Epitaxial Layer Misorientation in CdTe on GaAs‡

1990 ◽  
Vol 202 ◽  
Author(s):  
H. E. Inglefield ◽  
R. J. Matyi ◽  
R. Korenstein
Keyword(s):  
Epitaxial Layer ◽  
Gaas Substrate ◽  
Dislocation Model ◽  
Azimuthal Direction ◽  
X Ray Diffraction ◽  
Azimuthal Dependence ◽  
X Ray ◽  
Gaas Substrates ◽  
Cdte Films ◽  
Hot Wall Epitaxy

ABSTRACTX-ray diffraction has been used to characterize the relative misorientation of [001] and [111] CdTe layers grown by hot-wall epitaxy on GaAs substrates. The magnitude of the misorientation of the CdTe epitaxial layer relative to the GaAs substrate depends on the magnitude of the miscut of the substrate; in addition, the [111] oriented CdTe exhibited significantly larger misorientations than did the [001] CdTe films. The azimuthal direction of the tilt of the epitaxial layer depends strongly on the nominal crystallographic orientation of the film. The [111] CdTe exhibited an azimuthal dependence of the tilt that is approximately coincident with the miscut of the substrate, while the azimuthal direction of tilt in the [001] CdTe layers differed from the substrate miscut direction by as much as 116°. These observations of epitaxial layer misorientation are discussed in terms of a dislocation model for layer tilt and azimuthal rotation in lattice-mismatched epitaxial systems.

Epitaxial tilt of partially relaxed InGaAs layers grown on (100) GaAs substrates

1992 ◽  
Vol 70 (10-11) ◽  
pp. 838-842
Author(s):  
P. Maigné ◽  
A. P. Roth ◽  
C. Desruisseaux ◽  
D. Coulas
Keyword(s):  
Residual Strain ◽  
Gaas Substrate ◽  
Strain Relaxation ◽  
Azimuthal Angle ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Monoclinic Symmetry ◽  
X Ray ◽  
Mismatch Strain ◽  
Gaas Substrates

The structural properties of partially relaxed InxGa1−xAs layers grown on (100) GaAs substrates have been investigated, using high-resolution X-ray diffraction, in order to better understand the mechanisms responsible for the relaxation of the mismatch strain. From symmetric [400] reflections recorded as functions of the azimuthal angle [Formula: see text], the (100) InGaAs planes are found to be tilted with respect to the (100) GaAs substrate planes. The tilt magnitude is first seen to decrease then to increase with layer thickness. The direction of the tilt changes from [01-1] to [00-1] in the range of thickness investigated. From [422] asymmetric reflections, the average in-plane lattice parameter, the indium composition as well as the percentage of relaxation can be measured. Our values for relaxation are in qualitative agreement with the Dodson and Tsao model of strain relaxation (Appl. Phys. Lett. 51, 1710 (1987)). In addition, our data show an anisotropy in residual strain along <011> directions. This anisotropy increases with the amount of strain relieved and changes the crystal symmetry of the cell from tetragonal to monoclinic. This monoclinic symmetry can be characterized by an angle β that measures the angle between 90° and the inner angles of the new crystallographic cell. As for the anisotropy in residual strain, |3 increases with the amount of strain relieved. Correlations between tilt magnitude and tilt direction with the formation of 60° type dislocations are discussed.

Ordered Ternary Alloys by Atomic Layer Epitaxy

1989 ◽  
Vol 160 ◽  
Author(s):  
B.T. Mcdermott ◽  
K.G. Reid ◽  
A. Dip ◽  
N.A. El-Masry ◽  
S.M. Bed Air ◽  
...  
Keyword(s):  
Gas Phase ◽  
Growth Temperature ◽  
Gaas Substrate ◽  
Atomic Layer ◽  
Ternary Alloys ◽  
Atomic Layer Epitaxy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Matching ◽  
Gaas Substrates

AbstractWe report on the successful growth of GalnP on GaAs substrate by Atomic Layer Epitaxy using organometallic and hydride sources. Growth was achieved by sequential exposure of the substrate to TMGa, PH3, TEIn and PH3. X-ray diffraction showed compositional lattice-matching optimally at 550°C with arbitrary choices of the mole fractions of the precursors in the gas phase. TEM also confirmed the highest ordering at this growth temperature on (100) substrates. Uniformity was excellent using Atomic Layer Epitaxy. Growth on (111)A GaAs substrates produced no evidence of the ordered CuPt phase present on (100) substrates.

