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Seizo Morita - One of the best experts on this subject based on the ideXlab platform.

  • Non-Contact AFM.
    Journal of physics. Condensed matter : an Institute of Physics journal, 2012
    Co-Authors: Franz J. Giessibl, Seizo Morita
    Abstract:

    This special issue is focussed on high resolution Non-Contact atomic force microscopy (AFM). Non-Contact atomic force microscopy was established approximately 15 years ago as a tool to image conducting and insulating surfaces with atomic resolution. Since 1998, an annual international conference has taken place, and although the proceedings of these conferences are a useful source of information, several key developments warrant devoting a special issue to this subject. In the theoretic field, the possibility of supplementing established techniques such as scanning tunneling microscopy (STM) and Kelvin probe microscopy with atomically resolved force micrsoscopy poses many challenges in the calculation of contrast and contrast reversal. The surface science of insulators, self-assembled monolayers and adsorbates on insulators is a fruitful field for the application of Non-Contact AFM: several articles in this issue are devoted to these subjects. Atomic imaging and manipulation have been pioneered using STM, but because AFM allows the measurement of forces, AFM has had a profound impact in this field as well. Three-dimensional force spectroscopy has allowed many important insights into surface science. In this issue a combined 3D tunneling and force microscopy is introduced. Non-Contact AFM typically uses frequency modulation to measure force gradients and was initially used mainly in a vacuum. As can be seen in this issue, frequency modulation is now also used in ambient conditions, allowing better spatial and force resolution. We thank all of the contributors for their time and efforts in making this special issue possible. We are also very grateful to the staff of IOP Publishing for handling the administrative aspects and for steering the refereeing process. Non-Contact AFM contents Relation between the chemical force and the tunnelling current in atomic point contacts: a simple model Pavel Jelinek, Martin Ondracek and Fernando Flores Theoretical simulation of Kelvin probe force microscopy for Si surfaces by taking account of chemical forces Masaru Tsukada, Akira Masago and Mamoru Shimizu Reversal of atomic contrast in scanning probe microscopy on (111) metal surfaces M Ondracek, C Gonzalez and P Jelinek Mechanical properties of H2Pc self-assembled monolayers at the single molecule level by noncontact atomic force microscopy Han-Qing Mao, Na Li, Xi Chen and Qi-Kun Xue High-resolution imaging of C60 molecules using tuning-fork-based Non-Contact atomic force microscopy R Pawlak, S Kawai, S Fremy, T Glatzel and E Meyer NC-AFM contrast formation on the calcite (101¯4) surface Philipp Rahe, Jens Schutte and Angelika Kuhnle Imaging and manipulation of adatoms on an alumina surface by noncontact atomic force microscopy G H Simon, M Heyde and H-J Freund Three-dimensional scanning force/tunneling spectroscopy at room temperature Yoshiaki Sugimoto, Keiichi Ueda, Masayuki Abe and Seizo Morita Imaging and manipulation of the Si(100) surface by small-amplitude NC-AFM at zero and very low applied biasA Sweetman, R Danza, S Gangopadhyay and P Moriarty Manipulation of individual water molecules on CeO2(111) S Torbrugge, O Custance, S Morita and M Reichling FM-AFM imaging of a commercial polyethylene film immersed in n-dodecaneTakumi Hiasa, Tomoki Sugihara, Kenjiro Kimura and Hiroshi Onishi

  • Atomic structure of Ge clusters on Si(111)-(7 × 7) by Non-Contact AFM
    Nanotechnology, 2007
    Co-Authors: Yoshiaki Sugimoto, Ryuji Nishi, Masayuki Abe, Seizo Morita
    Abstract:

    We present Non-Contact (NC) AFM results of Ge clusters on a Si(111)-(7 × 7) reconstructed surface. The low temperature NC-AFM allows us to directly observe the atomic structure of the Ge clusters on the Si(111). The Ge clusters reside in the middle of a half unit cell in the (7 × 7) reconstruction surface and they are ~1.4 A higher than the Si adatoms. By direct NC-AFM observation, the features of the Ge clusters on the Si(111) became clear. First, the Ge atoms reside in spaces between Si adatoms and on the Si/Ge atoms on the Si(111). Second, the Si adatoms shift from their original position through Ge adsorption, and interact with the Ge atoms accompanied by surface relaxation and a change in their spatial heights. In addition, the interatomic distance between the Ge atoms inside the clusters is approximately 4.0 A, which is larger than that between the Ge atoms in the bulk (2.4 A). Our NC-AFM results of Ge clusters provide valuable information for the basic study of clusters on semiconductor surfaces and may be useful for the manipulation and assembly of clusters for the realization of diverse nanostructures at the atomic level.

  • Non-Contact AFM observation of the (3×3) to (3 × 3) phase transition on Sn/Ge(1 1 1) and Sn/Si(1 1 1) surfaces
    Applied Surface Science, 2007
    Co-Authors: Ryuji Nishi, Yoshiaki Sugimoto, Seizo Morita
    Abstract:

    Abstract The ( 3 × 3 ) to (3 × 3) phase transition in Sn/Ge(1 1 1)-( 3 × 3 )R30° and Sn/Si(1 1 1)-( 3 × 3 )R30° systems was investigated for the first time using a Non-Contact atomic force microscope (NC-AFM). Observations show the occurrence of the phase transition with small (3 × 3) domains on the Sn/Ge(1 1 1) surface at low temperatures of 78 and 6 K. However, no evidence was found to support the presence of the phase transition for the Sn/Si(1 1 1) system, even when the temperature was lowered to 6 K. The (3 × 3) domains present two patterns, one hexagonal and the other honeycomb, depending on the tip to sample distance.

  • Study on topographic images of Sn/Si(1 1 1)-(√3 × √3)R30° surface by Non-Contact AFM
    Surface Science, 2006
    Co-Authors: Yoshiaki Sugimoto, Ryuji Nishi, Seizo Morita
    Abstract:

    Abstract Various contrast of topographic images depending on a state of a tip apex on Sn/Si(1 1 1)-(√3 × √3)R30° surface was investigated using a low temperature Non-Contact AFM. With the type A tip, the image of the ring-type Sn, composed of six Sn atoms surrounding substitutional Si defect, was observed when the frequency shift (∣Δf∣) was small (the tip-sample distance, Ztip-sample, was long), while the ring-type Sn was not observed and all the Sn atoms have the same contrast when ∣Δf∣ was large (Ztip-sample was short). On the other hand, with the type B tip, modified from the type A tip by the tip-sample contact, the image of the ring-type Sn atoms was not observed regardless of variation of Δf. It is the first experimental result on the low temperature NC-AFM observation in the Sn/Si(1 1 1) system, which depends on short-range chemical bonding force or electrostatic force acting between the tip and the sample surface. In addition, the substitutional Si defects on the surface were seen as a dim spot or were not seen, also depending on the tip state.

  • Non‐contact AFM images measured on Si(111)√3×√3‐Ag and Ag(111) surfaces
    Surface and Interface Analysis, 1999
    Co-Authors: Yasuhiro Sugawara, T. Minobe, Shigeki Orisaka, Takayuki Uchihashi, T. Tsukamoto, Seizo Morita
    Abstract:

