Structural Characterization of Thin Metal Overlayers by X-ray Photoelectron and Auger-Electron Forward Scattering

1986 ◽  
Vol 83 ◽  
Author(s):  
W. F. Egelhoff
Keyword(s):  
Ultrathin Films ◽  
Surface Segregation ◽  
Metal Films ◽  
Epitaxial Films ◽  
Forward Scattering ◽  
Crystalline Lattice ◽  
Auger Electrons ◽  
X Ray ◽  
Metal Overlayers

ABSTRACTForward scattering of XPS and Auger electrons by atoms in a crystalline lattice produce beams of enhanced intensity radiating out from the surface at angles corresponding to the internuclear axes present in the top few atomic layers. This effect has been applied to analyze the mechanism of surface segregation in ultrathin metal films, to analyze the interdiffusion at the interfaces of ultrathin films, and to assess the effects of substrate contamination on the growth of epitaxial films. The systems studied in this work are Cu, Ni, and Co on Ni(100), however the purpose of this work is not to investigate these particular systems but to use them to illustrate the capabilities of forward scattering.

Structural and Magnetic Characterization of Rare Earth and Transition Metal Films Grown on Epitaxial Buffer Films on Semiconductor

1989 ◽  
Vol 151 ◽  
Author(s):  
R. F. C. Farrow ◽  
S. S. P. Parkin ◽  
V. S. Speriosu ◽  
A. Bezinge ◽  
A. P. Segmuller
Keyword(s):  
Rare Earth ◽  
Structural Characteristics ◽  
Metal Films ◽  
Epitaxial Films ◽  
Coherency Strain ◽  
Magnetic Data ◽  
Bulk Crystals ◽  
Structural Effects ◽  
X Ray

ABSTRACTStructural and magnetic data are presented and discussed for epitaxial films of rare earth metals ( Dy, Ho, Er) on LaF3 films on the GaAs(TTT) surface and Fe on Ag films on the GaAs(001) surface. Both systems exhibit unusual structural characteristics which influence the magnetic properties of the metal films. In the case of rare earth epitaxy on LaF3 we present evidence for epitaxy across an incommensurate or discommensurate interface. Coherency strain is not transmitted into the metal which behaves much like bulk crystals of the rare earths. In the case of Fe films , tilted epitaxy and long-range coherency strain are confirmed by X-ray diffractometry. Methods of controlling some of these structural effects by modifying the epitaxial structures are presented.

scholarly journals Montecarlo Simulation and HAXPES Analysis of Organosilane Segregation in Titania Xerogel Films; Towards a Generic Surface Chemofunctionalization Process

Surfaces ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 352-365
Author(s):  
Javier Mateo Moreno ◽  
Rodrigo Calvo Membibre ◽  
Sergio Pinilla Yanguas ◽  
Juan Rubio Zuazo ◽  
Miguel Manso Siván
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Segregation ◽  
Titanium Isopropoxide ◽  
Condensation Process ◽  
X Ray ◽  
Depth Profiles ◽  
Partial Charges ◽  
Xerogel Films ◽  
Non Destructive

The formation of xerogels implies a sequence of hydrolysis and condensation reactions, which are intricate to analyze in heteromolecular sols. We analyze by probabilistic Montecarlo methods the development of hybrid organosilane–titania xerogels and illustrate how partial charges of the reacting molecules can help estimating relative probabilities for the condensation of the molecules. Since the condensation rate of Ti alkoxides is much higher than the corresponding rate of Si alkoxides (especially if bearing a non-hydrolizable group), by imposing a fast condensation process in agreement with low pH kinetics, the process leads to a surface segregation of the organosilane. The simulation results are compared with results of characterization of thin condensates of two different organosilanes within a titanium–isopropoxide matrix. Non-destructive in-depth profiles were obtained by hard x-ray photoelectron spectroscopy, which can resolve through estimation of Si and specific moieties of the organosilane molecules the progress of the condensation. These results are relevant for the generalization of chemo-functionalization processes by kinetic demixing of organosilanes, which have myriad applications in biomedicine and biotechnology.

