The NC-AFM image contrast variation is deduced from the tip apex polarity on the basis of an analysis of two images with opposite contrast. This interpretation is consistent with the results of simultaneous imaging of the SrTiO3(100)-([Formula: see text])-R33.7° surface. Furthermore, the results and interpretation identified an OH group, which is one of the surface defects, and this adsorption site.
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Lübbe, Jannis, Matthias Temmen, Philipp Rahe, and Michael Reichling. "Noise in NC-AFM measurements with significant tip–sample interaction." Beilstein Journal of Nanotechnology 7 (December 1, 2016): 1885–904. http://dx.doi.org/10.3762/bjnano.7.181.
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The frequency shift noise in non-contact atomic force microscopy (NC-AFM) imaging and spectroscopy consists of thermal noise and detection system noise with an additional contribution from amplitude noise if there are significant tip–sample interactions. The total noise power spectral density D Δ f (f m) is, however, not just the sum of these noise contributions. Instead its magnitude and spectral characteristics are determined by the strongly non-linear tip–sample interaction, by the coupling between the amplitude and tip–sample distance control loops of the NC-AFM system as well as by the characteristics of the phase locked loop (PLL) detector used for frequency demodulation. Here, we measure D Δ f (f m) for various NC-AFM parameter settings representing realistic measurement conditions and compare experimental data to simulations based on a model of the NC-AFM system that includes the tip–sample interaction. The good agreement between predicted and measured noise spectra confirms that the model covers the relevant noise contributions and interactions. Results yield a general understanding of noise generation and propagation in the NC-AFM and provide a quantitative prediction of noise for given experimental parameters. We derive strategies for noise-optimised imaging and spectroscopy and outline a full optimisation procedure for the instrumentation and control loops.
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Foster, A. S., A. L. Shluger, and R. M. Nieminen. "Realistic model tips in simulations of nc-AFM." Nanotechnology 15, no. 2 (January 13, 2004): S60—S64. http://dx.doi.org/10.1088/0957-4484/15/2/013.
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LeDue, J. M., M. Lopez-Ayon, S. A. Burke, Y. Miyahara, and P. Grütter. "HighQoptical fiber tips for NC-AFM in liquid." Nanotechnology 20, no. 26 (June 10, 2009): 264018. http://dx.doi.org/10.1088/0957-4484/20/26/264018.
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Bennewitz, R., O. Pfeiffer, S. Schär, V. Barwich, E. Meyer, and L. N. Kantorovich. "Atomic corrugation in nc-AFM of alkali halides." Applied Surface Science 188, no. 3-4 (March 2002): 232–37. http://dx.doi.org/10.1016/s0169-4332(01)00910-2.
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Hölscher, H., W. Allers, U. D. Schwarz, A. Schwarz, and R. Wiesendanger. "Simulation of NC-AFM images of xenon(111)." Applied Physics A 72, S1 (March 2001): S35—S38. http://dx.doi.org/10.1007/s003390100724.
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Katsube, Daiki, Hayato Yamashita, Satoshi Abo, and Masayuki Abe. "Combined pulsed laser deposition and non-contact atomic force microscopy system for studies of insulator metal oxide thin films." Beilstein Journal of Nanotechnology 9 (February 21, 2018): 686–92. http://dx.doi.org/10.3762/bjnano.9.63.
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We have designed and developed a combined system of pulsed laser deposition (PLD) and non-contact atomic force microscopy (NC-AFM) for observations of insulator metal oxide surfaces. With this system, the long-period iterations of sputtering and annealing used in conventional methods for preparing a metal oxide film surface are not required. The performance of the combined system is demonstrated for the preparation and high-resolution NC-AFM imaging of atomically flat thin films of anatase TiO2(001) and LaAlO3(100).
Dissertations / Theses on the topic "Nc-AFM"
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Bamidele, Joseph. "Theoretical modelling and characterisation of concerted tip and surface effects in NC-AFM." Thesis, King's College London (University of London), 2013. https://kclpure.kcl.ac.uk/portal/en/theses/theoretical-modelling-and-characterisation-of-concerted-tip-and-surface-effects-in-ncafm(e3fb52bf-5ff8-46e2-a0f7-e9a1fcb688b9).html.
