Characterization of high-quality epitaxial AlN films grown by MOVPE

2001 ◽  
Vol 693 ◽  
Author(s):  
Tomohiko Shibata ◽  
Keiichiro Asai ◽  
Teruyo Nagai ◽  
Shigeaki Sumiya ◽  
Mitsuhiro Tanaka ◽  
...  
Keyword(s):  
Surface Region ◽  
Epitaxial Films ◽  
High Quality ◽  
Edge Type ◽  
X Ray ◽  
Organic Vapor ◽  
Transmission Electron ◽  
Metal Organic ◽  
Almost All

AbstractThis paper presents the correlation between overall crystal mosaicities and dislocation behaviors of high-quality AlN epitaxial films grown on a C-plane sapphire substrate using a low-pressure metal organic vapor phase epitaxy (LP-MOVPE) method. Typical full width at half maximum (FWHM) values of x-ray rocking curves (XRC) for (0002) and (10-10) of the AlN are 80arcsec and 1800arcsec, respectively. From transmission electron microscopy (TEM) observations, edge-type dislocations thread the AlN layer, however, almost all screw-type dislocations disappear at an early AlN growth stage. The dislocation density of the AlN films in its surface region is as low as approximately 1x1010 cm-2. The distribution of the dislocations is considered to be caused by a large twisted mosaicity and a very small tilted mosaicity.

Compositional control and structural properties of ZnSe1-xTex epitaxial films on lattice- matched InGaAs/InP (001) by photoassisted Metal Organic Vapor Phase Expitaxy (MOVPE)

2004 ◽  
Vol 819 ◽  
Author(s):  
Bhanu Prakash Yarlagadda ◽  
Angel Rodriguez ◽  
Peng Li ◽  
John Ayers ◽  
Faquir Jain
Keyword(s):  
Gas Phase ◽  
Vapor Phase ◽  
Structural Data ◽  
Epitaxial Films ◽  
Lower Growth ◽  
X Ray ◽  
Organic Vapor ◽  
Metal Organic ◽  
Compositional Control ◽  
Lattice Matched

AbstractWe report the growth of ZnSe1−xTex (x < 0.9) epitaxial layers using photoassisted Metal- Organic Vapor Phase Epitaxy (MOVPE) on lattice-matched InGaAs/InP (001) substrates. Ternary compositional control was studied as a function of the gas phase composition, growth temperature (360°C – 400°C) and irradiation (12 mW/cm2 – 48mW/cm2). Compositional and structural data were obtained by x-ray rocking curves from 004 and 044 reflections. Lower growth temperatures increased the relative tellurium incorporation but at the expense of the growth rate.

scholarly journals Mechanism for Improved Quality B12As2 Epitaxial Films on (0001) 4H-SiC Substrates by Tilting toward [1-100] Direction

2010 ◽  
Vol 1246 ◽  
Author(s):  
Yu Zhang ◽  
Hui Chen ◽  
Michael Dudley ◽  
Yi Zhang ◽  
James Edgar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Substrate Surface ◽  
Epitaxial Films ◽  
High Quality ◽  
X Ray ◽  
Transmission Electron ◽  
Device Applications ◽  
Substrate Choice ◽  
Single Orientation

AbstractIn this work, 4H-SiC substrates intentionally misoriented from the (0001) plane toward [1-100] direction are shown to eliminate rotational twinning in icosahedral boron arsenide (B12As2, abbreviated here as IBA) epitaxial films. Previous studies of IBA on other substrates, including (100), (110), (111) Si and (0001) 6H-SiC, produced polycrystalline and twinned epilayers. Comparisons of IBA on on-axis and off-axis c-plane 4H-SiC by synchrotron white beam x-ray topography (SWBXT), and high resolution transmission electron microscopy (HRTEM) confirm the single crystalline and much higher quality of the films on the latter substrates. Furthermore, no intermediate layer between the epilayer and substrate was observed for IBA on off-axis 4H-SiC. Steps formed on the off-axis 4H-SiC substrate surface before deposition cause the film to adopt a single orientation, a process that is not seen with substrates with either no misorientation, or those tilted toward the [11-20] direction. This work demonstrates that c-plane 4H-SiC with 7° offcut toward (1-100) is potentially a good substrate choice for the growth of high-quality, untwinned B12As2 epilayers for future device applications.