    We investigated the force interactions between a Si tip and a Si(111)√3 × √3-Ag surface, as well as between a Si tip and an Ag(111) surface, using Non-Contact atomic force microscopy (AFM) operating in ultrahigh vacuum (UHV). The AFM images on the Si(111)√3 × √3-Ag surface showed three types of contrast that depended on the distance between a tip and a sample surface: at a tip-sample distance of 0.1-03 nm the AFM image showed a honeycomb arrangement, at a tip-sample distance of 0-0.05 nm the image showed the periodic structure of a triangle, consisting of three bright spots with relatively strong contrast, but at a distance of 0.05-0.1 nm the image contrast seemed to be intermediary between the other two types of contrast. When the tip is far from the sample surface, the tip-sample interaction force is dominated by physical bonding interactions such as Coulomb and/or van der Waals forces between the tip apex Si atom and the Ag trimer on the sample surface. On the other hand, just before contact, the tip-sample interaction force is dominated by chemical bonding interaction due to the onset of hybridization between the dangling bond of the tip apex Si atom and the orbital of the Si-Ag covalent bond on the surface. Furthermore, atomic resolution imaging of a pure metallic surface of Ag(111) was achieved, suggesting that Non-Contact AFM has potential for the investigation of a pure metallic surface.

Marek Szymonski - One of the best experts on this subject based on the ideXlab platform.

  • Higher Acenes by On‐Surface Dehydrogenation: From Heptacene to Undecacene
    Angewandte Chemie International Edition, 2018
    Co-Authors: Rafal Zuzak, Ruth Dorel, Marek Kolmer, Marek Szymonski, Szymon Godlewski, Antonio M. Echavarren
    Abstract:

    A unified approach to the synthesis of the series of higher acenes up to previously unreported undecacene has been developed through the on-surface dehydrogenation of partially saturated precursors. These molecules could be converted into the parent acenes by both atomic manipulation with the tip of a scanning tunneling and atomic force microscope (STM/AFM) as well as by on-surface annealing. The structure of the generated acenes has been visualized by high-resolution Non-Contact AFM imaging and the evolution of the transport gap with the increase of the number of fused benzene rings has been determined on the basis of scanning tunneling spectroscopy (STS) measurements.

  • Atomic Force Microscopy for Surface Imaging and Characterization of Supported Nanostructures
    Surface Science Techniques, 2013
    Co-Authors: Franciszek Krok, Bartosz Such, Jacek J. Kolodziej, Marek Szymonski
    Abstract:

    This chapter presents an overview of Atomic Force Microscopy (AFM) principles followed by details on AFM instrumentation. In particular, the frequency modulation method of the Non-Contact AFM (NC-AFM) used in ultra-high vacuum conditions is explained in detail. Then, applications of NC-AFM for an atomic-scale range characterization of semiconductor and isolator surfaces as well as supported nanostructures are introduced.

  • Copper phthalocyanine molecules on an InSb(001) c(8 × 2) surface studied by ultra-high-vacuum STM and Non-Contact AFM
    Nanotechnology, 2007
    Co-Authors: Antoni Tekiel, M. Goryl, Marek Szymonski
    Abstract:

    The surface ordering of copper phthalocyanine (CuPc) molecules deposited onto an InSb(001) c(8 × 2) reconstructed surface has been studied using scanning tunneling microscopy (STM), Non-Contact atomic force microscopy (nc-AFM) and low-energy electron diffraction (LEED). It was found that at room temperature the CuPc molecules are only weakly bound to the InSb surface and the adjacent molecules and consequently they are relatively mobile at submonolayer coverage. STM images show that at the initial stages of growth molecules are assembled in ordered molecular chains parallel to the surface reconstruction rows, i.e. along the [110] crystallographic direction. Furthermore, adsorption of the molecules at step edges is observed. At coverages below 1 ML molecules diffuse at the surface and form two-dimensional islands, which leads to an additional characteristic (n × 3) LEED pattern indicating one-dimensional ordering within the molecular chains. High-resolution STM imaging at negative sample bias reveals a unique structure of the molecular contrast which may be related to the highest occupied molecular orbital (HOMO) of the individual CuPc molecules. For CuPc monolayer coverage submolecular resolution is also obtained for nc-AFM imaging. Finally, examples of single molecule manipulation by the STM tip are given.

