Electrochemical etching of metal wires in low-stress electric contact using a liquid metal electrode to fabricate tips for scanning tunneling microscopy

The three-dimensional shape relaxation of gold nanostructures was studied by scanning tunneling microscopy in real time and at ambient conditions. The nanostructures were fabricated on a Au(100) single crystal by a two step-process: electrochemical etching to produced a rough surface, followed by thermal annealing. The nanostructures can be described as mounds having small semicircular facets that shrink in time, peeling away layer by layer as a result of the sudden temperature change and evolving towards thermodynamic equilibrium. A model developed by Uwaha is used to describe the dynamic evolution of the peeling layers, where good agreement was found despite the presence of adsorbates due to ambient exposure.

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An electrochemical etching procedure for fabricating scanning tunneling microscopy and atom-probe field-ion microscopy tips

Metals and Materials International ◽

10.1007/bf03027195 ◽

2003 ◽

Vol 9 (4) ◽

pp. 399-404 ◽

Cited By ~ 12

Author(s):

Yeong-Cheol Kim ◽

David N. Seidman

Keyword(s):

Scanning Tunneling Microscopy ◽

Electrochemical Etching ◽

Atom Probe ◽

Scanning Tunneling ◽

Tunneling Microscopy ◽

Probe Field ◽

Field Ion Microscopy ◽

Ion Microscopy

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Scanning Tunneling Microscopy Studies of Porous and Oxidized Zn

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.326-328.373 ◽

2006 ◽

Vol 326-328 ◽

pp. 373-376

Author(s):

Sung Sik Chang ◽

Akira Sakai

Keyword(s):

Scanning Tunneling Microscopy ◽

Band Gap ◽

Electrochemical Etching ◽

Wide Band ◽

Scanning Tunneling Spectroscopy ◽

Shallow Donor ◽

Scanning Tunneling ◽

Tunneling Microscopy ◽

Wide Band Gap ◽

Donor States

This paper reports the scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) studies of porous Zn (p- Zn) prepared by electrochemical etching. Further, the post annealing of the p- Zn is carried out and STM/STS investigations are also performed. STM studies of these samples reveal the porous structure and display small, pseudo-spherical shaped crystals in the range of 2 and 100 nm, 2 and 50 nm, and similar average corrugation of 9 nm for p- Zn and oxidized p-Zn. STS analysis of freshly prepared p- Zn shows a band gap of 2.4 eV along with metallic conductance behavior. However, oxidized p- Zn reveals a distinct wide band gap (3 eV) and shows shallow donor states near the conduction band.

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A study on α-RuCl3 crystal structure by scanning tunneling microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100152124 ◽

1989 ◽

Vol 47 ◽

pp. 30-31

Author(s):

H.-J. Cantow ◽

H. Hillebrecht ◽

S. Magonov ◽

H. W. Rotter ◽

G. Thiele

Keyword(s):

Crystal Structure ◽

Density Distribution ◽

Scanning Tunneling Microscopy ◽

Electron Density ◽

Structure Determination ◽

Electron Density Distribution ◽

Scanning Tunneling ◽

Monoclinic Space Group ◽

Tunneling Microscopy ◽

X Ray

From X-ray analysis, the conclusions are drawn from averaged molecular informations. Thus, limitations are caused when analyzing systems whose symmetry is reduced due to interatomic interactions. In contrast, scanning tunneling microscopy (STM) directly images atomic scale surface electron density distribution, with a resolution up to fractions of Angstrom units. The crucial point is the correlation between the electron density distribution and the localization of individual atoms, which is reasonable in many cases. Thus, the use of STM images for crystal structure determination may be permitted. We tried to apply RuCl3 - a layered material with semiconductive properties - for such STM studies. From the X-ray analysis it has been assumed that α-form of this compound crystallizes in the monoclinic space group C2/m (AICI3 type). The chlorine atoms form an almost undistorted cubic closed package while Ru occupies 2/3 of the octahedral holes in every second layer building up a plane hexagon net (graphite net). Idealizing the arrangement of the chlorines a hexagonal symmetry would be expected. X-ray structure determination of isotypic compounds e.g. IrBr3 leads only to averaged positions of the metal atoms as there exist extended stacking faults of the metal layers.