Characterization of (4,4)- and (5,3)-Type Stacking-Faults in 4deg.-Off 4H-SiC Epitaxial Wafers by Synchrotron X-Ray Topography and by Photo-Luminescence Spectroscopy

2013 ◽  
Vol 740-742 ◽  
pp. 585-588 ◽  
Author(s):  
T. Yamashita ◽  
H. Matsuhata ◽  
Y. Miyasaka ◽  
M. Odawara ◽  
K. Momose ◽  
...  
Keyword(s):  
Strain Field ◽  
Room Temperature ◽  
Stacking Faults ◽  
Photo Luminescence ◽  
Epitaxial Films ◽  
Luminescence Spectroscopy ◽  
X Ray ◽  
Different Types

Experimentally,the grazing-incident X-ray topography at different diffraction conditions, and room temperature photo-luminescence spectroscopy, various different types of stacking-faults in epitaxial films on 4-degrees-off 4H-SiC wafers were identified precisely without wafer cutting. Their types and the numbers were investigated statistically. It became clear that (4,4) type stacking-faults were the most common ones and two different types were identified. Still 34% of the stacking-faults were unknown types in the present investigation.Several different kinds of stacking-faults formed on the surface of 4-degrees-off 4H-SiC epitaxial wafers were investigated. Their types could be identified and type distribution in a wafer could be obtained using X-ray topography and room temperature Photo-Luminescence without wafer cutting. Type determination of 8H(4,4)- stacking fault ; with or without strain field, could also be decideddemonstrated using this method.

Composite Films of Copper / Boron Nitride and Nickel / Boron Nitride

1996 ◽  
Vol 451 ◽  
Author(s):  
Maria Hepel ◽  
Tania Tannatoli ◽  
Christopher Baxter ◽  
Richard Stephenson
Keyword(s):  
Boron Nitride ◽  
Potential Temperature ◽  
Composite Films ◽  
Pure Metal ◽  
Deposition Potential ◽  
Metal Films ◽  
Solution Temperature ◽  
X Ray ◽  
Steel Substrates

ABSTRACTThe formation and characterization of composite films of copper/boron nitride (Cu/BN) and nickel/boron nitride (Ni/BN) are described. Composite Cu/BN and Ni/BN films were synthesized by a metal electrodeposition from suspensions of boron nitride particles on carbon steel substrates. The effects of concentration of boron nitride in the solution, temperature, potential and various additives on the morphology of composite films have been investigated. The morphology of these films was examined using Scanning Electron Microscopy. The elemental analysis for boron, nitrogen, copper and nickel was performed using Energy Dispersive X-ray Spectroscopy (EDS), and a Microprobe X-ray Analyzer. The Vickers hardness of Cu/BN and Ni/BN films prepared under different conditions was also investigated. It has been found that the composite Cu/BN and Ni/BN films have an increased microhardness as compared to the respective pure metal films. The effects of deposition potential, temperature, concentration of BN and presence of various additives on the microhardness of Cu/BN and Ni/BN films have been investigated.

Change Of SI(111) Surface Reconstruction Under Noble Metal Films

1991 ◽  
Vol 237 ◽  
Author(s):  
Hawoong Hong ◽  
Richard Aburano ◽  
D.-S. Lin ◽  
T.-C. Chiang ◽  
Haydn Chen ◽  
...  
Keyword(s):  
Noble Metal ◽  
Room Temperature ◽  
Grazing Angle ◽  
Interface Structure ◽  
Metal Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Au Film ◽  
Metal Overlayers ◽  
Interface Structures

ABSTRACTInterface structures between Si(111) and thick noble metal overlayers are studied by grazing-angle-incidence x-ray diffraction and crystal truncation rods. The 7×7 reconstruction is only preserved under a Ag film deposited at room temperature. This capped 7×7 structure changed to a 1×1 structure upon annealing over 250°C. A thick overlayer of room temperature deposited Au film destroyed the 7×7 reconstruction and changed the interface structure to 1×1. Our results are compared to a thick Cu/Si(111) interface structure1.

Surface Characterization of Clean Gd5Ge4(010)

2012 ◽  
Vol 1517 ◽  
Author(s):  
Chad D. Yuen ◽  
Gordon J. Miller ◽  
Patricia A. Thiel
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Photoelectron Spectroscopy ◽  
Surface Characterization ◽  
Surface Segregation ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
X Ray ◽  
Show Evidence ◽  
Bulk Structure

AbstractBased on X-ray photoelectron spectroscopy, Gd5Ge4(010) does not show evidence of surface segregation. Scanning tunneling microscopy reveals two types of terraces which alternate laterally on the surface. From the step heights, these two surface terminations are assigned as dense, Gd-pure layers in the bulk structure. There is evidence of reconstruction on one type of terrace.

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