Interface Quality and Interdiffusion in Si-Ge Heterostructures

1993 ◽  
Vol 312 ◽  
Author(s):  
J.-M. Baribeau ◽  
D. J. Lockwood ◽  
G. C. Aers ◽  
M. W. C. Dharma-Wardana
Keyword(s):  
Raman Scattering ◽  
Composition Dependence ◽  
Isothermal Annealing ◽  
Atomic Displacement ◽  
Strong Decay ◽  
Optical Mode ◽  
Interface Quality ◽  
Raman Scattering Spectroscopy ◽  
X Ray ◽  
Short Period

AbstractThe evolution of interfaces of short-period (SimGen)p superlattices upon annealing has been studied by x-ray reflectometry and Raman scattering spectroscopy. Isothermal annealing treatments at 700° C resulted in a significant material redistribution as evidenced by a strong decay of the superlattice x-ray satellites and by the decay of longitudinal acoustic modes and changes in the optical mode intensity ratios in Raman scattering. Interdiffusion was more pronounced in superlattices of short periodicity. This may possibly be explained by the strong composition dependence of the diffusivity of Ge atoms in Sil-xGex alloys and the degree of preexisting interfacial mixing. This composition dependence of the diffusion may favor atomic displacement parallel to the interfaces leading to an initial smoothing of the interfaces

Strain Shift Coefficients for Phonons in Si-Ge Heterostructures

1991 ◽  
Vol 239 ◽  
Author(s):  
J.-M. Baribeau ◽  
D. J. Lockwood
Keyword(s):  
Molecular Beam ◽  
Composition Dependence ◽  
Vibration Mode ◽  
Phonon Frequency ◽  
Longitudinal Optical ◽  
Stress Factor ◽  
Double Crystal ◽  
Raman Scattering Spectroscopy ◽  
X Ray ◽  
Shift Coefficient

ABSTRACTStrain shift coefficient measurements for longitudinal optical phonons in molecular beam epitaxy grown metastable pseudomorphic Si1−xGex layers on (100) Si (0 < x < 0.35) and Ge (0.80 < x < 1) are reported. Strain in partially relaxed annealed specimens was obtained by double-crystal x-ray diffractometry and the corresponding strain phonon shift was measured by Raman scattering spectroscopy. For epilayers grown on Si it was found that the epilayer Si-Si phonon frequency varies linearly with strain. The magnitude of the strain shift coefficient b however showed a small composition dependence varying from b ≈ -700 cm-1 at x = 0 to b ≈ -950 cm-1 at x = 0.35, corresponding to a stress factor τ = 0.40 + 0.57x: + 0.13x2 cm-1/kbar. For the Ge-Ge vibration mode in epilayers grown on Ge, b decreased from ∼-425 cm-1 at x = 1 to ∼-500 cm-1 at x = 0.8, corresponding to a stress factor τ ≈ 0.52 – 0.14x - 0.08x2 cm-1/kbar.

scholarly journals A large-solid-angle X-ray Raman scattering spectrometer at ID20 of the European Synchrotron Radiation Facility

2017 ◽  
Vol 24 (2) ◽  
pp. 521-530 ◽  
Author(s):  
S. Huotari ◽  
Ch. J. Sahle ◽  
Ch. Henriquet ◽  
A. Al-Zein ◽  
K. Martel ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Raman Scattering ◽  
Solid Angle ◽  
European Synchrotron Radiation Facility ◽  
Electronic Excitations ◽  
Raman Scattering Spectroscopy ◽  
X Ray ◽  
Area Detector ◽  
Spectroscopic Tool

An end-station for X-ray Raman scattering spectroscopy at beamline ID20 of the European Synchrotron Radiation Facility is described. This end-station is dedicated to the study of shallow core electronic excitations using non-resonant inelastic X-ray scattering. The spectrometer has 72 spherically bent analyzer crystals arranged in six modular groups of 12 analyzer crystals each for a combined maximum flexibility and large solid angle of detection. Each of the six analyzer modules houses one pixelated area detector allowing for X-ray Raman scattering based imaging and efficient separation of the desired signal from the sample and spurious scattering from the often used complicated sample environments. This new end-station provides an unprecedented instrument for X-ray Raman scattering, which is a spectroscopic tool of great interest for the study of low-energy X-ray absorption spectra in materials under in situ conditions, such as in operando batteries and fuel cells, in situ catalytic reactions, and extreme pressure and temperature conditions.

