A Surface Raman and Scanning Tunneling Microscopy Study of The Spatial Distribution of Corner-Sharing and Edge-Sharing Octahedra on thermally Oxidized Tungsten

1997 ◽  
Vol 495 ◽  
Author(s):  
Matthew J. Côté ◽  
Corey Radloff ◽  
Joseph M. Osman ◽  
Rebecca Bussjager ◽  
R. Martin Villarica ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Scanning Tunneling Microscopy ◽  
Power Density ◽  
Laser Power ◽  
Laser Power Density ◽  
Qualitative Description ◽  
Scanning Tunneling ◽  
Oxide Surface ◽  
Tunneling Microscopy ◽  
Defect Sites

ABSTRACTWe have measured the dependence of the strength of Raman activity of polycrystalline m-WO3 on spot size at constant laser power density. These data are compared to surface area scaling measurements obtained using scanning tunneling microscopy. We argue that the spatial distribution of scattering centers is the complement of the spatial distribution of crystallographic shear (CS) structures on or near the oxide surface. Our results are consistent with there being an essentially uniform spatial distribution of scattering sites which implies the spatial distribution of defect sites is also uniform. At the laser power density involved and at the defect densities studied, we found no evidence suggesting a large amount of cooperativity in the formation of CS structures. These results suggest a qualitative description of the structure of common oxide surfaces in agreement with a basic assumption of the JMAK theory of first order phase transformations.

Observation of All the Intermediate Steps of a Chemical Reaction on an Oxide Surface by Scanning Tunneling Microscopy

ACS Nano ◽  
2009 ◽  
Vol 3 (3) ◽  
pp. 517-526 ◽  
Author(s):  
Jesper Matthiesen ◽  
Stefan Wendt ◽  
Jonas Ø. Hansen ◽  
Georg K. H. Madsen ◽  
Estephania Lira ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Chemical Reaction ◽  
Scanning Tunneling ◽  
Oxide Surface ◽  
Tunneling Microscopy

Studies of Si Surface Chemistry and Epitaxy Using Scanning Tunneling Microscopy and Spectroscopy

1988 ◽  
Vol 131 ◽  
Author(s):  
Phaedon Avouris ◽  
Robert Wolkow
Keyword(s):  
Electronic Structure ◽  
Spatial Distribution ◽  
Surface Chemistry ◽  
Scanning Tunneling Microscopy ◽  
Epitaxial Growth ◽  
Atomic Resolution ◽  
Scanning Tunneling ◽  
Tunneling Microscopy

ABSTRACTWe apply scanning tunneling microscopy (STM) and spectroscopy (STS) to study the reaction of NH3 with Si(111)-(7×7), and the epitaxial growth of CaF2 on Si(11). By a combination of topographs and atom-resolved spectra we can follow the spatial distribution of the reaction and changes in electronic structure with atomic resolution. We find that there are strong site-selectivities for the NH3 reaction on the 7×7 surface. We also observe the initial stages of the CaF2 deposition and even are able to image insulating multi-layer CaF2 films.

Electronic Superstructures Observed by Scanning Tunneling Microscopy on Graphene Sheet in Vicinity of Nano-Defects of Ir(111) Substrate

2004 ◽  
Vol 19 (4) ◽  
pp. 1058-1061 ◽  
Author(s):  
Z. Waqar ◽  
I.V. Makarenko ◽  
A.N. Titkov ◽  
N.R. Gall ◽  
E.V. Rutkov ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Graphene Sheet ◽  
Surface Reconstruction ◽  
Graphene Layer ◽  
Scanning Tunneling ◽  
Real Surface ◽  
Two Dimensional ◽  
Tunneling Microscopy ◽  
Electronic Nature ◽  
Defect Sites

Two-dimensional electronic and atomic superstructures (SS) on monolayer graphite (graphene) grown on a clean Ir(111) surface were observed near substrate nano-defect sites by scanning tunneling microscopy. These SS were found rotated 30° with respect to the undistorted areas (away from defects sites) of the graphene layer with a periodicity of and a(a = 2.46 Å)decay over a distance of few nanometers away from the defects. The observed SS were not due to real surface reconstruction, rather they just had an electronic nature.

Scanning tunneling microscopy assisted oxide surface etching

1991 ◽  
Vol 69 (3) ◽  
pp. 1707-1711 ◽  
Author(s):  
D. Saulys ◽  
G. Rudd ◽  
E. Garfunkel
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Scanning Tunneling ◽  
Oxide Surface ◽  
Tunneling Microscopy ◽  
Surface Etching

Intrinsic Point Defects on a TiO2(110) Surface and Their Reaction with Oxygen: A Scanning Tunneling Microscopy Study

1997 ◽  
Vol 474 ◽  
Author(s):  
Markus Kuhn ◽  
J. F. Anderson ◽  
Jeremy Lehman ◽  
Talib Mahmoud ◽  
Ulrike Diebold
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Molecular Oxygen ◽  
Point Defects ◽  
Healing Process ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Defect Sites

ABSTRACTThe interaction of molecular oxygen, at room temperature, with a reduced TiO2(110) surface has been studied in situ by scanning tunneling microscopy (STM). Oxygen vacancies (point defects) were created on a clean TiO2(110) surface by annealing in ultra-high vacuum and successfully imaged on the atomic scale. These point defect sites were stable under ultrahigh vacuum conditions. During exposure to molecular oxygen, new point defects appear at different locations on the surface although their overall number is reduced. A mechanism for this dynamic healing process is proposed.

Direct visualization of the N impurity state in dilute GaNAs using scanning tunneling microscopy

Nanoscale ◽  
2015 ◽  
Vol 7 (40) ◽  
pp. 16773-16780 ◽  
Author(s):  
Nobuyuki Ishida ◽  
Masafumi Jo ◽  
Takaaki Mano ◽  
Yoshiki Sakuma ◽  
Takeshi Noda ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Scanning Tunneling Microscopy ◽  
Electronic Properties ◽  
Impurity State ◽  
Scanning Tunneling ◽  
Direct Visualization ◽  
Tunneling Microscopy ◽  
Impurity States

We report characterization of the spatial distribution and electronic properties of N impurity states in dilute GaNAs using scanning tunneling microscopy and spectroscopy.

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

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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