Probes: Sources and Their Interactions with Matter

2021 ◽  
pp. 277-344
Author(s):  
Kannan M. Krishnan
Keyword(s):  
Aqueous Dispersion ◽  
High Energy ◽  
Electron Interaction ◽  
Rf Plasma ◽  
Ion Scattering ◽  
Mass Spectrometers ◽  
Atomic Displacements ◽  
Low Energy Ion Scattering ◽  
Core Electrons ◽  
Energy And Momentum

Probes are generated using laboratory sources, or in large user facilities. Photon sources include incandescence and plasma discharge lamps. Electron beams are generated using thermionic or field-emission sources. RF plasma sources generate ions that are accelerated and used for scattering experiments. Specimens should be probed first with light, as it causes the least damage. Electron interaction with matter causes beam broadening, atomic displacements, sputtering, or radiolysis leading to mass loss and local contamination. Neutrons are heavier than electrons, penetrate more deeply in materials, and require more sample for analysis. Protons (positive charge, heavier than electrons) go a longer way in the specimen without significant broadening. Ions in solids undergo kinematic collisions with conservation of energy and momentum; they also lose energy continuously as they propagate. In the back-scattering geometry, they form important methods of Rutherford backscattering spectroscopy (RBS) and low-energy ion scattering spectroscopy (LEISS). Medium energy ions generate secondary ions by sputtering that can be analyzed by mass spectrometers to determine specimen composition (SIMS). Alternatively, its composition is analyzed (ICP-MS), by creating an aqueous dispersion and converting it to a plasma. Finally, interaction of high-energy ions with core electrons can lead to inner shell ionization and characteristic X-ray emission (PIXE).

Multitechnique surface spectroscopic studies of plasma-modified polymers I: H2O/Ar plasma-modified polymethylmethacrylates

1987 ◽  
Vol 2 (1) ◽  
pp. 117-131 ◽  
Author(s):  
Thomas J. Hook ◽  
Joseph A. Gardella ◽  
Lawrence Salvati
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Polymer Surface ◽  
Spectroscopic Studies ◽  
Rf Plasma ◽  
Ion Scattering ◽  
Modified Polymers ◽  
Low Energy Ion Scattering ◽  
Structural Differences ◽  
Limited Depth

Results from x-ray photoelectron spectroscopy (XPS or ESCA), low-energy ion scattering spectrometry (LEIS or ISS); and Fourier transform infrared spectroscopy (FTIR) analyses are presented for unmodified and modified poly (methylmethacrylate) (PMMA) polymer films. Analysis of the unmodified PMMA polymers (isotactic, syndiotactic, and atactic) via ESCA, ISS, and FTIR, established the surface composition, bonding, and functionality before the modification was employed. An rf-plasma glow discharge created from an Ar/H2O gas mixture at different exposure times and power levels was used to treat the polymer surface. Subsequent ESCA, ISS, and FTIR analyses of these modified PMMA's show the effects of surface modification in terms of a model of structural differences, over a limited depth (50–100 Å). The composition and functionality changes of the resulting surfaces are discussed with respect to proposed mechanisms of the plasma reaction and differences in tacticity of the reactant. A two-step reaction mechanism involving reactive decarboxylation/reduction followed by H2O adsorption is proposed to understand the spectroscopic results.

GROWTH AND STRUCTURE OF hcp Ti FILMS ON Al(111) SURFACES

1999 ◽  
Vol 06 (05) ◽  
pp. 775-780 ◽  
Author(s):  
Y. W. KIM ◽  
G. A. WHITE ◽  
N. R. SHIVAPARAN ◽  
M. A. TETER ◽  
R. J. SMITH
Keyword(s):  
Photoelectron Spectroscopy ◽  
Film Growth ◽  
Three Dimensional ◽  
High Energy ◽  
Low Energy ◽  
Ion Scattering ◽  
Island Growth ◽  
X Ray ◽  
Low Energy Ion Scattering ◽  
Ti Films

The structure of thin Ti films grown on Al(111) surfaces at room temperature has been studied using high energy ion scattering/channeling (HEIS), X-ray photoelectron spectroscopy (XPS), low energy ion scattering (LEIS), low energy electron diffraction (LEED) and X-ray photoelectron diffraction (XPD). Our results show that Ti grows in the SK mode on the Al(111) surface. Ti atoms form a two-dimensional overlayer up to a deposition of about 2 ML Ti, followed by three-dimensional island growth with additional Ti deposition. The Ti islands cover the surface completely at about 12 ML of Ti deposition. XPD results show that the Ti overlayer has a well-ordered hcp Ti(0001) structure on the fcc Al(111) surface, in remarkable contrast to the fcc Ti film growth observed on Al(001) and Al(110) surfaces.

ALLOY FORMATION OF ULTRATHIN Ni FILMS ON Al(111) SURFACE AT ROOM TEMPERATURE

1999 ◽  
Vol 06 (05) ◽  
pp. 781-786 ◽  
Author(s):  
Y. W. KIM ◽  
G. A. WHITE ◽  
R. REIBEL ◽  
R. J. SMITH
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
High Energy ◽  
Alloy Formation ◽  
Ion Scattering ◽  
Xps Spectra ◽  
Ion Channeling ◽  
Low Energy Ion Scattering ◽  
Nial Phase ◽  
Nial Alloy

The growth characteristics of ultrathin Ni films deposited on Al(111) surfaces at room temperature have been studied using high energy ion scattering/channeling (HEIS), X-ray photoelectron spectroscopy (XPS) and low energy ion scattering (LEIS). Ion channeling results show that Ni atoms deposited on the Al(111) surface react with Al substrate atoms to form two different Ni–Al alloys between 0 and 5.5 ML of Ni coverage. Alloy phases of Ni 2 Al 3 up to 1.5 ML and NiAl up to 5.5 ML were determined by XPS peak analysis. At higher Ni coverage, LEIS and XPS spectra suggest that islands of Ni metal were formed on the surface. Diffusion of Ni into the Al substrate or segregation of Al to the surface was observed during the alloy formation. The Ni 2 Al 3 phase was apparently transformed into the NiAl phase by the additional Ni deposition, and the islands of Ni metal formed on the Al-rich surface of the NiAl alloy.

Low-energy ion scattering spectroscopy and reflection high-energy electron diffraction of native oxides on GaN(0001)

2017 ◽  
Vol 56 (12) ◽  
pp. 128004 ◽  
Author(s):  
Yoshihiro Irokawa ◽  
Taku T. Suzuki ◽  
Kazuya Yuge ◽  
Akihiko Ohi ◽  
Toshihide Nabatame ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
High Energy ◽  
Low Energy ◽  
Energy Electron ◽  
High Energy Electron ◽  
Ion Scattering ◽  
Native Oxides ◽  
Low Energy Ion Scattering ◽  
Ion Scattering Spectroscopy

Epitaxy of Au on Ag(111) Studied by High-Energy Ion Scattering

1981 ◽  
Vol 47 (9) ◽  
pp. 657-660 ◽  
Author(s):  
R. J. Culbertson ◽  
L. C. Feldman ◽  
P. J. Silverman ◽  
H. Boehm
Keyword(s):  
High Energy ◽  
Ion Scattering

A Study on the Growth of Cubic GaN Films Using an AlGaAs Buffer Layer Grown on GaAs (100) by Plasma-Assisted Molecular Beam Epitaxy

2000 ◽  
Vol 639 ◽  
Author(s):  
Ryuhei Kimura ◽  
Kiyoshi Takahashi ◽  
H. T. Grahn
Keyword(s):  
Molecular Beam Epitaxy ◽  
Buffer Layer ◽  
Molecular Beam ◽  
High Energy ◽  
Rf Plasma ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cubic Gan

ABSTRACTAn investigation of the growth mechanism for RF-plasma assisted molecular beam epitaxy of cubic GaN films using a nitrided AlGaAs buffer layer was carried out by in-situ reflection high energy electron diffraction (RHEED) and high resolution X-ray diffraction (HRXRD). It was found that hexagonal GaN nuclei grow on (1, 1, 1) facets during nitridation of the AlGaAs buffer layer, but a highly pure, cubic-phase GaN epilayer was grown on the nitrided AlGaAs buffer layer.

Sign in / Sign up

Export Citation Format

Share Document