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Rising interest in functionalising molecules and surface and building nano-devices, that is nanotechnology, has influenced demand for techniques that image molecules and surfaces with atomic precision. One such technique that has answered this call is Non-Contact Atomic Force Microscopy (NC-AFM), which has a very successful history of directly probing many atomic properties on a wide variety of systems. Interpretation of measurements, however, is highly dependent on knowledge of the atomic probe tip, which is generally elusive and is the most problematic issue surrounding the field. Another such issue is in understanding the atomic processes behind measurements, which to a large extent, also depends on knowledge of the atomic tip termination. Since its development, theorists have been attempting to fill in this knowledge gap, making signicant progress, but a substantial gap still remains. This thesis therefore addresses these two issues from a theoretical viewpoint. After describing the theoretical model used to simulate NC-AFM behaviour, it is used in conjunction with various theoretical techniques to study three important effects on NC-AFM measurements contributing to these issues: different tip terminations, chemical and structural; the relative stabilities of the surfaces and instabilities within the surface; surfaces defects. The systems studied were the p(2 1) and c(6 1) reconstructions of the oxidised copper (110) surface and the buckled dimer c(4 2) reconstruction of the silicon (001) surface. The stabilities of the two Cu(110):O surfaces were studied thermodynamically, where conventional theoretical methods were found to unexpectedly fail to accurately describe them, and corrections for this were studied. Using this knowledge, NC-AFM simulations were performed using two different chemical tip terminations, and were compared to experimental results, where tip identification was found to be possible on the c(6 1) surface and the p(2 1) surface if a common ad-atom defect is present. Instabilities in the third surface were studied using two different structural tip terminations, where dissipation signals were found to probe the tip-surface interactions in a specic way, due predominantly to soft modes in the surface. The role of defects in NC-AFM manipulations of this surface were then studied, which was found to be crucial to successful manipulation of the surface. As a result of these studies, a tip identification protocol whose successful implementation is novel as well as a novel atomic switching manipulation protocol have been demonstrated. This research demonstrates the important role of theory in addressing some of the most problematic issues limiting unambiguous interpretation of NC-AFM measurements. The studies have elucidated the atomic processes behind atomic NC-AFM dissipation signals when probing a surface with soft modes and have increased our ability to characterise different atomic tips.
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Turek, Natalia. "Imagerie à haute résolution des assemblages moléculaires par nc-AFM et KPFM à basse température." Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1I106.
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Le progrès important de la microscopie à force atomique sans contact (nc-AFM) au cours de la dernière décennie a permis d'étudier les propriétés structurelles et électroniques des molécules à l'échelle sub-moléculaire. Le processus de fonctionnalisation de la pointe, qui consiste à attacher des atomes ou des molécules uniques à l'apex de la pointe, a démontré une résolution exaltée des images STM et AFM, de sorte que les structures chimiques de nombreuses molécules différentes déposées sur des surfaces métalliques ont été résolues. Cependant, peu d'études ont été présentées jusqu'à présent sur des surfaces de semiconducteurs. Dans cette thèse, nous étudions la formation d'auto-assemblages moléculaires sur la surface passivée du silicium Si(111)-(√3x√3)R30°-B dopée au bore par STM/nc-AFM combiné avec Kelvin Probe Force Microscopy (KPFM). Les expériences ont été réalisées sur un microscope AFM/STM Joule-Thomson (SPECS), travaillant sous ultra-vide à une température de 4 K, en utilisant un capteur de force à haute rigidité (Kolibri, k=540 kN/m, f0=1 MHz). Les molécules étudiées sont : 1-(4'cyanophényl)-2,5-bis(décyloxy)-2,5-bis(décyloxy)-4-(4'-iodophényl)benzène (CDB-I), qui possèdent deux chaînes aliphatiques fixées à un noyau triphényle avec deux terminaisons différentes (soit iode, soit cyano) et la molécule nonpolaire 1,4 bis(4'cyanophényle)-2,5bis(décyloxy)benzène (CDB), avec deux terminaisons cyano identiques. Le premier objectif principal de ce travail était de vérifier la sensibilité de la sonde Kolibri dans la détection de charge. Les mesures KPFM portent sur les défauts du substrat dopé au bore, montrant les différents états de charge pour la liaison pendante (DB), la lacune de silicium et le dopant de bore enterré. L'état de charge positif est trouvé pour la DB, conformément aux études antérieures de la STM. Le potentiel de surface du défaut constitue