The Ten-Fold Surface of The Decagonal Al72Ni11Co17 Quasicrystal Studied by Leed, Spa-Leed, Aes and Stm.

2000 ◽  
Vol 643 ◽  
Author(s):  
Erik J. Cox ◽  
Julian Ledieu ◽  
RÓn'n Mcgrath ◽  
Renee D. Diehl ◽  
Cynthia J. Jenks ◽  
...  
Keyword(s):  
Annealing Time ◽  
Electron Spectroscopy ◽  
Annealing Temperature ◽  
Profile Analysis ◽  
Low Energy Electron Diffraction ◽  
Annealing Temperatures ◽  
Scanning Tunnelling ◽  
Tunnelling Microscopy ◽  
Low Energy Electron ◽  
Stm Images

AbstractThe ten-fold surface of the decagonal Al72Ni11Co17 (d-Al-Ni-Co) quasicrystal has been investigated using low energy electron diffraction (LEED), spot profile analysis LEED (SPA- LEED), Auger electron spectroscopy (AES) and scanning tunnelling microscopy (STM). This was done as a function of both annealing temperature and annealing time. The long-range order of the surface, as indicated by LEED, increases both as a function of annealing time and temperature. STM shows the surface to be rough and cluster-like at low annealing temperatures (≤725 K), whilst annealing to temperatures in excess of 725 K results in the formation of terraces. These terraces are small (≤ 100 Å width) at lower annealing temperatures and increase in size (100 Å ≤ x ≤ 500 Å) as the annealing temperature is increased (≥ 850 K). They are characterised by the presence of three-fold protrusions which align preferentially. STM images show single height steps as expected due to the periodicity of d-Al-Ni-Co in the z direction. To date it has not been possible to obtain atomic resolution, although this work is continuing.

Reactive Diffusion of Thin Si Deposits into Ni (111)

2012 ◽  
Vol 323-325 ◽  
pp. 421-426
Author(s):  
B. Lalmi ◽  
C. Girardeaux ◽  
Alain Portavoce ◽  
Bernard Aufray ◽  
Jean Bernardini
Keyword(s):  
Electron Spectroscopy ◽  
Room Temperature ◽  
Reactive Diffusion ◽  
Isothermal Kinetics ◽  
Low Energy Electron Diffraction ◽  
Scanning Tunnelling ◽  
Tunnelling Microscopy ◽  
Low Energy Electron ◽  
Stm Images ◽  
Dimensional Surface

Low energy electron diffraction (LEED), Auger electron spectroscopy (AES) and scanning tunnelling microscopy (STM) were used to study the reactive diffusion of one monolayer of silicon deposited at room temperature onto a Ni (111) substrate. We have done isochronal and isothermal kinetics by AES, and we observed in both cases a kinetics blockage on a plateau corresponding to around one third of a silicon monolayer. STM images and LEED patterns both recorded at room temperature just after annealing, reveal formation of an ordered hexagonal superstructure corresponding probably to a two-dimensional surface silicide.

Bismuth Overlayer Formation on GaAs(110)

1989 ◽  
Vol 159 ◽  
Author(s):  
S.-L. Chang ◽  
T. Guo ◽  
W.K. Ford ◽  
A. Bowler ◽  
E.S. Hood
Keyword(s):  
Electron Diffraction ◽  
Long Range ◽  
Annealing Temperature ◽  
Profile Analysis ◽  
Low Energy ◽  
Sixth Order ◽  
Full Width ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron ◽  
Long Range Ordering

ABSTRACTThe temperature and coverage dependent ordering of bismuth overlayers on GaAs(110) is examined using low energy electron diffraction (LEED). Sixth order electron diffraction profiles associated with overlayer ordering are observed at coverages of 0.7, 1.0, and 1.5 monolayers (ML) and for temperatures ranging from -110 C to 200 C. The full-width at half-maxima (FWHM) of the sixth-order spots are examined. Profile analysis reveals narrowing widths with increasing annealing temperature, indicating an improvement of the long-range ordering of the overlayers. Differences in inter- and intrachain ordering are observed, analyzed, and discussed.

EFFECT OF Cu DEPOSITION AND ANNEALING UPON A GaSe/Si(111) HETEROJUNCTION

1999 ◽  
Vol 06 (06) ◽  
pp. 1173-1178 ◽  
Author(s):  
B. ABIDRI ◽  
J.-P. LACHARME ◽  
M. GHAMNIA ◽  
C. A. SÉBENNE ◽  
M. EDDRIEF ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Low Energy ◽  
Layered Semiconductor ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron ◽  
Temperature Interaction

Single crystal substrates of GaSe, a layered semiconductor with a 2 eV band gap, were epitaxially grown by MBE onto a Si(111)(1×1)–H substrate, forming a perfectly abrupt heterojunction. Controlled amounts of Cu were sequentially deposited onto the clean passive surface of GaSe from a few tenths to several hundred monolayers (1 ML refers to the GaSe surface: 8 × 1014 at/cm 2). After given Cu depositions, the effect of UHV annealings at increasing temperatures was studied, until GaSe removal. The system was characterized as a function of either Cu deposit or annealing temperature using low energy electron diffraction, Auger electron spectroscopy and photoemission yield spectroscopy. The room temperature interaction starts as an apparent intercalation process until Cu islands begin to form, beyond about 50 ML. Upon annealings as low as 250°C, several ML of Cu disappear into the bulk of an apparently recovered GaSe, towards the GaSe/Si interface.

