Reflection Electron Microscopy (REM) of Surface Steps & Dislocations on GaP(110) & GaAs(110)

1982 ◽  
Vol 40 ◽  
pp. 450-451
Author(s):  
Tung Hsu ◽  
Sumio Iijima
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Heating Stage ◽  
Surface Steps ◽  
Reflection Electron Microscopy ◽  
Electron Microscopes ◽  
High Vacuum Environment

Reflection electron microscopy (REM) in ultra high vacuum environment with heating stage has been reported by Osakabe, et al. In this paper, we present our results in REM imaging of single steps and dislocations using commercial electron microscopes (JEM-100B and Philips-400T) under ordinary pressure (10-7 torr) and room temperature.

Reflection Electron Microscopy and Diffraction from Crystal Surfaces

1983 ◽  
Vol 31 ◽  
Author(s):  
J.M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Surface Structure ◽  
Crystal Surfaces ◽  
Local Composition ◽  
Surface Steps ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Reflection Electron Microscopy ◽  
Electron Microscopes ◽  
Geometric Effects

ABSTRACTThe recent revival of techniques for the imaging of crystal surfaces, using electrons forward-scattered in the RHEED mode and employing modern electron microscopes, has lead to the introduction of valuable new methods for the study of surface structure. Either fixed beam or scanning transmission electron microscopy (STEM) instruments may be used and in each case a lateral resolution of 10Å or better is possible. Simple theoretical treatments suggest that the contrast from surface steps may be attributed to a combination of phase-contrast, diffraction contrast and geometric effects. With a STEM instrument the image information can be combined with information on the local composition and crystal structure by use of microanalysis and microdiffraction techniques. Examples of applications include studies of the surface structure of metals, semiconductors and oxides, and the surface reactions.

Scanning Reflection Electron Microscopy of 2x1 Domain Structure of Si(111) Surface

1985 ◽  
Vol 43 ◽  
pp. 264-265
Author(s):  
H.-J. Ou
Keyword(s):  
Electron Microscopy ◽  
Electron Diffraction ◽  
Spatial Resolution ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Intermediate Energies ◽  
Good Spatial Resolution ◽  
Probe Size ◽  
Reflection Electron Microscopy ◽  
Better Than

Studies of the surface structure of silicon with good spatial resolution made recently by reflection electron microscopy, (REM) have complemented and greatly extended the earlier studies, made by LEED and other methods, of the formation of surface reconstruction superstructures such a the Si(111) 7x7. These studies have not included the 2x1 superstructure on (111) surfaces formed by cleaving Si crystals in ultra-high vacuum. We have now investigated the form of the domains of this 2x1 structure by use of a reconstructed REMEDIE system 2.3 (for Reflection Electron Microscopy and Electron Diffraction at Intermediate Energies, 1-20keV). This system has shown a spatial resolution of better than 100Å although resolutions of about 300Å may be more common in practise because of the limitations due to probe size, vibration and signal noise.

In-Situ Transmission Electron Microscopy of the Etching of Silicon (111) Surfaces by Oxygen

1991 ◽  
Vol 238 ◽  
Author(s):  
J. M. Gibson ◽  
F. M. Ross
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Oxide Layer ◽  
Transmission Electron Microscope ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Surface Steps ◽  
Transmission Electron

ABSTRACTSilicon (111) surfaces have been etched in-situ in a ultra-high vacuum transmission electron microscope. Surface steps are observed to flow during etching, so that Si atoms are removed only from steps. This is in contrast to the behavior during the formation of an oxide layer reported previously. The nucleation of steps and their interaction with surface impurities is described.

UHV Electron Microscopy study of in situ annealed (100) surfaces of MgO

1991 ◽  
Vol 49 ◽  
pp. 624-625
Author(s):  
M. Gajdardziska-Josifovska ◽  
M. R. McCartney ◽  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Surface Characterization ◽  
High Vacuum ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Ultra High Vacuum ◽  
Frequent Use ◽  
Reflection Electron Microscopy ◽  
Catalyst Systems

The (100) surface of magnesium oxide is of considerable interest because of its frequent use as substrate for epitaxial growth of metal films, high Tc superconductors and model catalyst systems. A large number of surface characterization techniques have been used to determine the atomic structure of the cleaved (100) surface. Clean surfaces have been produced either by cleaving MgO crystals in-situ under ultra-high vacuum (UHV) conditions, or more frequently, by cleaving in air and subsequent annealing in UHV. A wide variety of annealing temperatures and times have been used by different researchers, the upper limit on the temperature being set at ≈900°C to avoid segregation of Ca to the surface. Calcium is the main impurity in even the purest MgO crystals and a few studies have dealt with the structure of the Ca-rich (100) surface of MgO. All of the existing studies have used diffraction and spectroscopy techniques without imaging of the surface. It is the purpose of this work to study the topography of the UHV-annealed (100) surface by reflection electron microscopy (REM).