  • Non-Contact AFM investigation of influence of freezing process on the surface structure of potato starch granule
    Applied Surface Science, 2000
    Co-Authors: Franciszek Krok, J Szymońska, Piotr Tomasik, Marek Szymonski
    Abstract:

    Abstract To assess the influence of the freezing process on the surface structure of a potato starch granule, a Non-Contact Atomic Force Microscopy (NC-AFM) investigation at ambient conditions has been undertaken. The observations were carried out for dried (oven-dried) and native (air-dried) starch. The obtained AFM images of the native starch granule surface demonstrated it as not uniformly smooth and having rough undulating appearance with layers of adsorbed water which could be removed by oven drying in 130°C. After freezing, the dried starch granule surface still consisted of nodules of about 100 nm in diameter. Significant changes in the granule surface appearance can be seen for dried starch samples frozen with some excess of water as well as for native starch samples frozen with its original water. Then the aggregation and polishing of the granules was observed and their surface revealed a microstructure with distinct ring-like protrusions of about 300 nm in diameter. Our observations tally with the amylopectine “blocket” starch granule structure model proposed in the literature and allowed to conclude that freezing may be a useful tool, among other methods, for modifying starch granule properties.

Yoshiaki Sugimoto - One of the best experts on this subject based on the ideXlab platform.

  • Atomic structure of Ge clusters on Si(111)-(7 × 7) by Non-Contact AFM
    Nanotechnology, 2007
    Co-Authors: Yoshiaki Sugimoto, Ryuji Nishi, Masayuki Abe, Seizo Morita
    Abstract:

    We present Non-Contact (NC) AFM results of Ge clusters on a Si(111)-(7 × 7) reconstructed surface. The low temperature NC-AFM allows us to directly observe the atomic structure of the Ge clusters on the Si(111). The Ge clusters reside in the middle of a half unit cell in the (7 × 7) reconstruction surface and they are ~1.4 A higher than the Si adatoms. By direct NC-AFM observation, the features of the Ge clusters on the Si(111) became clear. First, the Ge atoms reside in spaces between Si adatoms and on the Si/Ge atoms on the Si(111). Second, the Si adatoms shift from their original position through Ge adsorption, and interact with the Ge atoms accompanied by surface relaxation and a change in their spatial heights. In addition, the interatomic distance between the Ge atoms inside the clusters is approximately 4.0 A, which is larger than that between the Ge atoms in the bulk (2.4 A). Our NC-AFM results of Ge clusters provide valuable information for the basic study of clusters on semiconductor surfaces and may be useful for the manipulation and assembly of clusters for the realization of diverse nanostructures at the atomic level.

  • Non-Contact AFM observation of the (3×3) to (3 × 3) phase transition on Sn/Ge(1 1 1) and Sn/Si(1 1 1) surfaces
    Applied Surface Science, 2007
    Co-Authors: Ryuji Nishi, Yoshiaki Sugimoto, Seizo Morita
    Abstract:

    Abstract The ( 3 × 3 ) to (3 × 3) phase transition in Sn/Ge(1 1 1)-( 3 × 3 )R30° and Sn/Si(1 1 1)-( 3 × 3 )R30° systems was investigated for the first time using a Non-Contact atomic force microscope (NC-AFM). Observations show the occurrence of the phase transition with small (3 × 3) domains on the Sn/Ge(1 1 1) surface at low temperatures of 78 and 6 K. However, no evidence was found to support the presence of the phase transition for the Sn/Si(1 1 1) system, even when the temperature was lowered to 6 K. The (3 × 3) domains present two patterns, one hexagonal and the other honeycomb, depending on the tip to sample distance.