scholarly journals Probing the interplay between geometric and electronic structure in a two-dimensional K–TCNQ charge transfer network

2017 ◽  
Vol 204 ◽  
pp. 97-110 ◽  
Author(s):  
P. J. Blowey ◽  
L. A. Rochford ◽  
D. A. Duncan ◽  
D. A. Warr ◽  
T.-L. Lee ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Structural Information ◽  
Standing Waves ◽  
Low Energy ◽  
X Ray ◽  
Low Energy Electron Diffraction ◽  
Scanning Tunnelling ◽  
Tunnelling Microscopy ◽  
Low Energy Electron ◽  
Carbon Core

Scanning tunnelling microscopy (STM), low energy electron diffraction (LEED), ultraviolet and soft X-ray photoelectron spectroscopy (UPS and SXPS) have been used to characterise the formation of a coadsorption phase of TCNQ and K on Ag(111), while the normal incident X-ray standing waves (NIXSW) technique has been used to obtain quantitative structural information. STM and LEED show that an ordered incommensurate phase is formed in which the K atoms are surrounded by four TCNQ molecules in a ‘windmill’ motif, characteristic of other metal/TCNQ phases, in which the nominal TCNQ : K stoichiometry is 1 : 1. UPS and SXPS data indicate the TCNQ is in a negatively-charged state. NIXSW results show that the carbon core of the TCNQ is essentially planar at a height above the Ag(111) surface closely similar to that found without coadsorbed K. In the presence of TCNQ the height of the K ions above the surface is significantly larger than on clean Ag(111), and the ions occupy sites above ‘holes’ in the TCNQ network. NIXSW data also show that the N atoms in the molecules must occupy sites with at least two different heights above the surface, which can be reconciled by a tilt or twist of the TCNQ molecules, broadly similar to the geometry that occurs in bulk TCNQ/K crystals.

scholarly journals Investigation of single-domain Au silicide nanowires on Si(110) formed for Au coverages in the monolayer regime

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stephan Appelfeller
Keyword(s):  
Fermi Level ◽  
Surface Structure ◽  
Density Of States ◽  
The Self ◽  
Single Domain ◽  
Photoemission Spectroscopy ◽  
Annealing Temperatures ◽  
Self Organized ◽  
Scanning Tunnelling ◽  
Tunnelling Microscopy

AbstractThe self-organized formation of single domain Au silicide nanowires is observed on Si(110). These nanowires are analysed using scanning tunnelling microscopy (STM) and spectroscopy (STS) as well as photoemission spectroscopy (PES). Core-level PES is utilised to confirm the formation of Au silicide and establish its presence as the top most surface structure, i.e., the nanowires. The growth of the Au silicide nanowires and their dimensions are studied by STM. They form for Au coverages of about 1 monolayer and are characterized by widths of about 2 to 3 nm and heights below 1 nm while reaching lengths exceeding 500 nm when choosing appropriate annealing temperatures. Valence band PES and STS indicate a small but finite density of states at the Fermi level typical for compound metals.

Surface Structures of Phosphorus and Indium on Si(111)

1998 ◽  
Vol 05 (01) ◽  
pp. 69-76
Author(s):  
F. P. Netzer ◽  
L. Vitali ◽  
J. Kraft ◽  
M. G. Ramesy
Keyword(s):  
Elevated Temperature ◽  
Room Temperature ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Low Energy Electron Diffraction ◽  
Diffusion Limited ◽  
Lower Terrace ◽  
Surface Reconstructions ◽  
Low Energy Electron ◽  
Stm Images

The interaction of vapor phase P2 with the [Formula: see text] monolayer surface at room temperature and elevated temperature has been monitored by scanning tunneling microscopy (STM) and spectroscopy (STS) in conjunction with Auger electron spectroscopy and low-energy electron diffraction (LEED). The surface rection can be readily followed by STM because of the very different contrast of the reacted areas in the STM images. The reaction develops around overlayer defects at room temperature and appears to be diffusion-limited, whereas at 300°C the reaction is initiated at the step edges, from which the reaction front progresses onto the lower terrace areas. At elevated temperature several ordered surface reconstructions, showing different STS fingerprints, are detected on the P–In/Si(111) surfaces, which are associated tentatively with P- and Si-terminated structures and an ordered InP phase.

About the Electrical Activation of 1×1020 cm-3 Ion Implanted Al in 4H-SiC at Annealing Temperatures in the Range 1500 - 1950°C

2018 ◽  
Vol 924 ◽  
pp. 333-338 ◽  
Author(s):  
Roberta Nipoti ◽  
Alberto Carnera ◽  
Giovanni Alfieri ◽  
Lukas Kranz
Keyword(s):  
Activation Energy ◽  
Sheet Resistance ◽  
Annealing Time ◽  
Thermal Activation ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Thermal Activation Energy ◽  
Electrical Activation ◽  
Temperature Range ◽  
Annealing Temperatures

The electrical activation of 1×1020cm-3implanted Al in 4H-SiC has been studied in the temperature range 1500 - 1950 °C by the analysis of the sheet resistance of the Al implanted layers, as measured at room temperature. The minimum annealing time for reaching stationary electrical at fixed annealing temperature has been found. The samples with stationary electrical activation have been used to estimate the thermal activation energy for the electrical activation of the implanted Al.

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