Scanning Low-Energy Electron Diffraction Microscopy Combined with Scanning Tunnling Microscopy

1990 ◽  
Vol 48 (1) ◽  
pp. 302-303
Author(s):  
Takeo Ichinokawa
Keyword(s):  
Electron Diffraction ◽  
Electron Energy ◽  
High Vacuum ◽  
Low Energy ◽  
Energy Electron ◽  
Scanning Tunneling ◽  
Two Dimensional ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron ◽  
Auger Microscopy

A ultra-high vacuum scanning electron microscope (UHV-SEM) with a field emission gun (FEG) has been operated in an energy range of from 100 eV to 3 keV. A new technique of scanning low energy electron diffraction (LEED) microscopy has been added to the other techniques: scanning Auger microscopy (SAM), secondary electron microscopy, electron energy loss microscopy and the others available for the UHV-SEM. In addition to scanning LEED microscopy, a scanning tunneling microscope (STM) has been installed in the UHV-SEM-.The combination of STM with SEM covers a wide magnification range from 105 to 107 and is very effective for observation of surface structures with a high resolution of about 1 Å.A UHV-FEG-SEM is equipped in a chamber in which the vacuum is better than 2×10-10 Torr. A movable cylindrical mirror analyzer (CMA), a two dimensional detector of diffracted LEED beams, an ion gun and a deposition source are installed in this chamber. The concept of the scanning LEED microscope is comprised of two steps: (1) the formation of a selected area LEED pattern and (2) the generation of raster images with information contained in the diffraction pattern. In the present experiment, the LEED detector assembly shown in Fig.l has been used; it consists of two hemisherical grids, a two-stage channel-plate amplifier and a position-sensitive detector. The selection of one (or more) diffracted beam is performed electronically by a window using the two-dimensional analogue comparators. The intensity of a particular beam selected by the window modulates the brightness of the scanning image and a dark field image sensitive to the surface structure is formed. The experimental spatial resolutions of 150 Å and 500 Å have been attained at the primary electron energy 1 keV and 250 eV, respectively.

scholarly journals Growth of germanium on Au(111): formation of germanene or intermixing of Au and Ge atoms?

2017 ◽  
Vol 19 (28) ◽  
pp. 18580-18586 ◽  
Author(s):  
Esteban D. Cantero ◽  
Lara M. Solis ◽  
Yongfeng Tong ◽  
Javier D. Fuhr ◽  
María Luz Martiarena ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Scanning Tunneling Microscopy ◽  
High Vacuum ◽  
Low Energy ◽  
Energy Electron ◽  
Ultra High Vacuum ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron

We studied the growth of Ge layers on Au(111) under ultra-high vacuum conditions from the submonolayer regime up to a few layers with Scanning Tunneling Microscopy (STM), Direct Recoiling Spectroscopy (DRS) and Low Energy Electron Diffraction (LEED).

scholarly journals Lateral ordering of PTCDA on the clean and the oxygen pre-covered Cu(100) surface investigated by scanning tunneling microscopy and low energy electron diffraction

2014 ◽  
Vol 10 ◽  
pp. 2055-2064 ◽  
Author(s):  
Stefan Gärtner ◽  
Benjamin Fiedler ◽  
Oliver Bauer ◽  
Antonela Marele ◽  
Moritz M Sokolowski
Keyword(s):  
Electron Diffraction ◽  
Scanning Tunneling Microscopy ◽  
Low Energy ◽  
Energy Electron ◽  
Scanning Tunneling ◽  
Structure Model ◽  
Tunneling Microscopy ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron ◽  
Lattice Planes

We have investigated the adsorption of perylene-3,4,9,10-tetracarboxylic acid dianhydride (PTCDA) on the clean and on the oxygen pre-covered Cu(100) surface [referred to as (√2 × 2√2)R45° – 2O/Cu(100)] by scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). Our results confirm the (4√2 × 5√2)R45° superstructure of PTCDA/Cu(100) reported by A. Schmidt et al. [J. Phys. Chem. 1995, 99,11770–11779]. However, contrary to Schmidt et al., we have no indication for a dissociation of the PTCDA upon adsorption, and we propose a detailed structure model with two intact PTCDA molecules within the unit cell. Domains of high lateral order are obtained, if the deposition is performed at 400 K. For deposition at room temperature, a significant density of nucleation defects is found pointing to a strong interaction of PTCDA with Cu(100). Quite differently, after preadsorption of oxygen and formation of the (√2 × 2√2)R45° – 2O/Cu(100) superstructure on Cu(100), PTCDA forms an incommensurate monolayer with a structure that corresponds well to that of PTCDA bulk lattice planes.

Theory of Low-Energy Electron Diffraction

1967 ◽  
Vol 22 (3) ◽  
pp. 322-330 ◽  
Author(s):  
Kyozaburo Kambe
Keyword(s):  
Integral Equation ◽  
Electron Diffraction ◽  
Low Energy ◽  
Energy Electron ◽  
Two Dimensional ◽  
Band Theory ◽  
Low Energy Electron Diffraction ◽  
Diffracted Waves ◽  
Low Energy Electron ◽  
Cellular Method

A method for calculating the intensities of diffracted waves in low energy electron diffraction by crystals is proposed. The elastic multiple scattering is fully taken into account. The cellular method of KOHN and ROSTOKER in the band theory of metals is applied to the integral equation of the scattering by two dimensional lattices, particularly by monatomic layers. The solution is expanded in spherical harmonics on the surface of spheres, within which the atomic potential is assumed to be confined.

scholarly journals Surface study of the (100) and (010) faces of the quasicrystalapproximant Al4(Cr, Fe)

2009 ◽  
Vol 224 (1-2) ◽  
Author(s):  
Joseph Smerdon ◽  
Joseph Parle ◽  
Ronan McGrath ◽  
Birgitta Bauer ◽  
Peter Gille
Keyword(s):  
Electron Diffraction ◽  
Scanning Tunneling Microscopy ◽  
Low Energy ◽  
Energy Electron ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Low Energy Electron Diffraction ◽  
Surface Study ◽  
Low Energy Electron

AbstractLow-energy electron diffraction (LEED) and scanning tunneling microscopy (STM) results are used to study the pseudo-6-fold nature of the (100) surface of the orthorhombic quasicrystal approximant Al

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