Interfacial properties of GaSb/InAs superlattices

1993 ◽  
Vol 51 ◽  
pp. 826-827
Author(s):  
M. E. Twigg ◽  
B. R. Bennett ◽  
J. R. Waterman ◽  
J. L. Davis ◽  
B. V. Shanabrook ◽  
...  
Keyword(s):  
Gaas Substrate ◽  
Molecular Beam ◽  
Infrared Detector ◽  
Interfacial Properties ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
Absorption Coefficients ◽  
X Ray ◽  
Short Period ◽  
High Optical Absorption

Recently, the GaSb/InAs superlattice system has received renewed attention. The interest stems from a model demonstrating that short period Ga1-xInxSb/InAs superlattices will have both a band gap less than 100 meV and high optical absorption coefficients, principal requirements for infrared detector applications. Because this superlattice system contains two species of cations and anions, it is possible to prepare either InSb-like or GaAs-like interfaces. As such, the system presents a unique opportunity to examine interfacial properties.We used molecular beam epitaxy (MBE) to prepare an extensive set of GaSb/InAs superlattices grown on an GaSb buffer, which, in turn had been grown on a (100) GaAs substrate. Through appropriate shutter sequences, the interfaces were directed to assume either an InSb-like or GaAs-like character. These superlattices were then studied with a variety of ex-situ probes such as x-ray diffraction and Raman spectroscopy. These probes confirmed that, indeed, predominantly InSb-like and GaAs-like interfaces had been achieved.

Magnetic Anisotropy in Electrodeposited CO Films and spin-valves on Gaas Substrates

1999 ◽  
Vol 562 ◽  
Author(s):  
K. Attenborough ◽  
M. Cerisier ◽  
H. Boeve ◽  
J. De Boeck ◽  
G. Borghs ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Buffer Layer ◽  
Structural Properties ◽  
Easy Axis ◽  
Spin Valve ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cu Films ◽  
Gaas Substrates ◽  
Unique Spin

ABSTRACTWe have studied the magnetic and structural properties of thin electrodeposited Co and Cu layers grown directly onto (100) n-GaAs and have investigated the influence of a buffer layer. A dominant fourfold anisotropy with a uniaxial contribution is observed in 10 nm Co electrodeposited films on GaAs. An easy axis is observed in the [001] GaAs direction with two hard axes of differing coercivities parallel to the [011] and [011] directions. For thicker films the easy axes in the [001] direction becomes less pronounced and the fourfold anisotropy becomes less dominant. Co films of similar thicknesses deposited onto an electrodeposited Cu buffer layer were nearly isotropic. From X-ray diffraction 21 nm Co layers on GaAs were found to be hcp with the c-axis tending to be in the plane of the film. The anisotropy is ascribed to the Co/GaAs interface and is held responsible for the unique spin-valve properties seen recently in electrodeposited Co/Cu films.

scholarly journals Grazing-incidence X-ray diffraction of single GaAs nanowires at locations defined by focused ion beams

2013 ◽  
Vol 46 (4) ◽  
pp. 887-892 ◽  
Author(s):  
Genziana Bussone ◽  
Rüdiger Schott ◽  
Andreas Biermanns ◽  
Anton Davydok ◽  
Dirk Reuter ◽  
...  
Keyword(s):  
Gaas Substrate ◽  
Lattice Spacing ◽  
Molecular Beam ◽  
Grazing Incidence ◽  
Lattice Parameter ◽  
Ion Beams ◽  
Focused Ion Beams ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gaas Nanowires

Grazing-incidence X-ray diffraction measurements on single GaAs nanowires (NWs) grown on a (111)-oriented GaAs substrate by molecular beam epitaxy are reported. The positions of the NWs are intentionally determined by a direct implantation of Au with focused ion beams. This controlled arrangement in combination with a nanofocused X-ray beam allows the in-plane lattice parameter of single NWs to be probed, which is not possible for randomly grown NWs. Reciprocal space maps were collected at different heights along the NW to investigate the crystal structure. Simultaneously, substrate areas with different distances from the Au-implantation spots below the NWs were probed. Around the NWs, the data revealed a 0.4% decrease in the lattice spacing in the substrate compared with the expected unstrained value. This suggests the presence of a compressed region due to Au implantation.