A New Method For Calibrating Focusing Steps Of Electron Microscopes

1985 ◽  
Vol 43 ◽  
pp. 68-69
Author(s):  
Tung Hsu
Keyword(s):  
Electron Microscopy ◽  
Dark Field ◽  
New Method ◽  
Depth Of Field ◽  
Objective Lens ◽  
Focus Position ◽  
Bright Field ◽  
Surface Steps ◽  
Reflection Electron Microscopy ◽  
Electron Microscopes

Focusing steps of an electron microscope, i.e., the change of focus, Δf, corresponding to one click on any one of the focus dials must be calibrated. Two methods have been used; measuring the distance between bright field and dark field images of small crystalline particles and measuring the diameters of optical diffractograms obtained from the image of an amorphous specimen.A new method utilizing the large depth of field in reflection electron microscopy (REM) provides a direct means of measuring the focusing steps on the micrograph. The in focus area in an REM image can be recognized as the “least grainy” part or the minimum contrast of images of steps. Using surface steps, particles, or other features as References, the shift of this in focus position due to the variation of objective lens current can be readily measured on the micrograph. This distance is then converted to f by taking account of magnification (calibrated) and the foreshortening factor (calculated from the diffraction pattern).

Construction Of UHV-REM-PEEM for Surface Studies

1990 ◽  
Vol 48 (1) ◽  
pp. 350-351
Author(s):  
Y. Kondo ◽  
K. Yagi ◽  
K. Kobayashi ◽  
H. Kobayashi ◽  
Y. Yanaka
Keyword(s):  
Electron Microscopy ◽  
Electronic Structure ◽  
High Vacuum ◽  
Scanning Tunneling Spectroscopy ◽  
Ultra High Vacuum ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Surface Electronic Structure ◽  
Electron Microscopes

Recent development of ultra-high vacuum electron microscopy (UHV-EM) is very rapid. This is due to the fact that it can be applied to variety of surface science fields.There are various types of surface imaging in UHV condition; low energy electron microscopy (LEEM) [1], transmission (TEM) and reflection electron microscopy (REM) [2] using conventional transmission electron microscopes (CTEM) (including scanning TEM and REM)), scanning electron microscopy, photoemission electron microscopy (PEEM) [3] and scanning tunneling microscopy (STM including related techniques such as scanning tunneling spectroscopy (STS), atom force microscopy and magnetic force microscopy)[4]. These methods can be classified roughly into two; in one group image contrast is mainly determined by surface atomic structure and in the other it is determined by surface electronic structure. Information obtained by two groups of surface microscopy is complementary with each other. A combination of the two methods may give images of surface crystallography and surface electronic structure. STM-STS[4] and LEEM-PEEM [3] so far developed are typical examples.In the present work a combination of REM(TEM) and PEEM (Fig. 1) was planned with use of a UHV CTEM. Several new designs were made for the new microscope.

Reflection electron microscopy

1987 ◽  
Vol 20 (3) ◽  
pp. 147-160 ◽  
Author(s):  
K. Yagi
Keyword(s):  
Electron Microscopy ◽  
Imaging Techniques ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Surface Structures ◽  
Ion Sputtering ◽  
Adsorption Processes ◽  
Reflection Electron Microscopy ◽  
Reconstructed Surface ◽  
Surface Dynamic

Reflection electron microscopy (REM) in ultra-high vacuum (UHV) conditions is reviewed. UHV-REM can characterize surface structures of monolayer levels such as steps, domains of reconstructed surface structures and their boundaries and these capabilities are used to observe surface dynamic processes such as phase transitions of reconstructed surface structures and adsorbate structures and adsorption processes, oxidations, sublimations and ion-sputtering and annealing. The method is compared with other surface-imaging techniques.

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