STRUCTURE AND THERMAL STABILITY OF THE SULFIDE OVERLAYERS ON CH3CSNH2-PASSIVATED GaAs(100) SURFACES

2001 ◽  
Vol 08 (01n02) ◽  
pp. 19-23 ◽  
Author(s):  
F. Q. XU ◽  
E. D. LU ◽  
H. B. PAN ◽  
C. K. XIE ◽  
P. S. XU ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Electron Spectroscopy ◽  
Photoemission Spectroscopy ◽  
Low Energy Electron Diffraction ◽  
Native Oxides ◽  
Sulfur Passivation ◽  
Different Temperatures ◽  
Low Energy Electron ◽  
Synchrotron Radiation Photoemission ◽  
Thermal Stability Of

Chemically sulfur passivation of GaAs(100) by thioacetamide ( CH 3 CSNH 2) has been studied using synchrotron radiation photoemission spectroscopy (SRPES), Auger electron spectroscopy (AES) and low energy electron diffraction (LEED). The measurement of SRPES and AES showed that the top layer of native oxides over GaAs(100) was removed and the sulfides of Ga and As were formed after the passivation process. The thermal stability and surface structure have also been studied by annealing the passivated samples at different temperatures. We found that the surface sulfides could be removed gradually; as a result, a clean, ordered and thus Fermi level unpinning surface was finally achieved. The surface restructures with GaAs(100)–S(2×1) and 4×1 LEED patterns were observed on annealing above 260°C and at 550°C respectively.

VALENCE ELECTRONIC STRUCTURE OF OXYGEN-MODIFIED α-Mo2C(0001) SURFACE: ANGLE-RESOLVED PHOTOEMISSION STUDY

2006 ◽  
Vol 13 (02n03) ◽  
pp. 185-190
Author(s):  
M. KATO ◽  
K. OZAWA ◽  
T. SATO ◽  
K. EDAMOTO
Keyword(s):  
Electron Spectroscopy ◽  
Oxygen Adsorption ◽  
Photoemission Spectroscopy ◽  
Metallic State ◽  
Low Energy Electron Diffraction ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Peak Intensity ◽  
Low Energy Electron ◽  
Photoemission Study ◽  
Surface Angle

Adsorption of oxygen on α- Mo 2 C (0001) is investigated with Auger electron spectroscopy (AES), low-energy electron diffraction (LEED) and angle-resolved photoemission spectroscopy (ARPES) utilizing synchrotron radiation. It is found that C KLL Auger peak intensity does not change during O 2 exposure, indicating that the depletion of C atoms does not proceed. It is deduced from ARPES and LEED results that adsorbed oxygen atoms from a well-ordered (1 × 1) lattice on the α- Mo 2 C (0001) surface. The ARPES study shows that oxygen adsorption induces a peculiar state around Fermi level (E F ). Off-normal-emission measurements prove that the state is a half-filled metallic state.

scholarly journals Transition from silicene monolayer to thin Si films on Ag(111): comparison between experimental data and Monte Carlo simulation

2018 ◽  
Vol 9 ◽  
pp. 48-56 ◽  
Author(s):  
Alberto Curcella ◽  
Romain Bernard ◽  
Yves Borensztein ◽  
Silvia Pandolfi ◽  
Geoffroy Prévot
Keyword(s):  
Electron Spectroscopy ◽  
Auger Electron ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Low Energy Electron Diffraction ◽  
Different Temperatures ◽  
Low Energy Electron ◽  
Simple Growth ◽  
Si Films ◽  
Good Agreement

Scanning tunneling microscopy (STM), Auger electron spectroscopy (AES) and low energy electron diffraction have been used to follow the growth of Si films on Ag(111) at various temperatures. Using a simple growth model, we have simulated the distribution of film thickness as a function of coverage during evaporation, for the different temperatures. In the temperature regime where multilayer silicene has been claimed to form (470–500 K), a good agreement is found with AES intensity variations and STM measurements within a Ag surfactant mediated growth, whereas a model with multilayer silicene growth fails to reproduce the AES measurements.

The research of CdZnTe (111)B surface with synchrotron radiation photoemission spectroscopy

2009 ◽  
Vol 24 (5) ◽  
pp. 1639-1641 ◽  
Author(s):  
Gangqiang Zha ◽  
Wanqi Jie ◽  
Tingting Tan ◽  
XuXu Bai ◽  
Li Fu ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Work Function ◽  
Photoemission Spectroscopy ◽  
Low Energy Electron Diffraction ◽  
Local Reconstruction ◽  
Atomic Structures ◽  
Low Energy Electron ◽  
Synchrotron Radiation Photoemission ◽  
The Ideal

The clean and ordered surfaces of CdZnTe (111)B grown by the Bridgman method were obtained by Ar ion bombardment and thermal annealing in situ in an ultrahigh vacuum. The surface atomic structures of CdZnTe (111)B after annealing at different temperature were observed by low-energy electron diffraction (LEED). The valence band and work function of CdZnTe (111)B surfaces were determined by synchrotron radiation photoemission spectroscopy. The order of CdZnTe (111)B after annealing at 350 °C will worsen, and the (111)B-(2 × 2) local reconstruction will be formed. The work function of CdZnTe (111)B after annealing at 350 °C is 0.8 eV higher than that of CdZnTe (111)B-(1 × 1), and the local reconstruction may be induced by Te adatoms on top of the ideal truncation.

