RESONANCE SCATTERING OF HIGH ENERGY ELECTRONS BY A CRYSTAL SURFACE

1996 ◽  
Vol 10 (02) ◽  
pp. 133-168 ◽  
Author(s):  
S.L. DUDAREV ◽  
M.J. WHELAN
Keyword(s):  
Crystal Surface ◽  
Theoretical Models ◽  
Resonance Scattering ◽  
High Energy ◽  
Crystal Surfaces ◽  
Molecular Beam Epitaxial ◽  
Semiconductor Crystals ◽  
High Energy Electrons ◽  
Reflection Electron Microscopy ◽  
Molecular Beam Epitaxial Growth

In this review we summarize the results of recent experimental and theoretical studies of the phenomenon known as resonance scattering of high-energy electrons from crystal surfaces. Resonance scattering is responsible for the appearance of bright features observed in reflection high-energy electron diffraction (RHEED) patterns and has found numerous applications in reflection electron microscopy and in RHEED studies of dynamics of molecular beam epitaxial growth of semiconductor crystals. The origin of the effect remained obscure for more than sixty years following the discovery of resonance scattering by Kikuchi and Nakagawa in 1933. Below we review theoretical models of the phenomenon which have been developed recently and which have provided the basis for understanding of the mechanism of resonance scattering. We conclude the review with a list of presently unsolved problems which, as we hope, can stimulate future progress in the theory of RHEED.

The Origin of Resonance Phenomena in Reflection High-Energy Electron Diffraction

1995 ◽  
Vol 404 ◽  
Author(s):  
S. L. Dudarev ◽  
M. J. Whelan
Keyword(s):  
Electron Diffraction ◽  
Crystal Surface ◽  
Resonance Scattering ◽  
High Energy ◽  
Energy Electron ◽  
High Energy Electron ◽  
Theoretical Understanding ◽  
Molecular Beam Epitaxial ◽  
High Energy Electrons ◽  
Molecular Beam Epitaxial Growth

AbstractResonance scattering of high-energy electrons is responsible for the appearance of bright features observed in reflection high-energy electron diffraction (RHEED) patterns and has found numerous applications in reflection electron microscopy and in RHEED studies of dynamics of molecular beam epitaxial growth of semiconductor crystals. In this paper we report on recent developments in theoretical understanding of the processes leading to resonance reflection of high-energy electrons from a crystal surface.

Surface Characterization by Reflection Electron Microscopy (REM)

1984 ◽  
Vol 41 ◽  
Author(s):  
Tung Hsu ◽  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Surface Characterization ◽  
Crystal Surface ◽  
Stacking Faults ◽  
High Sensitivity ◽  
High Energy ◽  
Surface Layers ◽  
High Energy Electrons ◽  
Unique Method ◽  
Reflection Electron Microscopy

AbstractReflection electron microscopy (REM) utilizes the Bragg reflected high energy electrons to form the image of a crystal surface. Images of dislocations, atomic steps, reconstructions of surface layers of atoms and adatoms, stacking faults and twinning, superlattices, etc., have been successfully observed on a wide variety of specimens. Contrast is mainly due to diffraction and phase, which distiguished REM as a unique method for high spacial resolution and high sensitivity imaging of the surfaces of bulk specimens. REM can be effectively performed under UHV as well as under the moderate vacuum of an ordinary commercial electron microscope.

scholarly journals The effects of laser illumination and high energy electrons on molecular‐beam epitaxial growth of CdTe

1991 ◽  
Vol 69 (1) ◽  
pp. 268-272 ◽  
Author(s):  
Y. S. Wu ◽  
C. R. Becker ◽  
A. Waag ◽  
R. N. Bicknell‐Tassius ◽  
G. Landwehr
Keyword(s):  
Epitaxial Growth ◽  
Molecular Beam ◽  
High Energy ◽  
Laser Illumination ◽  
Molecular Beam Epitaxial ◽  
High Energy Electrons ◽  
Molecular Beam Epitaxial Growth

Experiments on REM and SREM using a Tem/Stem Microscope with a Configurable Angle-Resolving Detector

1990 ◽  
Vol 48 (1) ◽  
pp. 338-339
Author(s):  
H. Banzhof ◽  
I. Daberkow
Keyword(s):  
Electron Microscopy ◽  
Single Crystal ◽  
Crystal Surface ◽  
High Energy ◽  
Contrast Effects ◽  
Atomic Steps ◽  
Single Crystal Surfaces ◽  
Platinum Single Crystal ◽  
Reflection Electron Microscopy ◽  
Beam Reflection

A Philips EM 420 electron microscope equipped with a field emission gun and an external STEM unit was used to compare images of single crystal surfaces taken by conventional reflection electron microscopy (REM) and scanning reflection electron microscopy (SREM). In addition an angle-resolving detector system developed by Daberkow and Herrmann was used to record SREM images with the detector shape adjusted to different details of the convergent beam reflection high energy electron diffraction (CBRHEED) pattern.Platinum single crystal spheres with smooth facets, prepared by melting a thin Pt wire in an oxyhydrogen flame, served as objects. Fig. 1 gives a conventional REM image of a (111)Pt single crystal surface, while Fig. 2 shows a SREM record of the same area. Both images were taken with the (555) reflection near the azimuth. A comparison shows that the contrast effects of atomic steps are similar for both techniques, although the depth of focus of the SREM image is reduced as a result of the large illuminating aperture. But differences are observed at the lengthened images of small depressions and protrusions formed by atomic steps, which give a symmetrical contrast profile in the REM image, while an asymmetric black-white contrast is observed in the SREM micrograph. Furthermore the irregular structures which may be seen in the middle of Fig. 2 are not visible in the REM image, although it was taken after the SREM record.

Surface resonance scattering of high energy electrons

1994 ◽  
Vol 72 (7) ◽  
pp. 1032-1035 ◽  
Author(s):  
S. L. Dudarev ◽  
M. J. Whelan
Keyword(s):  
Resonance Scattering ◽  
High Energy ◽  
High Energy Electrons ◽  
Surface Resonance

Molecular Beam Epitaxial Growth of Nonpolar a-plane InN/ GaN Heterostructures

2012 ◽  
Vol 1396 ◽  
Author(s):  
Mohana K. Rajpalke ◽  
Thirumaleshwara N. Bhat ◽  
Basanta Roul ◽  
Mahesh Kumar ◽  
S. B. Krupanidhi
Keyword(s):  
Schottky Barrier ◽  
Molecular Beam ◽  
Schottky Barrier Height ◽  
High Energy ◽  
Scanning Electron Micrographs ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molecular Beam Epitaxial ◽  
Diffraction Patterns ◽  
Molecular Beam Epitaxial Growth

ABSTRACTNonpolar a-plane InN/GaN heterostructures were grown by plasma assisted molecular beam epitaxy. The growth of nonpolar a- plane InN / GaN heterostructures were confirmed by high resolution x-ray diffraction study. Reflection high energy electron diffraction patterns show the reasonably smooth surface of a-plane GaN and island-like growth for nonpolar a-plane InN film, which is further confirmed by scanning electron micrographs. An absorption edge in the optical spectra has the energy of 0.74 eV, showing blueshifts from the fundamental band gap of 0.7 eV. The rectifying behavior of the I-V curve indicates the existence of Schottky barrier at the InN and GaN interface. The Schottky barrier height (φb) and the ideality factor (η) for the InN/GaN heterostructures found to be 0.58 eV and 2.05 respectively.

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