Brownian Motion and Coarsening of Domain Boundaries on (7×7)-Si(111)

1995 ◽  
Vol 404 ◽  
Author(s):  
Pita Atala ◽  
R. J. Phaneuf ◽  
N. C. Barteltl ◽  
W. Swiech ◽  
E. Bauer
Keyword(s):  
Average Distance ◽  
Domain Boundary ◽  
Statistical Problem ◽  
Low Energy ◽  
One Dimension ◽  
Phase Domain ◽  
Time Motion ◽  
Domain Boundaries ◽  
Low Energy Electron ◽  
Energetic Interactions

AbstractWe have used low-energy electron microscopy to investigate the real-time motion of (7×7) out-of-phase domain boundaries in the (7×7) reconstruction on vicinal Si(111), just below the phase transition temperature. As a function of time, the domain boundaries wander and coalesce in one-dimension, parallel to the step edges. We have established that the motion is consistent with the statistical problem of a random walk in the presence of absorbing barriers and have measured the diffusion coefficient for domain boundary wandering. The average distance between domain boundaries becomes large as they coarsen, consequently energetic interactions are not significant in determining their arrangement on this surface.

Microdiffraction from out of Phase Domain Boundaries and Stacking Faults

1982 ◽  
Vol 40 ◽  
pp. 698-699
Author(s):  
J. Zhu ◽  
J.M. Cowley ◽  
H.Q. Ye
Keyword(s):  
Electron Beam ◽  
Source Function ◽  
Domain Boundary ◽  
Antiphase Domain ◽  
Step Function ◽  
Phase Object ◽  
Phase Domain ◽  
Domain Boundaries ◽  
The Fourier Transform ◽  
Coherent Source

It has been pointed out1 that any discontinuity at the edge of a crystal or within a crystal may give rise to spot splitting in microdiffraction patterns.The present work gives the basic theory for an antiphase domain boundary in Cu3Au and a twinning boundary in a f.c.c. crystal illuminated by a finite electron beam, which has a diameter of about 15Å. The treatment is based on the weak phase object approximation. These boundaries are planar faults. Multiplying a step function s(x) by the crystal potential expresses the discontinuity in the potential of the sample. When both sides of the boundary in the sample are illuminated by the finite coherent source and the boundary is parallel to the electron beam, the splitting of microdiffraction spots results from the convolution of the Fourier transform of the step function and the finite coherent source function.

ORDERED AND DISORDERED RIPPLING IN THE CoAl(110)-(1×1) SURFACE

1996 ◽  
Vol 03 (03) ◽  
pp. 1409-1415 ◽  
Author(s):  
V. BLUM ◽  
C. RATH ◽  
G.R. CASTRO ◽  
M. KOTTCKE ◽  
L. HAMMER ◽  
...  
Keyword(s):  
Average Distance ◽  
Low Energy ◽  
Chemical Order ◽  
Low Energy Electron Diffraction ◽  
R Factor ◽  
Preferential Sputtering ◽  
Topmost Layer ◽  
Low Energy Electron ◽  
The Ideal

A quantitative structural analysis of CoAl(110)-(1×1) by low energy electron diffraction shows that the topmost layer of the surface is rippled by an amplitude of 0.18 Å, with aluminum atoms pulled out of the surface and the average distance to the second layer only slightly expanded. In contrast to the perfect stoichiometry found for the top layer and the chemical order in the bulk, about 20% of the second layer Al atoms are substituted by Co. This is probably due to preferential sputtering during the course of sample preparation and incomplete subsequent reordering. A new version of Tensor LEED allows the detection of some disordered rippling induced by the substitutional disorder in this layer, with substitutional cobalt being 0.05 Å above the ideal aluminum position. The quality of the theory–experiment fit is mirrored by a Pendry R factor value of R=0.10.