la valeur de référence d'une seule charge sur la surface. Le deuxième objectif de cette thèse était d'obtenir une résolution sub-moléculaire en topographie et en imagerie KPFM sur les molécules, sans fonctionnalisation intentionnelle de la pointe. Un contraste sub-moléculaire est observé dans les images de décalage de fréquence de molécules individuelles, permettant l’identification du noyau triphényle et des détails des chaînes aliphatiques. De plus, la haute résolution est également obtenue dans les images de potentiel de surface des mesures KPFM. Selon le type d'adsorption de la molécule en surface, on distingue deux contrastes KPFM différents. Enfin, la comparaison de l'organisation dans les assemblages est faite pour les molécules CDB et CDB-I. Malgré l'organisation similaire des deux molécules dans les images nc-AFM, une différence de potentiel de surface est observée pour les deux terminaisons de la molécule CDB-I, indiquant l'organisation dipolaire le long des rangées de molécules des auto-assemblagesThe progress of non-contact Atomic Force Microscopy (nc-AFM) in the last decade enabled studying the structural and electronic properties of molecules at the submolecular scale. The process of tip functionalization relying in attaching single atoms or molecules to the tip apex demonstrated an enhanced resolution in both STM and AFM images, such that the chemical structures of many different molecules deposited on metallic surfaces have been resolved. However, few studies have been presented on a semiconductor surface so far. In this work, we study the formation of molecular self-assemblies on the passivated surface of boron doped silicon Si(111)-(√3x√3)R30°-B by combined STM/nc-AFM with Kelvin Probe Force Microscopy (KPFM). The experiments have been performed on the Joule-Thomson Scanning Probe Microscope (SPECS), working in ultra high vacuum at temperature of 4 K, using a high stiffness sensor (Kolibri, k=540 kN/m, f0=1 MHz). The investigated molecules are: 1-(4’cyanophenyl)-2,5-bis(decyloxy)-4-(4’-iodophenyl)benzene (CDB-I), which possess two aliphatic chains attached to a triphenyl core ended with two different terminations (either iodine or cyano group) and non-polar 1,4 bis(4'cyanophenyl)-2,5bis(decyloxy)benzene (CDB) molecule, with two identical cyano group terminations. The first main objective of this work was to verify the sensitivity of the Kolibri sensor in the charge detection. KPFM measurements of boron doped silicon defects are presented, showing different charge states for dangling bond (DB), silicon vacancy and buried boron dopant defects. A positive charge state is found for the DB, in accordance with previous STM studies. The surface potential of this defect constitutes a reference value of a single charge on the surface. The second objective of this thesis was to obtain submolecular resolution in topography and electrical imaging on molecules, without intentional tip functionalization. A submolecular contrast is observed in the frequency shift images of single molecules with identification of the three-phenyl core and details of the aliphatic chains. Moreover, a high resolution is obtained in the surface potential images from KPFM measurements as well. Depending on type of the adsorption of molecule on the surface, two different KPFM contrasts are distinguished. Lastly, the comparison of organization in the assemblies is done for both CDB and CDB-I molecules. A similar organization is found for both molecules in nc-AFM images. The asymmetry of the nc-AFM topography and KPFM map of CDB-I molecules indicates the dipolar organization along a given assembly row
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Burke, Sarah A. "Buckminsterfullerene on KBr studied by high resolution NC-AFM : molecular nucleation and growth on an insulator." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81605.
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Non-contact atomic force microscopy (NC-AFM) has been applied to the prototypical molecule-insulator system C60 on KBr. Both contact and non-contact imaging modes were used to characterize the KBr(001) surface. C60 molecules were deposited on UHV-cleaved KBr(001) surfaces and imaged with NC-AFM. Surveys of the surface revealed an island growth mode with a tendency towards nucleation at step edges. A long diffusion length was also estimated (600-800nm) from survey images. Molecular resolution images were also obtained revealing a coincident epitaxy between the C60 molecules and the substrate. Also, a 20 +/- 3pm height difference is observed between some first layer molecules, closely corresponding to the geometrical height difference between two orientations of C60. Nucleation of C60 at kink sites was directly observed by NC-AFM and a calculation of the electrostatic forces on a C60 molecule at a kink in a KBr step confirms an additional contribution to the substrate-adsorbate interaction.
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Ardhuin, Thibault. "Étude par STM et NC-AFM des mécanismes de charge de molécules individuelles sur substrats isolants." Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30315.
