Compositional Modulations and Vertical Two-Dimensional Arsenic-Precipitate Arrays and in Low Temperature Grown Al0.3GA0.7AS

1993 ◽  
Vol 325 ◽  
Author(s):  
K.Y. Hsieh ◽  
Y.L. Hwang ◽  
T. Zhang ◽  
R.M. Kolbas
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Surface Layer ◽  
Molecular Beam ◽  
Two Dimensional ◽  
Cross Sectional ◽  
Metal Insulator ◽  
Compositional Modulation ◽  
Transmission Electron ◽  
Mis Diode

AbstractCompositional modulations and arsenic precipitates in annealed A10.3Ga0.7As layers which were grown at a low substrate temperature (200° C) by molecular beam epitaxy (MBE) were studied by transmission electron microscopy (TEM). These layers were used as surface layer which were applied on metal-insulator-semiconductor (MIS) diode. The planar and cross sectional TEM micrographs reveal that compositional modulations occurred when the thickness of LT AIGaAs was over 1500Å. The wavelength of the modulations varies between 100-200 Å and the direction of the modulation is along \011]. The arsenic precipitates were formed after annealed and the distribution of them followed the compositional modulation. Vertical two dimensional arsenic-precipitates arrays were arranged in the low aluminum constitute region. These novel microstructures result from the strain-induced spinodal decomposition and the arsenic precipitates redistribution process.

scholarly journals Structural Property Study for GeSn Thin Films

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3645
Author(s):  
Liyao Zhang ◽  
Yuxin Song ◽  
Nils von den Driesch ◽  
Zhenpu Zhang ◽  
Dan Buca ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Molecular Beam ◽  
Chemical Vapor ◽  
Threading Dislocations ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron

The structural properties of GeSn thin films with different Sn concentrations and thicknesses grown on Ge (001) by molecular beam epitaxy (MBE) and on Ge-buffered Si (001) wafers by chemical vapor deposition (CVD) were analyzed through high resolution X-ray diffraction and cross-sectional transmission electron microscopy. Two-dimensional reciprocal space maps around the asymmetric (224) reflection were collected by X-ray diffraction for both the whole structures and the GeSn epilayers. The broadenings of the features of the GeSn epilayers with different relaxations in the ω direction, along the ω-2θ direction and parallel to the surface were investigated. The dislocations were identified by transmission electron microscopy. Threading dislocations were found in MBE grown GeSn layers, but not in the CVD grown ones. The point defects and dislocations were two possible reasons for the poor optical properties in the GeSn alloys grown by MBE.

Relaxed Si1−xGex Layers on Simox Avoiding a Lattice Mismatched Heterointerface

1992 ◽  
Vol 263 ◽  
Author(s):  
B. Holländer ◽  
S. Mantl ◽  
R. Butz ◽  
W. Michelsen ◽  
Ch. Dieker
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Surface Layer ◽  
Rapid Thermal Annealing ◽  
Alternative Methods ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Yield Values ◽  
First Time ◽  
Minimum Yield

ABSTRACTFor the first time, Si1 xGex layers on amorphous SiO 2 were produced by modification of the Si surface layer of a SIMOX wafer. We used two alternative methods. An additional Si1.. Gey layer was deposited epitaxially on a SIMOX wafer followed by rapid thermal annealing. Diffusional intermixing of the layers produced a homogeneous Si1 xGex layer on SiO 2. In a second attempt, Ge was implanted into the Si surface layer and thermally treated. In both cases epitaxial Si1 xGex layers on SiO2 with minimum yield values around 9% were obtained. Rutherford backscattering and cross sectional transmission electron microscopy were used to characterize the new structures.

Two-Dimensional Damage Distributions Induced by Localized Ion Implantations

1992 ◽  
Vol 283 ◽  
Author(s):  
M. M. Faye ◽  
L. Laanab ◽  
J. Beauvillain ◽  
A. Claverie ◽  
C. Vieu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Two Dimensional ◽  
Cross Sectional ◽  
Quantum Nanostructures ◽  
Transmission Electron ◽  
Ion Beam Implantation ◽  
General Method