Step and Domain Boundary Effect of Surface Reconstruction to Si(111)-√ 3×√3-Ag

2012 ◽  
Vol 554-556 ◽  
pp. 357-361
Author(s):  
Dong Mei Deng ◽  
Li Na Sun ◽  
Yu Rong Dai ◽  
Shi Xun Cao ◽  
Li Hua Bai ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Second Harmonic ◽  
Boundary Effect ◽  
Domain Boundary ◽  
Low Energy ◽  
Energy Electron ◽  
Harmonic Intensity ◽  
Low Energy Electron Diffraction ◽  
Significant Difference ◽  
Low Energy Electron

The influence of step and domain boundary on growth of Si(111)-√ 3×√3-Ag has been studied in situ using optical surface second-harmonic generation and low energy electron diffraction. The second harmonic intensity shows a difference of about 50% for Si(111) surfaces with different miscut angles and domain boundary densities, although no significant difference has been observed in low energy electron diffraction patterns, indicating a significant impediment to the growth of Si(111)-√ 3×√3-Ag by step and domain boundaries. Simulation results reveal a 90% coverage of Si(111)-√ 3×√3-Ag on the vicinal substrate with an miscut angle of 0.41o, consistent with the dynamics of Ag atoms on Si(111)-7×7 surface. The influence of two dimentional adatom gas on surface structure has also been discussed.

Performance Evaluation of a Novel Type of Low-Energy Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 354-355
Author(s):  
Bertholdand Senftinger ◽  
Helmut Liebl
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Field Strength ◽  
Numerical Aperture ◽  
Low Energy ◽  
Energy Electron ◽  
High Resolution Imaging ◽  
Lens System ◽  
Resolution Imaging ◽  
Low Energy Electron

During the last few years the investigation of clean and adsorbate-covered solid surfaces as well as thin-film growth and molecular dynamics have given rise to a constant demand for high-resolution imaging microscopy with reflected and diffracted low energy electrons as well as photo-electrons. A recent successful implementation of a UHV low-energy electron microscope by Bauer and Telieps encouraged us to construct such a low energy electron microscope (LEEM) for high-resolution imaging incorporating several novel design features, which is described more detailed elsewhere.The constraint of high field strength at the surface required to keep the aberrations caused by the accelerating field small and high UV photon intensity to get an improved signal-to-noise ratio for photoemission led to the design of a tetrode emission lens system capable of also focusing the UV light at the surface through an integrated Schwarzschild-type objective. Fig. 1 shows an axial section of the emission lens in the LEEM with sample (28) and part of the sample holder (29). The integrated mirror objective (50a, 50b) is used for visual in situ microscopic observation of the sample as well as for UV illumination. The electron optical components and the sample with accelerating field followed by an einzel lens form a tetrode system. In order to keep the field strength high, the sample is separated from the first element of the einzel lens by only 1.6 mm. With a numerical aperture of 0.5 for the Schwarzschild objective the orifice in the first element of the einzel lens has to be about 3.0 mm in diameter. Considering the much smaller distance to the sample one can expect intense distortions of the accelerating field in front of the sample. Because the achievable lateral resolution depends mainly on the quality of the first imaging step, careful investigation of the aberrations caused by the emission lens system had to be done in order to avoid sacrificing high lateral resolution for larger numerical aperture.

Low-Energy-Electron-Diffraction Structural Studies of (100) Cleavage Surfaces of In4Se3 Layered Crystals

2014 ◽  
Vol 59 (6) ◽  
pp. 612-621 ◽  
Author(s):  
P.V. Galiy ◽  
◽  
Ya.B. Losovyj ◽  
T.M. Nenchuk ◽  
I.R. Yarovets’ ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Low Energy ◽  
Energy Electron ◽  
Structural Studies ◽  
Low Energy Electron Diffraction ◽  
Layered Crystals ◽  
Low Energy Electron

scholarly journals Low-energy electron impact dissociative recombination and vibrational transitions of N2+

2021 ◽  
Vol 129 (5) ◽  
pp. 053303
Author(s):  
A. Abdoulanziz ◽  
C. Argentin ◽  
V. Laporta ◽  
K. Chakrabarti ◽  
A. Bultel ◽  
...  
Keyword(s):  
Electron Impact ◽  
Dissociative Recombination ◽  
Low Energy ◽  
Energy Electron ◽  
Low Energy Electron ◽  
Vibrational Transitions

A low stray light, high current, low energy electron source

1999 ◽  
Vol 70 (10) ◽  
pp. 3886-3888 ◽  
Author(s):  
M. Adelt ◽  
R. Körber ◽  
W. Drachsel ◽  
H.-J. Freund
Keyword(s):  
Electron Source ◽  
Low Energy ◽  
Energy Electron ◽  
Stray Light ◽  
High Current ◽  
Low Energy Electron
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