  • Study on topographic images of Sn/Si(1 1 1)-(√3 × √3)R30° surface by Non-Contact AFM
    Surface Science, 2006
    Co-Authors: Yoshiaki Sugimoto, Ryuji Nishi, Seizo Morita
    Abstract:

    Abstract Various contrast of topographic images depending on a state of a tip apex on Sn/Si(1 1 1)-(√3 × √3)R30° surface was investigated using a low temperature Non-Contact AFM. With the type A tip, the image of the ring-type Sn, composed of six Sn atoms surrounding substitutional Si defect, was observed when the frequency shift (∣Δf∣) was small (the tip-sample distance, Ztip-sample, was long), while the ring-type Sn was not observed and all the Sn atoms have the same contrast when ∣Δf∣ was large (Ztip-sample was short). On the other hand, with the type B tip, modified from the type A tip by the tip-sample contact, the image of the ring-type Sn atoms was not observed regardless of variation of Δf. It is the first experimental result on the low temperature NC-AFM observation in the Sn/Si(1 1 1) system, which depends on short-range chemical bonding force or electrostatic force acting between the tip and the sample surface. In addition, the substitutional Si defects on the surface were seen as a dim spot or were not seen, also depending on the tip state.

Ryuji Nishi - One of the best experts on this subject based on the ideXlab platform.

  • Atomic structure of Ge clusters on Si(111)-(7 × 7) by Non-Contact AFM
    Nanotechnology, 2007
    Co-Authors: Yoshiaki Sugimoto, Ryuji Nishi, Masayuki Abe, Seizo Morita
    Abstract:

    We present Non-Contact (NC) AFM results of Ge clusters on a Si(111)-(7 × 7) reconstructed surface. The low temperature NC-AFM allows us to directly observe the atomic structure of the Ge clusters on the Si(111). The Ge clusters reside in the middle of a half unit cell in the (7 × 7) reconstruction surface and they are ~1.4 A higher than the Si adatoms. By direct NC-AFM observation, the features of the Ge clusters on the Si(111) became clear. First, the Ge atoms reside in spaces between Si adatoms and on the Si/Ge atoms on the Si(111). Second, the Si adatoms shift from their original position through Ge adsorption, and interact with the Ge atoms accompanied by surface relaxation and a change in their spatial heights. In addition, the interatomic distance between the Ge atoms inside the clusters is approximately 4.0 A, which is larger than that between the Ge atoms in the bulk (2.4 A). Our NC-AFM results of Ge clusters provide valuable information for the basic study of clusters on semiconductor surfaces and may be useful for the manipulation and assembly of clusters for the realization of diverse nanostructures at the atomic level.

  • Non-Contact AFM observation of the (3×3) to (3 × 3) phase transition on Sn/Ge(1 1 1) and Sn/Si(1 1 1) surfaces
    Applied Surface Science, 2007
    Co-Authors: Ryuji Nishi, Yoshiaki Sugimoto, Seizo Morita
    Abstract:

    Abstract The ( 3 × 3 ) to (3 × 3) phase transition in Sn/Ge(1 1 1)-( 3 × 3 )R30° and Sn/Si(1 1 1)-( 3 × 3 )R30° systems was investigated for the first time using a Non-Contact atomic force microscope (NC-AFM). Observations show the occurrence of the phase transition with small (3 × 3) domains on the Sn/Ge(1 1 1) surface at low temperatures of 78 and 6 K. However, no evidence was found to support the presence of the phase transition for the Sn/Si(1 1 1) system, even when the temperature was lowered to 6 K. The (3 × 3) domains present two patterns, one hexagonal and the other honeycomb, depending on the tip to sample distance.

  • Study on topographic images of Sn/Si(1 1 1)-(√3 × √3)R30° surface by Non-Contact AFM
    Surface Science, 2006
    Co-Authors: Yoshiaki Sugimoto, Ryuji Nishi, Seizo Morita
    Abstract:

    Abstract Various contrast of topographic images depending on a state of a tip apex on Sn/Si(1 1 1)-(√3 × √3)R30° surface was investigated using a low temperature Non-Contact AFM. With the type A tip, the image of the ring-type Sn, composed of six Sn atoms surrounding substitutional Si defect, was observed when the frequency shift (∣Δf∣) was small (the tip-sample distance, Ztip-sample, was long), while the ring-type Sn was not observed and all the Sn atoms have the same contrast when ∣Δf∣ was large (Ztip-sample was short). On the other hand, with the type B tip, modified from the type A tip by the tip-sample contact, the image of the ring-type Sn atoms was not observed regardless of variation of Δf. It is the first experimental result on the low temperature NC-AFM observation in the Sn/Si(1 1 1) system, which depends on short-range chemical bonding force or electrostatic force acting between the tip and the sample surface. In addition, the substitutional Si defects on the surface were seen as a dim spot or were not seen, also depending on the tip state.