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Roughness measurements of nonlinear optical polymer films by scanning tunneling microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100152082 ◽

1989 ◽

Vol 47 ◽

pp. 22-23

Author(s):

I. H. Musselman ◽

R.-T. Chen ◽

P. E. Russell

Keyword(s):

Surface Roughness ◽

Scanning Tunneling Microscopy ◽

Nonlinear Optical ◽

Polymer Surface ◽

Light Extinction ◽

Scanning Tunneling ◽

Silicon Substrates ◽

Tunneling Microscopy ◽

Optical Polymer ◽

Total Light

Scanning tunneling microscopy (STM) has been used to characterize the surface roughness of nonlinear optical (NLO) polymers. A review of STM of polymer surfaces is included in this volume. The NLO polymers are instrumental in the development of electrooptical waveguide devices, the most fundamental of which is the modulator. The most common modulator design is the Mach Zehnder interferometer, in which the input light is split into two legs and then recombined into a common output within the two dimensional waveguide. A π phase retardation, resulting in total light extinction at the output of the interferometer, can be achieved by changing the refractive index of one leg with respect to the other using the electrooptic effect. For best device performance, it is essential that the NLO polymer exhibit minimal surface roughness in order to reduce light scattering. Scanning tunneling microscopy, with its high lateral and vertical resolution, is capable of quantifying the NLO polymer surface roughness induced by processing. Results are presented below in which STM was used to measure the surface roughness of films produced by spin-coating NLO-active polymers onto silicon substrates.

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Practical applications of scanning tunneling microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100152069 ◽

1989 ◽

Vol 47 ◽

pp. 18-19

Author(s):

D. R. Denley

Keyword(s):

High Resolution ◽

Scanning Tunneling Microscopy ◽

Quantitative Information ◽

Digital Data ◽

Scanning Tunneling ◽

Ambient Atmosphere ◽

Tunneling Microscopy ◽

Clear Trend ◽

Practical Applications ◽

Promising Tool

Scanning tunneling microscopy (STM) has recently been introduced as a promising tool for analyzing surface atomic structure. We have used STM for its extremely high resolution (especially the direction normal to surfaces) and its ability for imaging in ambient atmosphere. We have examined surfaces of metals, semiconductors, and molecules deposited on these materials to achieve atomic resolution in favorable cases.When the high resolution capability is coupled with digital data acquisition, it is simple to get quantitative information on surface texture. This is illustrated for the measurement of surface roughness of evaporated gold films as a function of deposition temperature and annealing time in Figure 1. These results show a clear trend for which the roughness, as well as the experimental deviance of the roughness is found to be minimal for evaporation at 300°C. It is also possible to contrast different measures of roughness.

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Scanning tunneling microscopy of polymers: A status report

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100153622 ◽

1989 ◽

Vol 47 ◽

pp. 330-331

Author(s):

P.E. Russell ◽

I.H. Musselman

Keyword(s):

High Resolution ◽

Scanning Tunneling Microscopy ◽

Sample Surface ◽

Atomic Scale ◽

Constant Current ◽

Scanning Tunneling ◽

Status Report ◽

Tunneling Microscopy ◽

Research Issues ◽

Wide Range

Scanning tunneling microscopy (STM) has evolved rapidly in the past few years. Major developments have occurred in instrumentation, theory, and in a wide range of applications. In this paper, an overview of the application of STM and related techniques to polymers will be given, followed by a discussion of current research issues and prospects for future developments. The application of STM to polymers can be conveniently divided into the following subject areas: atomic scale imaging of uncoated polymer structures; topographic imaging and metrology of man-made polymer structures; and modification of polymer structures. Since many polymers are poor electrical conductors and hence unsuitable for use as a tunneling electrode, the related atomic force microscopy (AFM) technique which is capable of imaging both conductors and insulators has also been applied to polymers.The STM is well known for its high resolution capabilities in the x, y and z axes (Å in x andy and sub-Å in z). In addition to high resolution capabilities, the STM technique provides true three dimensional information in the constant current mode. In this mode, the STM tip is held at a fixed tunneling current (and a fixed bias voltage) and hence a fixed height above the sample surface while scanning across the sample surface.

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