Ordering in GaxIn1−xAsyP1−y Detected by Diffraction Methods

1995 ◽  
Vol 417 ◽  
Author(s):  
I. Rechenberg ◽  
A. Oster ◽  
A. Knauer ◽  
U. Richter ◽  
J. Menniger ◽  
...  
Keyword(s):  
High Resolution ◽  
Miscibility Gap ◽  
X Ray Diffraction ◽  
Temperature Behaviour ◽  
Anomalous Temperature ◽  
X Ray ◽  
Organic Vapor ◽  
Transmission Electron ◽  
Metal Organic ◽  
Lattice Matched

AbstractGa0.54In0.46As0.12P0.88 lattice matched to GaAs and grown by metal organic vapor phase epitaxy (MOVPE) shows an anomalous temperature behaviour of its cathodoluminescence (CL) emission. Using high resolution x-ray diffraction (HRXRD) and transmission electron diffraction (TED), ordering in this quarternary alloy can be identified as the reason for this behaviour. The ordering follows the same trends with respect to misorientation that are known for InGaP. In addition to ordering, compositional fluctuations related to a miscibility gap are found in this material. In contrast, layers with a higher As-content (y=0.5; y=0.76) do not show properties related to ordering.

Characterization of Pb(ScTa)1−xTixO3 (x<0.3) Thin Films Grown on LaNiO3 Coated Si by MOCVD

1998 ◽  
Vol 541 ◽  
Author(s):  
C. H. Lin ◽  
H. C. Kuo ◽  
G. E. Stillman ◽  
Haydn Chen
Keyword(s):  
Thin Films ◽  
Electron Microscope ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates ◽  
Transmission Electron ◽  
Metal Organic

AbstractHighly (100) textured pseudo-cubic Pb(ScTa)1−xTixO3 (x=0-0.3) (PSTT) thin films were grown by metal-organic chemical vapor deposition (MOCVD) on LaNiO3 (LNO) electrode buffered Si substrates at 650 °C. The microstructure and chemical uniformity were studied using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and nanoprobe X-ray energy dispersive spectroscopy (EDS). The temperature dependence of dielectric properties and P-E behavior were measured. A shift of Curie temperature of these PST-based thin films due to Ti addition was demonstrated, Furthermore, the pyroelectric properties of these thin films were estimated.

scholarly journals Исследования поперечного среза и фотолюминесценции слоя GaAs, выращенного на подложке Si/Al-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=-

2019 ◽  
Vol 53 (9) ◽  
pp. 1271
Author(s):  
А.А. Сушков ◽  
Д.А. Павлов ◽  
В.Г. Шенгуров ◽  
C.А. Денисов ◽  
В.Ю. Чалков ◽  
...  
Keyword(s):  
Gaas Layer ◽  
Optical Quality ◽  
Buffer Layers ◽  
Structural Studies ◽  
Hot Wire ◽  
X Ray ◽  
Organic Vapor ◽  
Transmission Electron ◽  
Metal Organic

AbstractA GaAs/AlAs/GaAs/AlAs/Ge heterostructure grown on a Si/Al_2O_3(1 $$\bar {1}$$ 02) substrate is formed and studied. The Ge buffer layer is produced by the “hot wire” technique, whereas the III–V layers are grown by metal–organic vapor-phase epitaxy. The optical quality of the III–V layers is determined by photoluminescence spectroscopy. Structural studies are performed by high-resolution transmission electron microscopy. The elemental composition is determined by energy-dispersive X-ray spectroscopy. In the study, the possibility of growing a single-crystal GaAs layer on a Si/Al_2O_3 substrate through AlAs/GaAs/AlAs/Ge buffer layers is shown.