Rubén Pérez - One of the best experts on this subject based on the ideXlab platform.

  • Reversible short-range electrostatic imaging in frequency modulation atomic force microscopy on metallic surfaces
    Nanotechnology, 2004
    Co-Authors: Peter Dieska, Ivan Stich, Rubén Pérez
    Abstract:

    The mechanism of atomic-scale image formation in Non-Contact AFM on metallic surfaces is analysed using total-energy pseudopotential calculations. Depending on the tip–apex configuration, we find two different imaging modes. Both clean and metal contaminated Si tips provide atomic resolution arising from the very strong covalent tip–sample interaction, in striking similarity with the imaging mechanism found on semiconductor surfaces. A completely new mechanism, reversible short-range electrostatic imaging, due to subtle charge-transfer interactions is identified for oxidized Si tips. Contrary to the strong covalent-bond imaging, this new mechanism causes only negligible surface perturbation and can account for recent experimental results.

  • Tip–surface interactions in atomic force microscopy: reactive vs. metallic surfaces
    Applied Surface Science, 2002
    Co-Authors: Ivan Stich, Peter Dieska, Rubén Pérez
    Abstract:

    Abstract We present ab initio simulations of AFM image formation in the Non-Contact regime for prototypical reactive semiconductor and metal surfaces: InP(1 1 0)-1×1 and Cu(0 0 1). For the reactive surface the effect of tip morphology of the tip apex was also studied. The nature of the tip apex alters the local tip reactivity and can lead to reversal of the apparent AFM surface corrugation. We find that for both semiconductor and metal surfaces the atomic resolution is primarily mediated by a strong chemical-type of interaction between the tip and the surface. This allows for a unified interpretation of the tip–surface interactions in the Non-Contact AFM microscopy.

  • Contrast mechanism in Non-Contact AFM on reactive surfaces
    Applied Surface Science, 1998
    Co-Authors: Rubén Pérez, Mike C. Payne, Ivan Sˇtich, Kiyoyuki Terakura
    Abstract:

    Total-energy pseudopotential calculations are used to study the imaging process in Non-Contact atomic force microscopy on Si(111) surfaces. The atomic resolution seen in the experiments is attributed to the onset of covalent bonding between a localised dangling bond on the atom at the apex of the tip and the dangling bonds on the adatoms in the surface. This interaction dominates the force gradients, which drive the frequency changes used to create the experimental images. Force vs. tip displacement curves provide information about the optimum operation range and show the importance of the relaxation of the tip apex and surface atoms in the understanding of the damping images.

  • First Principles Simulations of Nanoindentation and Atomic Force Microscopy on Silicon Surfaces
    MRS Online Proceedings Library, 1995
    Co-Authors: Rubén Pérez, Mike C. Payne, I. Stich, Kiyoyuki Terakura
    Abstract:

    Total-Energy pseudopotential calculations are used to study both the onset and development of plasticity in nanoindentation experiments and the contrast mechanism in Non-Contact AFM images on Si(111) surfaces. As regards nanoindentation, plastic flow of atoms towards interstitial positions and extrusion of material towards the tip walls, stabilized by the adhesive interactions with the tip, are the dominant mechanisms. These plastic deformations are triggered by the delocalization of the charge induced by the stress in the elastically compressed structure. Atomic resolution contrast in AFM is shown to be clearly enhanced by the partial covalent chemical interaction between the dangling bonds of the adatoms in the surface and the apex atom in the tip. The contrast mechanism can be understood in terms of the coupling between the tip and the charge transfer modes among the different dangling bonds in the surface.