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Ces dernières années sont apparues de nouvelles techniques permettant le contrôle de la charge de nano-objets individuels (atome, molécule, agrégat métallique ou semi-conducteur, ...) déposés sur substrats isolants. Cet aboutissement a été rendu possible par le perfectionnement des méthodes de microscopie à effet tunnel (STM) et à force atomique (AFM). En combinant ces outils, les précurseurs ont réussi à maîtriser l'état de charge d'un atome d'or déposé sur une bicouche de NaCl(001) sur substrat Cu(111). Par la suite, ce type de manipulation a été étendu à des systèmes moléculaires notamment au CEMES avec Cu(dbm)2. Ce sujet s'inscrit dans la continuité de ces études. L'objectif était d'analyser l'impact de l'augmentation de l'épaisseur du film isolant sur les mécanismes de charge. Cette problématique requière une quantification de l'état de charge du système ainsi qu'une mesure de l'épaisseur d'isolant. Dans ce travail, nous avons pu étudier des films de KBr et NaCl déposés sur des surfaces de Cu(111) et Ag(111). Pour ces études, que ce soit en courant tunnel (STM) ou en gradient de force (NC-AFM), le contrôle de l'état de pointe est essentiel. Lorsque l'on travaille sur substrat isolant, la pointe a tendance à collecter des contaminants qui en changent les propriétés électroniques. Or, pour charger un système de manière reproductible, il nous faut impérativement contrôler la métallicité de l'apex. Cette maîtrise passe par une re-préparation fréquente de la pointe sur une surface métallique, difficile à trouver dans le cas d'un film épais. Pour pallier à cette rareté, nous avons mis en place un masque de dépôt permettant un contrôle du gradient de l'épaisseur du film isolant tout en préservant des zones de métal libre. Cela nous a permis de réaliser nos mesures avec un état de pointe mieux contrôlé. L'instabilité de l'état de pointe nous a également conduit à effectuer des spectroscopies à courant régulé de type Z(V). En contrôlant ce courant, il est alors possible de minimiser l'interaction entre la pointe et le film isolant, préservant ainsi plus longtemps la pointe. Ces spectroscopies Z(V) permettent également d'augmenter la tension de mesure jusqu'à atteindre le régime d'émission de champ. Nous avons observé par cette méthode une variation de la modulation de l'amplitude des résonances d'émission de champ (FER) en fonction de l'épaisseur du film isolant. Une modélisation numérique par différences finies a été développée afin de comprendre ce phénomène. [..]In recent years, new techniques have emerged to control the charge of individual nano-objects (atom, molecule, metal aggregate or semiconductor, etc.) deposited on insulating substrates. This achievement has been made possible by the refinement of Tunneling Microscopy (STM) and Atomic Force (AFM) methods. By combining these tools, the precursors succeeded in controlling the state of charge of a gold atom deposited on a NaCl (001) bilayer on a Cu (111) substrate. Subsequently, this type of manipulation has been extended to molecular systems, in particular at the CEMES with Cu(dbm)2. This subject is part of the continuity of these studies. The objective was to analyze the impact of the increase of the thickness of the insulating film on the charge mechanisms. This problem requires a quantification of the state of the system charge as well as a measurement of the insulation thickness. In this work, we have been able to study KBr and NaCl films deposited on Cu(111) and Ag(111) surfaces. For these studies, whether in tunnel current (STM) or force gradient (NC-AFM), the control of the tip state is essential. When working on an insulating substrate, the tip tends to collect contaminants that change their electronic properties. However, to charge a system in a reproducible way, we must imperatively control the metallicity of the apex. This control requires a frequent re-preparation of the tip on a metal surface, difficult to find in the case of a thick film. To overcome this scarcity, we have implemented a deposition mask allowing a control of the gradient of the thickness of the insulating film while preserving clean metal zones. This allowed us to carry out our measurements with a better controlled state of the tip. The instability of the tip state has also led us to perform Z (V) regulated current spectroscopies. By controlling this current, it is then possible to minimize the interaction between the tip and the insulating film, thus making the tip last longer. These Z (V) spectroscopies also make it possible to increase the measurement voltage until reaching the field emission regime. We have observed a variation of the modulation of the field emission resonances (FER) amplitude as a function of the thickness of the insulating film. [...]
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Mandia, David J. "NC-AFM and XPS Investigation of Single-crystal Surfaces Supporting Cobalt (III) Oxide Nanostructures Grown by a Photochemical Method." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23117.
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The work of this thesis comprises extensive Noncontact Atomic Force Microscopy (NC-AFM) characterization of clean metal-oxide (YSZ(100)/(111) and MgO(100)) and graphitic (HOPG) supports as templates for the novel, photochemically induced nucleation of cobalt oxide nanostructures, particularly Cobalt (III) Oxide. The nanostructure-support surfaces were also studied by X-ray Photoelectron Spectroscopy (XPS) to verify the nature of the supported cobalt oxide and to corroborate the surface topographic and phase NC-AFM data. Heteroepitaxial growth of Co2O3 nanostructures proves to exhibit a variety of different growth modes based on the structure of the support surface. On this basis, single-crystal support surfaces ranging from nonpolar to polar and atomically flat to highly defective and reactive were chosen, again, yielding numerous substrate-nanostructure interactions that could be probed by high-performance surface science techniques.
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Tchalala, Mohamed Rachid. "Croissance et réactivité du silicène." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112287/document.
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L’objet de cette thèse est l’étude de la croissance de silicène sur des substrats d’argent,ainsi que l’étude de sa réactivité vis-à-vis de l’oxygène. La croissance a été réalisée sous ultra-vide et contrôlée par spectroscopie d’électrons Auger (AES) et par diffraction d’électrons lents (LEED). Les structures obtenues et leurs réactivités à l’oxygène ont été étudiées par microscopie à champ proche (STM et nc-AFM) et par spectroscopie de photoémission résolue en angle (ARPES). Nous avons étudié la structure interne des nano-rubans de silicène auto-assemblés sur un substrat d’Ag(110). Sur Ag(111) nous obtenons un feuillet de silicène qui présente différentes structures en fonction de la température du substrat. L’étude de la réactivité des rubans et des feuillets a montré que le silicène formé sur substrat d’argent est relativement stable vis-à-vis de l’oxygène ce qui ouvre des perspectives de fonctionnalisation du silicène. La dernière partie de cette thèse concerne la synthèse de feuillets de silicium par voie chimique. Nous avons mis au point une nouvelle méthode prometteuse de synthèse chimique qui nous a permis de synthétiser des feuillets de silicium de structure graphitiqueThe objective of this thesis is the study of the growth of silicene on silver substrates as well as its reactivity towards the oxygen. The growth was performed under ultra-high vacuum and controlled by Auger electrons spectroscopy (AES) and low energy electrons diffraction (LEED). The obtained structures and their relativities towards the oxygen were studied by near field microscopy (STM and nc-AFM) and by angle resolved electrons photoemission spectroscopy (ARPES). We have studied the internal structure of the selfassembled silicene nanoribbons on Ag(110) substrate. On Ag(111), we have obtained a silicene sheet presenting different structures versus the temperature of the substrate. The reactivity of silicene nanoribbons and sheets grown on silver show that silicene is relatively stable towards the oxygen which opens a new perspectives of functionalization of the silicene. The last part of this thesis concerns the synthesis of silicone sheets by chemical process. We have develpped a new promising process of chemical synthesis which allowed us to synthesize silicon sheets with graphitic structure
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Spadafora, Evan. "Etude par microscopie à force atomique en mode non contact et microscopie à sonde de Kelvin, de matériaux modèles pour le photovoltaïque organique." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00647312.
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La nanostructure et les propriétés électroniques de matériaux modèles pour le photovoltaïque organique, ont été étudiées en utilisant la Microscopie à Force Atomique en mode non contact sous ultra-vide (NC-AFM) et la Microscopie à sonde de Kelvin (KPFM). En utilisant le mode modulation d'amplitude (AM-KPFM), le potentiel de surface photo- généré dans des mélanges donneur-accepteur présentant une ségrégation de phase optimale a pu être visualisé à l'échelle du nanomètre. Afin de préciser la nature des forces mises en jeu dans le processus d'imagerie KPFM, des oligomères π-conjugués auto-assemblés ont ensuite été étudiés. Une transition entre régimes à longue et à courte portée a ainsi été mise en évidence en combinant l'imagerie en haute résolution aux mesures de spectroscopie en distance. Ces mesures ont également démontré que l'influence des forces électrostatiques à courte portée peut être minimisée en travaillant au seuil du contraste de dissipation. Enfin cette procédure a été utilisée, en combinaison avec les mesures de spectroscopie de photoélectrons UV, pour analyser la fonction de sortie locale d'électrodes transparentes à base de nanotubes de carbone fonctionnalisés.
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Amrous, Ania. "Etude d'auto-assemblages moléculaires sur surfaces isolantes par microscopie à force atomique en mode non-contact sous ultravide à température ambiante." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4368.
