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.

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.

Gas source molecular beam epitaxy and X-ray absorption fine structure characterization of InGaAs/InP short period superlattices

1994 ◽  
Vol 136 (1-4) ◽  
pp. 287-292 ◽  
Author(s):  
Teruo Mozume ◽  
Hideo Kashima ◽  
Kazuhiko Hosomi ◽  
Kiyoshi Ogata ◽  
Kazuhumi Suenaga ◽  
...  
Keyword(s):  
Fine Structure ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Structure Characterization ◽  
X Ray ◽  
Gas Source ◽  
Short Period ◽  
Short Period Superlattices ◽  
X Ray Absorption

scholarly journals Observation and Characterization of Fragile Organometallic Molecules Encapsulated in Single-Wall Carbon Nanotubes

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Daisuke Ogawa ◽  
Ryo Kitaura ◽  
Takeshi Saito ◽  
Shinobu Aoyagi ◽  
Eiji Nishibori ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
High Yield ◽  
Single Wall Carbon Nanotubes ◽  
X Ray Diffraction ◽  
Single Wall Carbon ◽  
X Ray ◽  
Transmission Electron ◽  
Organometallic Molecules ◽  
X Ray Absorption

Thermally fragile tris(η5-cyclopentadienyl)erbium (ErCp3) molecules are encapsulated in single-wall carbon nanotubes (SWCNTs) with high yield. We realized the encapsulation of ErCp3with high filling ratio by using high quality SWCNTs at an optimized temperature under higher vacuum. Structure determination based on high-resolution transmission electron microscope observations together with the image simulations reveals the presence of almost free rotation of each ErCp3molecule in SWCNTs. The encapsulation is also confirmed by X-ray diffraction. Trivalent character of Er ions (i.e., Er3+) is confirmed by X-ray absorption spectrum.

Solving the 3D structure of metal nanoparticles

2007 ◽  
Vol 222 (11/2007) ◽  
Author(s):  
Anatoly Frenkel
Keyword(s):  
Metal Nanoparticles ◽  
Short Range ◽  
Short Range Order ◽  
3D Structure ◽  
Three Dimensional ◽  
X Ray ◽  
Particle Distributions ◽  
Structure Of Metal ◽  
X Ray Absorption

We discuss methods of Extended X-ray Absorption Fine-Structure (EXAFS) analysis that provide three-dimensional structural characterization of metal nanoparticles, both mono- and bi-metallic. For the bimetallic alloys, we use short range order measurements to discriminate between random and non-random inter-particle distributions of atoms. We also discuss the application of EXAFS to heterogeneous nanoparticle systems.

Double Periodicity Formation in EuTe/PbTe Superlattices

1995 ◽  
Vol 399 ◽  
Author(s):  
M. Shima ◽  
L. Salamanca-Riba ◽  
G. Springholz ◽  
G. Bauer
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Short Period ◽  
Short Period Superlattices

ABSTRACTMolecular beam epitaxy was used to grow EuTe(x)/PbTe(y) short period superlattices with x=1-4 EuTe(111) monolayers alternating with y≈3x PbTe monolayers. The superlattices were characterized by transmission electron microscopy and high resolution x-ray diffraction. Regions with double periodicity were observed coexisting with areas of nominal periodicity. The sample with x=3.5 and y=9, for example, contains regions with double periodicity of x=7 and y=17. X-ray diffraction measurements confirm the formation of the double periodicity in these samples by the appearance of weak satellites in between the satellites of the nominal periodicity. The double periodicity in the superlattice is believed to result from interdiffusion during the growth. A model for this process is presented.

Structural Studies Of Epitaxial CdF2 Layers on Si(111)

1996 ◽  
Vol 441 ◽  
Author(s):  
A. Yu. Khilko ◽  
R. N. Kyutt ◽  
G. N. Mosina ◽  
N. S. Sokolov ◽  
Yu. V. Shusterman ◽  
...  
Keyword(s):  
Strain Relaxation ◽  
Optimal Growth ◽  
Misfit Strain ◽  
X Ray Diffraction ◽  
Optimal Growth Temperature ◽  
Light Emitting ◽  
X Ray ◽  
Light Emitting Devices ◽  
Transmission Electron

AbstractEpitaxial CdF2 layers, which may be used in light-emitting devices integrated with silicon, were grown by Molecular Beam Epitaxy (MBE). Characterization of the layers by Rutherford Backscattering Spectroscopy (RBS), X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) showed that optimal growth temperature lies in the range 60–80°C. The sticking coefficient of CdF2 molecules was found to decrease at temperatures above 100°C. Different modes of misfit strain relaxation were observed above and below that temperature.

scholarly journals Preparation and characterization of cobalt and copper oxide nanocrystals

2019 ◽  
Vol 37 (3) ◽  
pp. 347-352
Author(s):  
A. H. Moharram
Keyword(s):  
Microwave Irradiation ◽  
Copper Oxide ◽  
Chemical Precipitation ◽  
High Dispersion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Direct Band ◽  
Cuo Nanocrystals

AbstractCopper oxide and cobalt oxide (Co3O4, CuO) nanocrystals (NCs) have been successfully prepared using microwave irradiation. The obtained powders of the nanocrystals (NCs) were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric (TGA) analysis and Fourier-transform infrared spectroscopy. The obtained results confirm the presence of both nanooxides which have been produced during chemical precipitation using microwave irradiation. TEM micrographs have shown that the obtained nanocrystals are characterized by high dispersion and narrow size distribution. The results of X-ray diffraction confirmed those obtained from the transmission electron microscope. Optical absorption analysis indicated the direct band gap for both kinds of the nanocrystals.

Characterization of U(VI)-Acidithiobacillus ferrooxidans complexes using EXAFS, transmission electron microscopy, and energy-dispersive X-ray analysis

2003 ◽  
Vol 91 (10) ◽  
Author(s):  
Mohamed Merroun ◽  
C. Hennig ◽  
A. Rossberg ◽  
T. Reich ◽  
S. Selenska-Pobell
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Acidithiobacillus Ferrooxidans ◽  
Energy Dispersive ◽  
X Ray ◽  
Transmission Electron ◽  
Molecular Scale ◽  
X Ray Absorption

SummaryWe used a combination of Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy, Transmission Electron Microscopy (TEM) and Energy-Dispersive X-ray (EDX) analysis to conduct molecular scale studies on U(VI) interaction with three recently described eco-types of

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