Atomic-resolution images of radiation damage in KBr

Bennewitz, Roland; Schär, S.; Barwich, V.; Pfeiffer, Olivier; Meyer, Ernst; Krok, Franciszek; Such, Bartosz; Kolodzej, J.; Szymoński, Marek

doi:10.1016/s0039-6028(00)01053-0

Cited by 74 publications

(54 citation statements)

References 14 publications

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“…However, the low concentration and high mobility of vacancies and some adsorbed species prevent their observation by an NC-SFM. Stable aggregates of several divacancies have recently been observed on the KBr surface (Bennewitz et al, 2001). Atom-size impurities have been observed on the CaF 2 (111) surface after surface chemical reactions (Reichling and Barth, 1999).…”

Section: Nacl Thin Films On Cu(111) Surfacementioning

confidence: 99%

Theories of scanning probe microscopes at the atomic scale

2003

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Significant progress has been made both in experimentation and in theoretical modeling of scanning probe microscopy. The theoretical models used to analyze and interpret experimental scanning probe microscope (SPM) images and spectroscopic data now provide information not only about the surface, but also the probe tip and physical changes occurring during the scanning process. The aim of this review is to discuss and compare the present status of computational modeling of two of the most popular SPM methods-scanning tunneling microscopy and scanning force microscopy-in conjunction with their applications to studies of surface structure and properties with atomic resolution. In the context of these atomic-scale applications, for the scanning force microscope (SFM), this review focuses primarily on recent noncontact SFM (NC-SFM) results. After a brief introduction to the experimental techniques and the main factors determining image formation, the authors consider the theoretical models developed for the scanning tunneling microscope (STM) and the SFM. Both techniques are treated from the same general perspective of a sharp tip interacting with the surface-the only difference being that the control parameter in the STM is the tunneling current and in the SFM it is the force. The existing methods for calculating STM and SFM images are described and illustrated using numerous examples, primarily from the authors' own simulations, but also from the literature. Theoretical and practical aspects of the techniques applied in STM and SFM modeling are compared. Finally, the authors discuss modeling as it relates to SPM applications in studying surface properties, such as adsorption, point defects, spin manipulation, and phonon excitation. CONTENTS

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Section: Nacl Thin Films On Cu(111) Surfacementioning

confidence: 99%

Theories of scanning probe microscopes at the atomic scale

2003

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“…Previous noncontact SFM studies of this system demonstrated atomic resolution, [15][16][17] but here we present site-specific force curves over the two sublattices and compare them to simulations for several plausible model tips. We first describe atomically resolved images and site-specific frequency versus distance measurements.…”

Section: Introductionmentioning

confidence: 99%

Site-specific force-distance characteristics on NaCl(001): Measurements versus atomistic simulations

et al. 2006

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A scanning force microscope was used to measure the frequency shift above various atomic sites on a NaCl͑001͒ surface at 7 K. The data was converted to force and compared to the results of atomistic simulations using model NaCl and MgO tips. We find that the NaCl tip demonstrates better agreement in the magnitude of the forces in experiments, supporting the observation that the tip first came into contact with the sample. Using the MgO tip as a model of the originally oxidized silicon tip, we further demonstrate a possible mechanism for tip contamination at low temperatures.

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“…Generally, after the initial desorption of a surface atom, predominantly at kink sites, 5,8 an unzipping process is initiated along a step. In the case of this study, the unzipping may be interrupted by the presence of metal nanoparticles which physically obstruct the process.…”

Section: Fig 2 Nc-afm Topography Measurements Of Rectangular Pits Imentioning

confidence: 99%

“…3 Moreover, the recent development of noncontact atomic force microscopy 4 ͑NC-AFM͒ has opened up the possibility of measuring the topography of modified insulators with atomic resolution. 5 This is of great importance since the influence of surface topography on the desorption process leading to surface modification remains largely unknown. 1 Through excitation by electrons, 1 photons, 6 or ions, 7 the desorption of atoms from ionic crystal surfaces is induced by the formation of Frenkel defects in the bulk ͑F and H centers͒, which diffuse and recombine with the surface.…”

mentioning

confidence: 99%

Use of an electron-beam evaporator for the creation of nanostructured pits in an insulating surface

Mativetsky

Miyahara

Fostner

et al. 2006

Applied Physics Letters

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We demonstrate a method for creating monatomic-depth rectangular pits of controlled size in an alkali halide surface by using an electron-beam evaporator. Atomic resolution noncontact atomic force microscopy is used to characterize the structure and size distribution of the pits, with mean side lengths ranging from 6.5 to 20 nm. It is also demonstrated that metal nanoparticles can be used to nucleate the growth of pits, resulting in pits with metal nanoparticles inside. © 2006 American Institute of Physics. ͓DOI: 10.1063/1.2210288͔ While surface modifications induced by electronic transitions have been of fundamental interest for several decades, 1,2 there is renewed interest in the field because of its relevance to nanofabrication. 3 Moreover, the recent development of noncontact atomic force microscopy 4 ͑NC-AFM͒ has opened up the possibility of measuring the topography of modified insulators with atomic resolution. 5 This is of great importance since the influence of surface topography on the desorption process leading to surface modification remains largely unknown. 1 Through excitation by electrons, 1 photons, 6 or ions, 7 the desorption of atoms from ionic crystal surfaces is induced by the formation of Frenkel defects in the bulk ͑F and H centers͒, which diffuse and recombine with the surface. 1 At the first stages of the typically layer-by-layer surface removal, monatomic-depth rectangular pits are formed, which are several nanometers in size. Recently, these pits have been used to trap small numbers of SubPc molecules, 3 an important step towards assembling a molecular electronic device on an insulating substrate. These well defined surface features may also serve to control the nucleation of metal nanostructures at surfaces. 6 In this letter, we report on the use of an electronbeam evaporator as a source of charged particles for creating arrays of nanostructured pits and metal nanoparticles inside pits on a KBr ͑001͒ surface.All of the sample preparation and characterization was performed in ultrahigh vacuum ͑base pressure Ͻ4 ϫ 10 −8 Pa͒. The KBr surfaces were prepared by cleaving a crystal ͑Korth Kristalle, Germany͒ in situ along the ͑001͒ plane and then heating for 1 h at 150°C, in order to remove any residual surface charge. An Oxford Applied Research EGN4 electron-beam evaporator was used for the pit creation and metal deposition. During operation, charged particles are emitted as a result of the ionization of residual gas in the vacuum chamber, the ionization of target material, and the production of low energy electrons. To reduce the amount of charge impinging on the sample during evaporation, the evaporator is fitted with a grid held at 2 kV. With this setup, extremely small current densities are accessible ͑Ͻ500 pA/ cm 2 ͒, making it possible to finely tune the irradiation dose to the sample. Tantalum ͑Alfa Aesar, 99.95%͒ was used as the evaporator target material because its high melting point enables the use of a wide range of evaporator powers, and hence current densities. The pits were cre...

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Atomic-resolution images of radiation damage in KBr

Cited by 74 publications

References 14 publications

Theories of scanning probe microscopes at the atomic scale

Theories of scanning probe microscopes at the atomic scale

Site-specific force-distance characteristics on NaCl(001): Measurements versus atomistic simulations

Use of an electron-beam evaporator for the creation of nanostructured pits in an insulating surface

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