ABSTRACTA general method is presented for calculating the spatial distribution of damage generated by localized implantation in semiconductors. Implantation through masks and focused ion beam implantation in GaAs are simulated and compared to cross-sectional transmission electron microscopy observations. An excellent agreement is obtained when a depth-dependent lateral straggle is considered. Arbitrarily shaped mask edges and different compositions for the mask and the substrate are included in the calculations as well as realistic current profiles of the ion spot in the case of focused ion beam implantations. Simulations and experiments clearly demonstrate the potential application of localized implantations to fabricate lateral quantum nanostructures.

scholarly journals Analyzing the microstructure and related properties of 2D materials by transmission electron microscopy

2019 ◽  
Vol 49 (1) ◽  
Author(s):  
Yun-Yeong Chang ◽  
Heung Nam Han ◽  
Miyoung Kim
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Structural Variation ◽  
2D Materials ◽  
Transition Metal Dichalcogenide ◽  
Two Dimensional ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Transmission Electron ◽  
Two Dimensional Materials

Abstract Two-dimensional materials such as transition metal dichalcogenide and graphene are of great interest due to their intriguing electronic and optical properties such as metal-insulator transition based on structural variation. Accordingly, detailed analyses of structural tunability with transmission electron microscopy have become increasingly important for understanding atomic configurations. This review presents a few analyses that can be applied to two-dimensional materials using transmission electron microscopy.

Structures of Nb/Al2O3 Interfaces Produced by Different Experimental Routes

1990 ◽  
Vol 183 ◽  
Author(s):  
J. Mayer ◽  
W. Mader ◽  
D. Knauss ◽  
F. Ernst ◽  
M. Rühle
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molecular Beam ◽  
Al Alloy ◽  
Misfit Dislocations ◽  
Orientation Relationships ◽  
Cross Sectional ◽  
Mbe Growth ◽  
Sapphire Substrates ◽  
Transmission Electron

AbstractNb/Al2O3 interfaces were produced by (i) diffusion bonding of single crystalline Nb and Al2O3 at 1973 K, (ii) internal oxidation of a Nb-3at.% Al alloy at 1773 K, and (iii) molecular beam epitaxy (MBE) growth of 500 nm thick Nb overlayers on sapphire substrates at 1123 K. Cross-sectional specimens were prepared and studied by conventional (CTEM) and high resolution transmission electron microscopy (HREM). The orientation relationships between Nb and Al2O3 were identified by diffraction studies. HREM investigations revealed the structures of the different interfaces including the presence of misfit dislocations at or near the interface. The results for the different interfaces are compared.

Characterization of AlGaAs/InGaAs/GaAs Heteroepitaxial Layers by Transmission Electron Microscopy and Energy Dispersive Spectroscopy

1992 ◽  
Vol 281 ◽  
Author(s):  
R. S. Rai ◽  
J. M. Tartaglia ◽  
W. E. Quinn ◽  
D. C. Martel
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Energy Dispersive Spectroscopy ◽  
Molecular Beam ◽  
Energy Dispersive ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Periodic Striation ◽  
Heteroepitaxial Layers

ABSTRACTAlGaAs/InGaAs/GaAs heteroepitaxial layers grown by molecular beam epitaxy were studied by cross-sectional transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). The presence of waviness/roughness, fine periodic striation contrast due to Al composition oscillations, and defects were observed by TEM in selected samples. EDS on the TEM was of limited utility in determining the composition of thin epitaxial layers and in comparing the composition near and away from a defect. Arguments are presented to rationalize these results.

Investigation of the Shape of InGaAs/GaAs Quantum Dots

2002 ◽  
Vol 737 ◽  
Author(s):  
Susan Y. Lehman ◽  
Alexana Roshko ◽  
Richard P. Mirin ◽  
John E. Bonevich
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Molecular Beam ◽  
Length Scale ◽  
Cross Sectional ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Three Samples

ABSTRACTThree samples of self-assembled In0.44Ga0.56As quantum dots (QDs) grown on (001) GaAs by molecular beam epitaxy (MBE) were studied using atomic force microscopy (AFM) and high-resolution transmission electron microscopy (TEM) in order to characterize the height, faceting, and densities of the QDs. The cross-sectional TEM images show both pyramidal dots and dots with multiple side facets. Multiple faceting has been observed only in dots more than 8.5 nm in height and allows increased dot volume without a substantial increase in base area. Addition of a GaAs capping layer is found to increase the diameter of the QDs from roughly 40 nm to as much as 200 nm. The areal QD density is found to vary up to 50 % over the central 2 cm x 2 cm section of wafer and by as much as 23 % on a length scale of micrometers.

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