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Dans ce rapport de thèse, nous présentons les résultats obtenus avec la croissance d'assemblages supramoléculaires hautement cristallins et stables à température ambiante sur des surfaces isolantes d'halogénures d'alcalins. L'objectif de cette étude est de caractériser structurellement ces réseaux auto-assemblés et de mettre en évidence l'ensemble des forces d'interaction mises en œuvre dans les processus de croissance et de diffusion, en combinant la microscopie à force atomique en mode non contact (nc-AFM) sous ultravide et des calculs théoriques basés sur la théorie de la fonctionnelle de la densité (DFT) et la dynamique moléculaire. Nous montrons comment des paramètres bien définis concernant le choix de la molécule d'une part tels que sa taille, sa forme, sa symétrie, sa flexibilité et sa fonctionnalité, et le choix du substrat d'autre part, influent sur la morphologie de croissance et permettent de contrôler les propriétés de diffusion des molécules en surface et donc la structure supramoléculaire résultanteIn this thesis, we report the results obtained with the growth of highly crystalline and stable supramolecular assemblies at room temperature on insulating surfaces of bulk alkali halides single crystals. The objective of this study is to structurally characterize these self-assembled networks and understand all the interaction forces involved in the growth and diffusion processes. This is performed by joint non-contact atomic force microscopy (nc-AFM) experiments in ultrahigh vacuum and theoretical calculations based on density functional theory (DFT) and molecular dynamics. We show how well-defined parameters for the choice of the molecule on the one hand such as size, shape, symmetry, flexibility and functionality, and the choice of the substrate on the other hand, influence the morphology growth and serve to steer the structure and diffusion properties of such systems
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Pawlak, Rémy. "Auto-assemblage et polymérisation 2D de molécules organiques en surface." Phd thesis, Université Paul Cézanne - Aix-Marseille III, 2010. http://tel.archives-ouvertes.fr/tel-00472617.
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Ce travail présente la formation et la caractérisation sous ultravide de monocouches moléculaires issu de l'auto-assemblage et de la polymérisation de molécules organiques (hexahydroxy triphenyléne-HHTP et acide diborique benzoique-BDBA) sur des surfaces monocristallines métalliques et isolantes. L'adsorption de molécules HHTP sur Ag(111) donne lieu à plusieurs réseaux moléculaires dépendants de la température. Cette étude, menée par microscopie à effet tunnel (STM), montre qu'un réseau robuste est obtenu suite à la déshydrogénation, activée thermiquement, des groupes alcool périphériques. Cela induit la formation de liaisons hydrogène entre les fonctions alcools et cétones ainsi obtenues. L'étude STM de molécules de BDBA vapo-déposées sur Ag(111) a démontrée la formation d'architectures bidimensionnelles étendues, liées de manière covalente, suite à la polymérisation des précurseurs en surface. Un résultat similaire a pu être obtenu par la copolymérisation des molécules de BDBA et d'HHTP. Ces polymères nanoporeux s'étendent en monocouche et présentent une stabilité en température exceptionnelle. Enfin, l'étude de BDBA sur le substrat isolant de KCl, menée par microscopie à force atomique en mode non contact (nc-AFM), montre un auto-assemblage étendu par des liaisons hydrogène, et met en évidence le rôle décisif de la nature chimique du substrat sur la faisabilité de la polymérisation de ces molécules en surface. L'approche développée dans ce travail, mettant en jeu des réactions chimiques en surface, constitue une voie nouvelle pour la conception de nano-architectures moléculaires originales et robustes sur surfaces.
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Vernisse, Loranne. "Étude par microscopie à effet tunnel sous ultra-vide et à basse température de complexes de ruthénium." Toulouse 3, 2014. http://thesesups.ups-tlse.fr/2421/.