X-ray diffraction analysis of a selectively grown InGaAsP epitaxial layer

2001 ◽  
Vol 90 (7) ◽  
pp. 3255-3262 ◽  
Author(s):  
Kiichi Nakashima ◽  
Yoshihiro Kawaguchi
Keyword(s):  
Diffraction Analysis ◽  
Epitaxial Layer ◽  
X Ray Diffraction ◽  
X Ray

Defect Reduction in Cd1-xZnxTe Epilayers on GaAs Substrates

1994 ◽  
Vol 299 ◽  
Author(s):  
Saket Chadda ◽  
Kevin Malloy ◽  
John Reno
Keyword(s):  
Threading Dislocation ◽  
Full Width ◽  
X Ray Diffraction ◽  
Defect Reduction ◽  
X Ray ◽  
Gaas Substrates ◽  
Transmission Electron ◽  
Threading Dislocation Density ◽  
Optimum Period ◽  
Bulk Alloys

AbstractCd0.91Zn0.09Te/CdTe multilayers of various period thicknesses were inserted into Cd0.955Zn0.045Te bulk alloys grown on (001) GaAs. The net strain of the multilayer on the underlying Cd0.955Zn0.045Te was designed to be zero. X-ray diffraction full width at half maximum (FWHM) was used as a means to optimize the period thickness of the multilayer. Transmission electron microscopy of the optimum period thickness samples demonstrated four orders of magnitude decrease in the threading dislocation density. Mechanism of bending by equi-strained multilayers is discussed.

Evaluation of threading dislocation density of strained Ge epitaxial layer by high resolution x-ray diffraction

2017 ◽  
Vol 26 (12) ◽  
pp. 127309 ◽  
Author(s):  
Yuan-Hao Miao ◽  
Hui-Yong Hu ◽  
Xin Li ◽  
Jian-Jun Song ◽  
Rong-Xi Xuan ◽  
...  
Keyword(s):  
High Resolution ◽  
Dislocation Density ◽  
Epitaxial Layer ◽  
Threading Dislocation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Threading Dislocation Density

High resolution X-ray diffraction studies of CdxHg1-xTe/CdTe epitaxial layers grown by MOVPE on GaAs substrates

1990 ◽  
Vol 101 (1-4) ◽  
pp. 572-578 ◽  
Author(s):  
A.M. Keir ◽  
A. Graham ◽  
S.J. Barnett ◽  
J. Giess ◽  
M.G. Astles ◽  
...  
Keyword(s):  
High Resolution ◽  
Epitaxial Layers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gaas Substrates

InAs Quantum Dots Grown on an AlGaAsSb Strain-Relief Buffer

2000 ◽  
Vol 642 ◽  
Author(s):  
A.L. Gray ◽  
L. R. Dawson ◽  
Y. Lin ◽  
A. Stintz ◽  
Y.-C. Xin ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Cross Section ◽  
Gaas Substrate ◽  
Buffer Layers ◽  
Threading Dislocations ◽  
X Ray Diffraction ◽  
Strain Relief ◽  
Inas Quantum Dots ◽  
X Ray ◽  
Transmission Electron

ABSTRACTAn In(Ga)As-based self-assembled quantum dot laser test structure grown on strain-relief Al0.5Ga0.5As1-ySby strain-relief buffer layers (0≤y ≤ 0.24) on a GaAs substrate is investigated in an effort to increase dot size and therefore extend the emission wavelength over conventional InAs quantum dots on GaAs platforms. Cross-section transmission electron microscopy, and high-resolution x-ray diffraction are used to monitor the dislocation filtering process and morphology in the buffer layers. Results show that the buffer layers act as an efficient dislocation filter by drastically reducing threading dislocations, thus providing a relaxed, low dislocation, compositionally modulated Al0.5Ga0.5Sb0.24As0.76 substrate for large (500Å height x 300Å width) defect -free InAs quantum dots. Photoluminescence shows a ground-state emission of the InAs quantum dots at 1.45 μm.

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