ISSN:1059-910X    

DOI:10.1002/jemt.1070200402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractDetails of the technique of reflection electron microscopy (REM) are described. Step by step instruction is given on how to do it on an ordinary electron microscope. Also given are some specimen preparation techniques and strategy of REM investigation.

ISSN:1059-910X    

DOI:10.1002/jemt.1070200403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractReflection electron microscope studies of surface dynamic processes are reviewed and illustrated with recent new observations. They include: surface electromigration and current dependent structures of Si surfaces; surface etching by oxidation of Si surface; and growth of two dimensional alloyed adsorbate by co‐deposition of metals on Si surface. The observations revealed details of the surface dynamic processes, which are difficult to obtain with other surface analysis technique

ISSN:1059-910X    

DOI:10.1002/jemt.1070200404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThe construction and performance of an ultrahigh vacuum reflection electron microscope (UHV REM) on the base of a transmission electron microscope with top entry stage are described. Some results of in situ study of structural transformations on clean silicon surfaces during sublimation, surface phase transitions, and initial stages of epitaxial growth are shown.

ISSN:1059-910X    

DOI:10.1002/jemt.1070200405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractIn this paper we report the effect of noble gas ions bombardment on the degradation of atomically flat Si(111) surfaces at room and high (400°C—600°C) temperatures. Reflection high energy electron diffraction (RHEED) and reflection electron microscopy (REM) have been used to characterize the topography and structure of the as‐implanted and post annealed surface layers. It is shown that the fading of the specularly reflected beam is not directly related to the amorphization of the surface. This experimental study has also evidenced the difficulties one meets to regrow a defect‐free material after amorphization by noble gas bombardment. For high temperature for which the amorphization is not possible, the surface loses its stepped structure and turns into a monocrystalline but atomically rough surface. This roughness is a function of substrate temp

ISSN:1059-910X    

DOI:10.1002/jemt.1070200406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractBloch wave equations for the multiple beam cases in reflection high energy electron diffraction (RHEED) are derived from the integral equation by forward‐ and back‐scattering Green function operators. A linearization is achieved through separation in a forward‐ and a back‐scattering component for each beam. This leads to a set of fundamental equations similar to the transmission case, but with a non‐Hermitian matrix, and the beams may be entered as either forward‐, back‐scattered, or both. The number of beams needed to be included in RHEED calculations is thus reduced, and so are the computing time and computer space required. The systematic row case, corresponding to reflections from planes parallel to the crystal surface, is treated in detail and illustrated by calculations of dispersion surfaces and rocking curves for Au(001). Symmetry relations for the systematic row and between reciprocal rows are discussed an

ISSN:1059-910X    

DOI:10.1002/jemt.1070200407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractHigh energy electron reflection (HEER) is an important technique in surface science and uses the information carried by high energy electrons reflected from surfaces to study surface structures and surface electronic states. With the development of reflection high energy electron diffraction (RHEED), high energy electron microscopy (REM), and high energy electron energy loss spectroscopy (EEL) in surface science, the usefulness of HEER has been widely recognized and demonstrated. However, a stationary dynamical solution for an arbitrary surface for HEER has not been obtained yet.In this paper, some developments in understanding the dynamical theory of HEER, particularly in recent years, are reviewed:1The introduction of the concept of current flow for a semi‐infinite crystal model has removed the confusion around the wave points in the “band gap”.2The consistency between the Bloch wave and multislice in the Bragg case has verified the validity of the argument of current flow and led to the emergence of the BMCR method (Bloch wave + Multislice Combined for Reflection).3The failure of the Bloch Wave‐Only solution (the BWO solution) on Au (110) surfaces in the Bragg case revealed by the BMCR method implies that previous BWO calculations in the Bragg case might be at fault.4The 2‐D dependence of the electron wave fields and Picard iteration‐like character of multislice calculation in the Bragg case has led to the emergence of an Edge Patching method in Multislice‐mode‐Only (the EPMO method). The new method yields an infinitely convergent stationary dynamical solution for an ar

ISSN:1059-910X    

DOI:10.1002/jemt.1070200408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractA review is given on the techniques and applications of high‐energy reflection electron energy‐loss spectroscopy (REELS) and reflection electron microscopy (REM) for surface studies in scanning transmission electron microscopes (STEM) and conventional transmission electron microscopes (TEM). A diffraction method is introduced to identify a surface orientation in the geometry of REM. The surface dielectric response theory is presented and applied for studying α‐alumina surfaces. Domains of the α‐alumina (012) surface initially terminated with oxygen can be reduced by an intense electron beam to produce Al metal; the resistance to beam damage of surface domains initially terminated with Al+3ions is attributed to the screening effect of adsorbed oxygen. Surface energy‐loss near‐edge structure (ELNES), extended energy‐loss fine structure (EXELFS), and microanalysis using REELS are illustrated based on the studies of TiO2and MgO. Effects of surface resonances (or channeling) on the REELS signal‐to‐background ratio are described. The REELS detection of a monolayer of oxygen adsorption on diamond (111) surfaces is reported.It is shown that phase contrast REM image content can be significantly increased with the use of a field emission gun (FEG). Phase contrast effects close to the core of a screw dislocation are discussed and the associated Fresnel fringes around a surface step are observed. Finally, an in situ REM experiment is described for studying atomic desorption and diffusion processes on α‐alumina surfaces at tempera

ISSN:1059-910X    

DOI:10.1002/jemt.1070200409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractAtomic steps on (111) and (100) crystal surfaces of Pt were observed using a commercial scanning electron microscope (SEM) in secondary electron mode. By comparing the SEM images and those by reflection electron microscopy (REM), the observed contrast was confirmed to be that from atomic steps on crystal surfaces. The contrast mechanism is briefly discussed. One application of this imaging technique is also shown.

ISSN:1059-910X    

DOI:10.1002/jemt.1070200410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThe double line contrast of a single‐atom height step observed in surface imaging for a single crystal in reflection electron microscopy is studied under a variety of experimental conditions. It is suggested that this abnormal contrast is directly associated with the dynamical electron diffraction process. The behavior of the double line contrast is closely related to the order of the Bragg reflected beam, and can be observed mostly under one of the two commonly cited resonance conditions. This phenomenon clearly reveals the differences in the surface imaging for various resonance condition

ISSN:1059-910X    

DOI:10.1002/jemt.1070200411

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY