Interface Structure of Ge/Si Superlattices Determined by X-Ray Absorption Fine Structure

1991 ◽  
Vol 220 ◽  
Author(s):  
P. Aebi ◽  
T. Tyliszczak ◽  
A. P. Hitchcock ◽  
J. -M. Baribeau ◽  
D. J. Lockwood ◽  
...  
Keyword(s):  
Fine Structure ◽  
Bond Length ◽  
Strained Si ◽  
Raman Scattering Spectroscopy ◽  
X Ray ◽  
Absorption Fine ◽  
Nearest Neighbours ◽  
Short Period ◽  
Short Period Superlattices ◽  
X Ray Absorption

ABSTRACTWe illustrate the usefulness of the Extended X-ray Absorption Fine Structure (EXAFS) technique to determine the amount of interface mixing and strain condition in the study of (SimGen)p short-period superlattices. It is found that for n < 4, the number of Ge and Si nearest neighbours to Ge atoms is consistent with ∼25% interfacial mixing and that the Ge-Ge bond length corresponds to that of coherently strained Ge. The Si-Ge bond length is shorter, close to that of a strained Si0.25Ge0.75 alloy. For n > 4, the Ge-Ge bond length and the number of Si-Ge nearest neighbours increase significantly consistent with partial relaxation and interdiffusion. Raman scattering spectroscopy and x-ray reflectometry measurements are also presented and are consistent with the conclusions of the EXAFS analysis.

Bond length variation in Zn substituted NiO studied from extended X-ray absorption fine structure

2017 ◽  
Vol 259 ◽  
pp. 40-44 ◽  
Author(s):  
S.D. Singh ◽  
A.K. Poswal ◽  
C. Kamal ◽  
Parasmani Rajput ◽  
Aparna Chakrabarti ◽  
...  
Keyword(s):  
Fine Structure ◽  
Bond Length ◽  
Length Variation ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption

Extended X-ray Absorption Fine Structure Studies of InGaN Epilayers

2004 ◽  
Vol 831 ◽  
Author(s):  
V. Katchkanov ◽  
K.P. O'Donnell ◽  
J.F.W. Mosselmans ◽  
S. Hernandez ◽  
R.W. Martin ◽  
...  
Keyword(s):  
Fine Structure ◽  
Bond Length ◽  
Molar Fraction ◽  
Chemical Vapour ◽  
Organic Chemical ◽  
X Ray ◽  
Absorption Fine ◽  
Vegard’S Law ◽  
Metal Organic ◽  
X Ray Absorption

ABSTRACTThe local structure around In atoms in InGaN epilayers grown by Molecular Beam Epitaxy (MBE) and by Metal-Organic Chemical Vapour Deposition (MOCVD) was studied by means of Extended X-ray Absorption Fine Structure (EXAFS). The averaged In fraction of MOCVD grown samples ranged from 10% to 40% as estimated by Electron Probe Microanalysis (EPMA). The In fraction of MBE grown samples spanned the range from 13% to 96%. The In–N bond length was found to vary slightly with composition, both for MBE and MOCVD grown samples. Moreover, for the same In content, the In-N bond lengths in MOCVD samples were longer than those in MBE grown samples. In contrast, the In-In radial separations in MOCVD and MBE samples were found to be indistinguishable for the same In molar fraction. The In-Ga bond length was observed to deviate from average cation-cation distance predicted by Vegard's law for MBE grown samples which indicates alloy compositional fluctuations.

Bond-length anomaly in InP1−xAsx monolayers on InP(001) studied by extended x-ray absorption fine structure

1997 ◽  
Vol 82 (1) ◽  
pp. 214-218 ◽  
Author(s):  
Y. Kuwahara ◽  
H. Oyanagi ◽  
R. Shioda ◽  
Y. Takeda ◽  
H. Kamei ◽  
...  
Keyword(s):  
Fine Structure ◽  
Bond Length ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption

Characterization of ultrathin Ge epilayers on (100) Si

1991 ◽  
Vol 69 (3-4) ◽  
pp. 246-254 ◽  
Author(s):  
J. -M. Baribeau ◽  
D. J. Lockwood ◽  
T. E. Jackman ◽  
P. Aebi ◽  
T. Tyliszczak ◽  
...  
Keyword(s):  
Strain Relaxation ◽  
Three Dimensional ◽  
Raman Scattering Spectroscopy ◽  
X Ray ◽  
Transmission Electron ◽  
Short Period ◽  
Short Period Superlattices ◽  
Direct Band ◽  
X Ray Absorption

The understanding of the epitaxy of pure Ge layers on Si is an important step towards the synthesis of SimGen (m, n < 10 monolayers) short-period superlattices. The possibility of a direct band-gap character makes these structures extremely attractive. We have grown thin buried Gen ([Formula: see text] monolayers) films on (100) Si by molecular beam epitaxy and studied their structural properties by a variety of techniques including Raman scattering spectroscopy, glancing incidence X-ray reflection, Rutherford backscattering, transmission electron microscopy, and extended X-ray absorption fine structure analysis. All these techniques allowed detection of the thin Ge layers and provided information about the thickness, morphology, strain distribution, and interface sharpness of these heterostructures. The Ge„ films with [Formula: see text] had a two-dimensional nature and showed no sign of strain relaxation. Intermixing at the Si–Ge interfaces was present in all these films and estimated to be not more than two monolayers. This smearing at the interfaces may have contributed to the maintenance of that pseudomorphicity. A thicker Ge layer (n = 12) showed evidence of strain relaxation and clustering in three-dimensional islands.

Extended x-ray-absorption fine-structure determination of bond-length conservation at the clean InP(110) surface

1992 ◽  
Vol 46 (15) ◽  
pp. 9869-9872 ◽  
Author(s):  
J. C. Woicik ◽  
T. Kendelewicz ◽  
K. E. Miyano ◽  
M. Richter ◽  
C. E. Bouldin ◽  
...  
Keyword(s):  
Fine Structure ◽  
Bond Length ◽  
Structure Determination ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption

Surface extended X-ray absorption fine structure: critical appraisal of a structural tool for adsorbates

1986 ◽  
Vol 318 (1541) ◽  
pp. 203-217 ◽  
Keyword(s):  
Fine Structure ◽  
Bond Length ◽  
Intensity Analysis ◽  
X Ray ◽  
Absorption Fine ◽  
Data Analysis Procedure ◽  
Electron Storage Rings ◽  
X Ray Absorption ◽  
Monolayer Coverage

The availability of intense, tunable, polarized X-radiation from electron storage rings has led to the successful application of surface extended X-ray absorption fine structure (s.e.X.a.f.s.) measurements to the determination of inter-atomic spacings and, by using multishell analyses, complete structures for adsorbates on surfaces. Recent work on a surface iodide structure on Ni{100}, Ag{100}— c (2 x 2) Cl, Ag{111}—(/ 3 x /3 ) R 30°—Cl (0.7 fractional monolayer coverage) and disordered 0.4 monolayer Ag{111}—Cl structure are reviewed. The results for Cl on Ag{100} confirm a previous exhaustive I.e.e d. intensity analysis for the same system, but yield greater precision in the Cl—Ag bond length (2.69 + 0.03 A). Studies of Cl on Ag{111} were extended to low crystal temperatures, and demonstrate: (i) a significant improvement in signal quality; (ii) removal of anomalies due to anharmonicity at room temperature; and (iii) the ability of s.e.X.a.f.s., by using a multishell data analysis procedure including four atomic shells, to provide an unambiguous structure determination from both a poorly ordered and a disordered structure. The Cl—Ag bond length is found to be 2.70 + 0.01 A at both 0.4 and 0.7 fractional monolayer coverages.

Orientation and bond length of molecular oxygen on Ag(110) and Pt(111): A near-edge x-ray-absorption fine-structure study

1987 ◽  
Vol 35 (8) ◽  
pp. 4119-4122 ◽  
Author(s):  
D. A. Outka ◽  
J. Stöhr ◽  
W. Jark ◽  
P. Stevens ◽  
J. Solomon ◽  
...  
Keyword(s):  
Fine Structure ◽  
Bond Length ◽  
Molecular Oxygen ◽  
Structure Study ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption
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