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Se servir de molécules afin d'exécuter des fonctions équivalentes à celles de composants utilisés en microélectronique est l'un des défis actuels des nanosciences et de l'électronique moléculaire. L'instrument de choix pour observer ces molécules uniques et prédire leur comportement est le microscope à effet tunnel (STM) sous ultravide à très basse température. Cette thèse s'inscrit dans un projet visant à terme à synthétiser et à observer une molécule à quatre centres de ruthénium capable d'exécuter une fonction logique. Nous avons pris le parti d'étudier les molécules issues des premières étapes dans la synthèse de ce composé. Celles-ci sont des systèmes 3D constituées d'un ou de deux atomes de ruthénium et ont été déposées sur des surfaces métalliques telles que l'Ag(111), le Cu(111) ou l'Au(111) ou sur de fines couches isolantes de NaCl. Deux grands types de molécules ont été étudiés : les unes constituées d'atomes de ruthénium au degré d'oxydation III et les autres d'atomes de ruthénium au degré d'oxydation II. Des caractéristiques spécifiques à chaque type de molécule ont été mises en évidence, notamment en termes de propriétés électroniques. Des manipulations sous pointe ont également été effectuées afin de sonder les géométries d'adsorption observées. À terme, ces investigations devront se poursuivre par la mesure de l'état de charge d'un atome métallique dans une molécule extrêmement complexe. Pour anticiper ces mesures, des molécules " modèles " à base de pérylène ont été étudiées. Les résultats montrent que ces dérivés sont tout à fait adaptés à ce type d'expérience et que suivant les groupements utilisés, il est possible de déprotoner la molécule pour favoriser l'apparition de charges locales et fabriquer sous pointe un objet de test idéalUsing molecules able to execute functions found in microelectronic components is one of the current challenges of nanosciences and molecular electronics. The most suited technique to observe single molecules and predict their behavior is Scanning Tunneling Microscope (STM) in ultra-high vacuum and at low temperature. This thesis is a part of a project dedicated to the synthesis and observation of a molecule composed by four ruthenium cores and able to act as a molecular logic gate. We choose to investigate different molecules which come from the first steps in the synthesis of this compound. They are 3D systems composed by one or two ruthenium cores and were adsorbed on metallic surfaces (as Ag(111), Cu(111) and Au(111)) as well as on ultrathin films of NaCl. Two kinds of molecules were studied: the first ones are composed by ruthenium atoms with an oxidation state of III and the other ones have ruthenium atoms with an oxidation state of II. Specific behaviors of each type of molecules are highlighted, concerning particularly their electronic properties. Manipulations using the STM tip were also performed to explore the adsorption geometries. In the future, these investigations should carry on with the charge state measurement on a metallic atom in an extremely complex molecule. The first results performed on model molecules show that perylene derivative compounds are fully adapted to this type of measurements. Moreover, according to the peripheral group, it is possible to deprotonate the molecule to favor the presence of local charges and create a model system under the STM tip
Book chapters on the topic "Nc-AFM"
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Giessibl, Franz J. "Principle of NC-AFM." In Noncontact Atomic Force Microscopy, 11–46. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-56019-4_2.
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Sugawara, Yasuhiro. "NC-AFM Imaging of Adsorbed Molecules." In Noncontact Atomic Force Microscopy, 183–92. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-56019-4_11.
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Jelínek, P. "Theoretical Challenges of Simultaneous nc-AFM/STM Experiments." In Imaging and Manipulation of Adsorbates Using Dynamic Force Microscopy, 81–92. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-17401-3_5.
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Ke, San-Huang, Tsuyoshi Uda, Kiyoyuki Terakura, Ruben Pérez, and Ivan Štich. "Chemical Interaction in NC-AFM on Semiconductor Surfaces." In Noncontact Atomic Force Microscopy, 279–304. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-56019-4_16.
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Hapala, P., M. Ondráček, O. Stetsovych, M. Švec, and P. Jelínek. "Simultaneous nc-AFM/STM Measurements with Atomic Resolution." In Noncontact Atomic Force Microscopy, 29–49. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-15588-3_3.
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Barth, Clemens. "Defects on Bulk MgO(001) Imaged by nc-AFM." In Defects at Oxide Surfaces, 215–39. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-14367-5_7.
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Pang, Chi Lun, and Geoff Thornton. "NC-AFM Imaging of Surface Reconstructions and Metal Growth on Oxides." In Noncontact Atomic Force Microscopy, 147–65. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-56019-4_9.
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Trevethan, T., N. Martsinovich, L. Kantorovich, and A. L. Shluger. "Multi-Scale Modelling of NC-AFM Imaging and Manipulation at Insulating Surfaces." In Noncontact Atomic Force Microscopy, 251–73. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-01495-6_12.
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Heyde, M., G. H. Simon, and T. König. "Study of Thin Oxide Films with NC-AFM: Atomically Resolved Imaging and Beyond." In Noncontact Atomic Force Microscopy, 143–67. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-01495-6_7.
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Arai, Toyoko, and Masahiko Tomitori. "Bias Dependence of NC-AFM Images and Tunneling Current Variations on Semiconductor Surfaces." In Noncontact Atomic Force Microscopy, 79–92. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-56019-4_4.