High-Quality GaInAsSb and GaAlAsSb Layers for Thermophotovoltaics Grown by Liquid-Phase Epitaxy

2010 ◽  
Vol 159 ◽  
pp. 87-90
Author(s):  
M. Milanova ◽  
Roumen Kakanakov ◽  
G. Koleva ◽  
P. Vitanov ◽  
V. Bakardjieva ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Liquid Phase Epitaxy ◽  
X Ray Diffraction ◽  
High Quality ◽  
X Ray ◽  
Al Content ◽  
Quaternary Compounds ◽  
Transmission Electron

GaSb based III-V heterostuctures are attractive for optoelectronic devices such as midin- frared lasers, detectors, and thermophotovoltaics (TPVs). In this paper the growth and characterization of GaInAsSb and GaAlAsSb quaternary layers, lat-tice-matched to GaSb substrate, are reported, with a particular focus on these alloys for TPV devi-ces. High-quality with a mirror-like surface morphology epilayers Ga1-x InxAsy Sb1-y with In content x in the range 0.1-0.22 and Ga1-xAlxAsySb1-y layers with Al content up to 0.3 in the solid are grown by Liquid-Phase Epitaxy (LPE) from In- and Ga-rich melt, respectively. The compositions of the quaternary compounds are determined by X-ray microanalysis. The crystalline quality of GaInAsSb/ GaSb and GaAlAsSb/GaSb heterostuctures is studied by X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements.

Elimination of Degenerate Epitaxy in the Growth of High Quality B12As2 Single Crystalline Epitaxial Films

2011 ◽  
Vol 1307 ◽  
Author(s):  
Yu Zhang ◽  
Hui Chen ◽  
Michael Dudley ◽  
Yi Zhang ◽  
J. H. Edgar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Epitaxial Films ◽  
High Quality ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Single Orientation

ABSTRACTElimination of degenerate epitaxy in the growth of icosahedral boron arsenide (B12As2, abbreviated as IBA) was achieved on m-plane 15R-SiC substrates and 4H-SiC substrates intentionally misoriented by 7 degrees from (0001) towards [1-100]. Synchrotron white beam x-ray topography (SWBXT) revealed that only single orientation IBA was present in the epitaxial layers demonstrating the absence of twin variants which dominantly constitute the effects of degenerate epitaxy. Additionally, low asterism in the IBA diffraction spots compared to those grown on other SiC substrates indicates a superior film quality. Cross-sectional high resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy (STEM) both confirmed the absence of twins in the IBA films and their high quality. The ease of nucleation on the ordered step structures present on these unique substrates overrides symmetry considerations that drive degenerate epitaxy and dominates the nucleation process of the IBA.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

scholarly journals Synthesis and characterization of Fe, Co, and Ni colloids in 2-mercaptoethanol

2020 ◽  
Vol 10 ◽  
pp. 184798042096688
Author(s):  
Galo Cárdenas-Triviño ◽  
Sergio Triviño-Matus
Keyword(s):  
Electron Microscopy ◽  
Electron Diffraction ◽  
Colloidal Dispersions ◽  
Synthesis And Characterization ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Chemical Liquid Deposition ◽  
Liquid Deposition

Metal colloids in 2-mercaptoethanol using nanoparticles (NPs) of iron (Fe), cobalt (Co), and nickel (Ni) were prepared by chemical liquid deposition method. Transmission electron microscopy, electron diffraction, UV-VIS spectroscopy, and scanning electron microscopy with electron dispersive X-ray spectroscopy characterized the resulting colloidal dispersions. The NPs exhibited sizes with ranges from 9.8 nm for Fe, 3.7 nm for Co, and 7.2 nm for Ni. The electron diffraction shows the presence of the metals in its elemental state Fe (0), Co (0), and Ni (0) and also some compounds FeO (OH), CoCo2S4, and NiNi2S4.

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