scholarly journals Microstructure of Compositionally Modulated InAlAs

1996 ◽  
Vol 441 ◽  
Author(s):  
R. D. Twesten ◽  
J. Mirecki Millunchick ◽  
S. P. Ahrenkielt ◽  
Yong Zhangt ◽  
S. R. Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Growth Front ◽  
Wavelength Modulation ◽  
Reciprocal Space Mapping ◽  
X Ray ◽  
Composition Modulation ◽  
Transmission Electron ◽  
Short Period ◽  
Short Period Superlattices

AbstractWe have observed spontaneous, lateral composition modulation in tensile InAlAs alloy films grown as short-period superlattices on InP (001). We have analyzed these films using transmission electron microscopy, x-ray reciprocal space mapping, and polarized photoluminescence spectroscopy. We find the growth front is nonplanar, exhibiting ∼2nm deep cusps aligned with the In-rich regions of the compositionally modulated films. In addition to the measured 15nm wavelength modulation in the [110] direction, a modulation of 30nm wavelength is seen in the orthogonal [110] direction. The photoluminescence from the modulated layer is strongly polarized and red shifted by 0.22eV.

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.

scholarly journals Transmission Electron Microscopy and X-ray Diffraction Investigation of the Microstructure of Nanoscale Multilayer TiAlN/VN Grown by Unbalanced Magnetron Deposition

2004 ◽  
Vol 19 (4) ◽  
pp. 1093-1104 ◽  
Author(s):  
Q. Luo ◽  
D.B. Lewis ◽  
P.Eh. Hovsepian ◽  
W-D. Münz
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Growth Model ◽  
Growth Front ◽  
Columnar Structure ◽  
Layer Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Unbalanced Magnetron

Cubic NaCl-B1 structured multilayer TiAlN/VN with a bi-layer thickness of approximately 3 nm and atomic ratios of (Ti+Al)/V = 0.98 to 1.15 and Ti/V = 0.55 to 0.61 were deposited by unbalanced magnetron sputtering at substrate bias voltages between -75 and -150 V. In this paper, detailed transmission electron microscopy and x-ray diffraction revealed pronounced microstructure changes depending on the bias. At the bias -75 V, TiAlN/VN followed a layer growth model led by a strong (110) texture to form a T-type structure in the Thornton structure model of thin films, which resulted in a rough growth front, dense columnar structure with inter-column voids, and low compressive stress of -3.8 GPa. At higher biases, the coatings showed a typical Type-II structure following the strain energy growth model, characterized by the columnar structure, void-free column boundaries, smooth surface, a predominant (111) texture, and high residual stresses between -8 and -11.5 GPa.

scholarly journals Effect of screw threading dislocations and inverse domain boundaries in GaN on the shape of reciprocal-space maps

2017 ◽  
Vol 50 (2) ◽  
pp. 555-560 ◽  
Author(s):  
Mykhailo Barchuk ◽  
Mykhaylo Motylenko ◽  
Gleb Lukin ◽  
Olf Pätzold ◽  
David Rafaja
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Reciprocal Space ◽  
Threading Dislocations ◽  
X Ray Diffraction ◽  
Reciprocal Space Mapping ◽  
Vapour Phase Epitaxy ◽  
X Ray ◽  
Transmission Electron ◽  
Domain Boundaries

The microstructure of polar GaN layers, grown by upgraded high-temperature vapour phase epitaxy on [001]-oriented sapphire substrates, was studied by means of high-resolution X-ray diffraction and transmission electron microscopy. Systematic differences between reciprocal-space maps measured by X-ray diffraction and those which were simulated for different densities of threading dislocations revealed that threading dislocations are not the only microstructure defect in these GaN layers. Conventional dark-field transmission electron microscopy and convergent-beam electron diffraction detected vertical inversion domains as an additional microstructure feature. On a series of polar GaN layers with different proportions of threading dislocations and inversion domain boundaries, this contribution illustrates the capability and limitations of coplanar reciprocal-space mapping by X-ray diffraction to distinguish between these microstructure features.

Structural Characterization of Short-Period SimGEn Superlattices by Transmission Electron Microscopy and X-Ray Diffraction

1991 ◽  
Vol 220 ◽  
Author(s):  
W. Jäger ◽  
K. Leifer ◽  
P. Ehrhart ◽  
E. Kasper ◽  
H. Kibbel
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Interface Roughness ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
Average Composition ◽  
X Ray ◽  
Transmission Electron ◽  
Short Period

ABSTRACTHigh resolution and analytical transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to characterize short-period strained-layer Sim-Gen superlattices ( m monolayers Si, n monolayers Ge, total number of periods N≤ 145, total thickness ≃ 200 nm). The superlattices were grown by low-temperature molecular beam epitaxy (T = 300–400°C) on different SiGe alloy buffer layers on Si (100)substrates. The combination of these two methods shows that detailed informations can be obtained about superlattice periodicity, interface roughness, strain, and average composition.

scholarly journals Структурная характеризация короткопериодной сверхрешетки на основе гетероструктуры CdF-=SUB=-2-=/SUB=-/CaF-=SUB=-2-=/SUB=-/Si(111) методами просвечивающей электронной микроскопии и рентгеновской дифрактометрии

2021 ◽  
Vol 47 (15) ◽  
pp. 3
Author(s):  
Л.М. Сорокин ◽  
Р.Н. Кютт ◽  
В.В. Ратников ◽  
А.Е. Калмыков
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Fragment Size ◽  
Diffraction Curve ◽  
X Ray ◽  
Transmission Electron ◽  
Short Period ◽  
Lateral Inhomogeneity

A detailed study of the structure of a short-period superlattice based on alternating layers of cadmium and calcium fluorides, grown by molecular beam epitaxy on a Si (111) substrate, by transmission electron microscopy and X-ray diffractometry, has been carried out. It was found that the superlattice is in a pseudomorphic state, and a lateral inhomogeneity with a fragment size of 10 - 40 nm was found. The reason for the broadening of the main and satellite peaks of the SL on the (111) diffraction curve has been clarified.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

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