Investigation of the structure and stability of the Pt/SiC(001) interface

1990 ◽  
Vol 5 (12) ◽  
pp. 2882-2893 ◽  
Author(s):  
V. M. Bermudez ◽  
R. Kaplan
Keyword(s):  
Electron Spectroscopy ◽  
Auger Electron ◽  
Low Energy ◽  
Auger Line ◽  
Detailed Model ◽  
Low Energy Electron Diffraction ◽  
Line Shapes ◽  
Oriented Polycrystalline ◽  
Low Energy Electron ◽  
Thermal Stability Of

Auger electron spectroscopy and low energy electron diffraction have been applied to the study of the structure and thermal stability of the Pt/β–SiC(001) interface. The morphology of the interface appears to be governed by the competition among surface diffusion, intermixing, and chemical reaction. An ultrathin Pt layer (8 Å thick) deposited on a substrate at low temperature is laterally uniform with some degree of intermixing across the interface. Brief anneals at 1000 °C result in aggregation of the Pt into islands interspersed with essentially bare SiC. Higher temperatures lead to reaction of the aggregated Pt to form Pt silicide and release free C. The reaction is signaled by characteristic changes in the Si LVV and C KLL Auger line shapes and by the appearance in LEED of a (2 ⊠ 2) pattern (believed to arise from ordered PtSi) and of diffraction rings from oriented polycrystalline graphite. Subsequent deposition of Si and annealing leads to regeneration of SiC by reaction with the free C. These results contrast with those for ultrathin Pt on Si(001) and on α-SiC(0001) which are dominated by the rapid indiffusion of Pt during annealing. A detailed model is presented for the growth and annealing dependence of the Pt/β–SiC(001) interface.

scholarly journals Improved thermal stability of SiCf/SiC ceramic matrix composites fabricated by PIP process

2021 ◽  
Vol 15 (2) ◽  
pp. 164-169
Author(s):  
Jian Gu ◽  
Sea-Hoon Lee ◽  
Daejong Kim ◽  
Hee-Soo Lee ◽  
Jun-Seop Kim
Keyword(s):  
Thermal Stability ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Matrix Composites ◽  
Sic Fiber ◽  
Sic Ceramic ◽  
Different Temperatures ◽  
Pre Treatment ◽  
Thermal Deterioration ◽  
Thermal Stability Of

Improvement of the thermal stability of continuous SiC fiber reinforced SiC ceramic matrix composites (SiCf/SiC CMC) by the pre-treatment of SiC fillers and the suppression of oxidation during polymer impregnation and pyrolysis (PIP) process were investigated. Dense SiCf/SiC CMCs were fabricated using the slurry infiltration and PIP process under a purified argon atmosphere. Structure and mechanical properties of the SiCf/SiC CMC heated at different temperatures were evaluated. The flexural strength of the SiCf/SiC CMC decreased only 15.3%after heating at 1400 ?C, which exhibited a clear improvement compared with the literature data (49.5% loss), where severe thermal deterioration of SiCf/SiC composite occurred at high temperatures by the crystallization and decomposition of the precursor-derived ceramic matrix. The thermal stability of the SiCf/SiC CMC fabricated by PIP process was improved by the pre-treatment of SiC fillers for removing oxides and the strict atmosphere control to prevent oxidation.

Surface Band Structure Studies of Si Rich Reconstructions on 4H-SiC(1-100)

2005 ◽  
Vol 483-485 ◽  
pp. 547-550 ◽  
Author(s):  
Konstantin V. Emtsev ◽  
Thomas Seyller ◽  
Lothar Ley ◽  
A. Tadich ◽  
L. Broekman ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Electron Diffraction ◽  
Photoelectron Spectroscopy ◽  
Low Energy ◽  
Ultraviolet Photoelectron Spectroscopy ◽  
Surface Band ◽  
X Ray ◽  
Low Energy Electron Diffraction ◽  
Different Temperatures ◽  
Low Energy Electron

We have investigated Si-rich reconstructions of 4H-SiC( 00 1 1 ) surfaces by means of low-energy electron diffraction (LEED), x-ray photoelectron spectroscopy (XPS), and angleresolved ultraviolet photoelectron spectroscopy (ARUPS). The reconstructions of 4H-SiC( 00 1 1 ) were prepared by annealing the sample at different temperatures in a flux of Si. Depending on the temperature different reconstructions were observed: c(2×2) at T=800°C, c(2×4) at T=840°C. Both reconstructions show strong similarities in the electronic structure.

Thermal Stability of Mechanical Properties of Copper after Equal-Channel Angular Pressing

2008 ◽  
Vol 584-586 ◽  
pp. 960-965 ◽  
Author(s):  
Tamara Kravchenko ◽  
Alexander Korshunov ◽  
Natalia Zhdanova ◽  
Lev Polyakov ◽  
Irina Kaganova
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tensile Strength ◽  
Chemical Composition ◽  
Yield Strength ◽  
Equal Channel Angular Pressing ◽  
Angular Pressing ◽  
Different Temperatures ◽  
Thermal Stability Of

Annealed oxygen-free and tough-pitch copper samples have been processed by equalchannel angular pressing (ECAP) by route BC. The samples included 8 x 8 mm section pieces and a 40 mm diameter bar. Thermal stability was assessed based on the changes in the standard mechanical properties (conventional yield strength, tensile strength, elongation, proportional elongation and contraction) after annealing at different temperatures for 1 hour. Thermal stability of the same grade of material has been found to be different for different batches and to depend on the structural conditions of deformed material. The zone of thermal stability for copper of the two grades of interest does not depend on the material’s chemical composition.

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