Full textConference papers on the topic "Nc-AFM"
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Burson, Kristen M., Mahito Yamamoto, and William G. Cullen. "High Resolution Microscopy of SiO2 and the Structure of SiO2-Supported Graphene." In ASME 2011 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/detc2011-48737.
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Graphene has attracted great interest due to its exceptional electrical, mechanical, and chemical properties since its discovery in 2004. Since its first realization, the substrate of choice for graphene exfoliation has been Si wafer with approximately 300 nm thick SiO2 dielectric layer, because it allows 1) direct optical detection of monolayer flakes, and 2) a convenient back gate with dielectric for controlling carrier density in the graphene. However, the amorphous structure of SiO2 and its associated surface roughness has led to ongoing controversy in determining the structure of SiO2-supported graphene. The conductivity of graphene allows scanning tunneling microscopy (STM) to be used to measure its topography, generally allowing its structure to be atomically resolved. In contrast, the insulating SiO2 must be probed with atomic force microscopy (AFM), and this is often done using ambient tapping-mode AFM. STM measurements of graphene on SiO2 generally show greater roughness and finer corrugation than is seen in AFM measurements of SiO2, and this has been interpreted as evidence for “intrinsic” corrugation of the graphene. However, when the energetics of adhesion and elasticity are considered, the idea of intrinsic structure becomes quite controversial for graphene supported on a substrate. Here we show that UHV non-contact AFM (NC-AFM) measurement of SiO2 reveals structure unresolved in previous measurements, and shows both greater roughness and smaller lateral feature size than seen for graphene measured by STM. High-resolution measurement of the SiO2 topography enables an analysis based on the energetics of graphene bending and adhesion, showing that the graphene structure is highly conformal to the SiO2 beneath it. The topographies reported here contrast the atomically-flat crystalline surfaces used in benchmark NC-AFM measurements. They pose unique challenges for measurement resolution, and highlight the very different physical mechanisms which determine resolution in STM vs. NC-AFM. We discuss these issues and our recent efforts at quantitative modeling of the imaging process, with particular focus on the role of van der Waals forces and their contribution to the image signal.
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Radu, G. "Damping Contribution in the Interaction between Probe and Ligand-Stabilized Clusters in NC-AFM." In SCANNING TUNNELING MICROSCOPY/SPECTROSCOPY AND RELATED TECHNIQUES: 12th International Conference STM'03. AIP, 2003. http://dx.doi.org/10.1063/1.1639800.
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Zhao, Wei, and Xiaoping Qian. "Mathematical Morphology in Multi-Dexel Representation." In ASME 2009 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/detc2009-87722.
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Mathematical morphology provides a set-theoretic approach for spatial structure analysis and is particularly useful for describing the spatial relationship between a tool under motion and the part surface. However, its usage in three-dimension has so far been limited in part due to its computational complexity. This paper presents a multi-dexel based computer implementation of morphology operations. Three dimensional objects (tools and parts) are represented as collections of dexels (depth elements) in multiple directions. Morphology operations such as dilation and erosion are then converted to a series of 1D set operations in each direction. We show that our definition of multi-dexel is formal and our implementation is complete. We present our implementation results on three morphological applications: AFM image simulation, noise removal in 3D mesh, and NC path generation.
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Pishkenari, Hossein Nejat, and Ali Meghdari. "The Atomic-Scale Hysteresis in Non Contact Atomic Force Microscopy." In ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis. ASMEDC, 2010. http://dx.doi.org/10.1115/esda2010-24683.
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In this research, the hysteresis in the tip-sample interaction force in noncontact force microscopy (NC-AFM) is measured with the aid of atomistic dynamics simulations. The observed hystersis in the interaction force and displacement of the system atoms leads to the loss of energy during imaging of the sample surface. Using molecular dynamics simulations it is shown that the mechanism of the energy dissipation occurs due to bistabilities caused by atomic jumps of the surface and tip atoms in the contact region. The conducted simulations demonstrate that when a gold coated nano probe is brought close to the Au (001) surface, the tip apex atom jumps to the surface; and instantaneously, four surface atoms jump away from the surface toward the tip apex atom. Along this line, particular attention is dedicated to the dependency of the energy loss to different parameters such as the environment temperature, the tip orientation, the surface plane direction, the system size, the distance of the closest approach and the tip oscillation frequency.