Hydration in aqueous solutions of ectoine and hydroxyectoine

2018 ◽  
Vol 20 (44) ◽  
pp. 27917-27923 ◽  
Author(s):  
Christoph J. Sahle ◽  
Martin A. Schroer ◽  
Cy M. Jeffries ◽  
Johannes Niskanen
Keyword(s):  
Raman Scattering ◽  
Aqueous Solutions ◽  
Pure Water ◽  
Raman Scattering Spectroscopy ◽  
X Ray

We explore the influence of the two osmolytes ectoine and hydroxyectoine on the structure of pure water and aqueous NaCl solutions using non-resonant X-ray Raman scattering spectroscopy at the oxygen K-edge.

Hydration in aqueous osmolyte solutions: the case of TMAO and urea

2020 ◽  
Vol 22 (20) ◽  
pp. 11614-11624 ◽  
Author(s):  
Christoph J. Sahle ◽  
Martin A. Schroer ◽  
Johannes Niskanen ◽  
Mirko Elbers ◽  
Cy M. Jeffries ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Raman Scattering ◽  
Aqueous Solutions ◽  
First Principles ◽  
Raman Scattering Spectroscopy ◽  
X Ray ◽  
Bond Topology

X-ray Raman scattering spectroscopy and first principles simulations reveal details of the hydration and hydrogen-bond topology of trimethylamine N-oxide (TMAO) and urea in aqueous solutions.

Oxygen K-edge fine structures of water by x-ray Raman scattering spectroscopy under pressure conditions

2007 ◽  
Vol 127 (13) ◽  
pp. 134502 ◽  
Author(s):  
Hiroshi Fukui ◽  
Simo Huotari ◽  
Denis Andrault ◽  
Tatsuhiko Kawamoto
Keyword(s):  
Raman Scattering ◽  
Raman Scattering Spectroscopy ◽  
X Ray ◽  
Fine Structures

scholarly journals In situ characterization of the decomposition behavior of Mg(BH4)2 by X-ray Raman scattering spectroscopy

2016 ◽  
Vol 18 (7) ◽  
pp. 5397-5403 ◽  
Author(s):  
Christoph J. Sahle ◽  
Simon Kujawski ◽  
Arndt Remhof ◽  
Yigang Yan ◽  
Nicholas P. Stadie ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Raman Scattering ◽  
Hydrogen Atmosphere ◽  
In Situ Characterization ◽  
Raman Scattering Spectroscopy ◽  
X Ray ◽  
Decomposition Behavior

We present an in situ study of the thermal decomposition of Mg(BH4)2 in a hydrogen atmosphere of up to 4 bar and up to 500 °C using X-ray Raman scattering spectroscopy at the boron K-edge and the magnesium L2,3-edges.

Epitaxy of SimGen Atomic Layer Superlattices

1989 ◽  
Vol 160 ◽  
Author(s):  
J.-M. Baribeau ◽  
DJ. Lockwood ◽  
N.L. Rowell ◽  
M.W.C. Dharma-Wardana ◽  
D.C. Houghton ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Raman Scattering ◽  
Structural Properties ◽  
Atomic Layer ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
Mbe Growth ◽  
Raman Scattering Spectroscopy ◽  
X Ray ◽  
Luminescent Signal

AbstractWe report the MBE growth of various (SimGen)p atomic layer superlattices (ALS) and their characterization by Raman scattering spectroscopy, x-ray diffraction and photoluminescence. The structural properties of ALS prepared on (100) Si, (100) Ge and on various Si1-xGex (0.5<×<1) buffers were compared. Phonon peaks due to folding of acoustic modes were seen by Raman scattering spectroscopy in the frequency range 15-250 cm-1. The observed Raman spectra from the ALS were interpreted on the basis of a theoretical analysis of these systems. The study provided an estimation of the interfacial sharpness of the ALS. The photoluminescence investigation on annealed specimens revealed features between 800 and 900 meV that were ascribed to known dislocation lines in Si. No strong luminescent signal that could be unambiguously related to a direct bandgap behavior was detected.

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.

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