Molecular Beam Epitaxial Growth of Gaas on Silicon with Buried Implanted Oxides

1987 ◽  
Vol 107 ◽  
Author(s):  
K. Das ◽  
T.P. Humphreys ◽  
J.B. Posthill ◽  
N. Parikh ◽  
J. Tarn ◽  
...  

AbstractWe report the first results of direct growth of GaAs by molecular beam epitaxy on nominally (100) oriented silicon with buried implanted oxides. Rutherford backscattering and transmission electron microscopy techniques have been used to characterize these layers. The formation of hillocks and a uniform layer of GaAs in the intervening regions between hillocks have been observed. Microtwins, dislocations and antiphase domain boundaries are the predominant defects observed in these layers.

1986 ◽  
Vol 90 ◽  
Author(s):  
N. Magnea ◽  
F. Dal'bo ◽  
J. L. Pautrat ◽  
A. Million ◽  
L. Di Cioccio ◽  
...  

ABSTRACTCD1−xZnxTe alloys of various composition have been grown by the Molecular Beam Epitaxy Technique and characterized by Transmission Electron Microscopy. C(V) measurements and photoluminescence spectroscopy techniques. The quality of the thick layers is comparable to that of bulk material. Thin strained layers have also been grown whose interfaces are structurally good. The recombination within a CdTe well confined between Cd1−xZnxTe barriers is dominated by intrinsic processes.


1988 ◽  
Vol 144 ◽  
Author(s):  
T. P. Humphreys ◽  
C. J. Miner ◽  
N. R. Parikh ◽  
K. Das ◽  
M. K. Summerville ◽  
...  

ABSTRACTEpitaxial GaAs layers have been grown by molecular beam epitaxy on (1012) sapphire and silicon-on-sapphire substrates. The grown layers were characterized by optical and transmission electron microscopy; Rutherford backscattering/channeling of 2.1 MeV He+ ions; Raman spectroscopy; Hall mobility measurements; photoluminescence spectroscopy and current-voltage measurements from metal-semiconductor contacts. The extensive microstructural, electrical and optical analysis of the GaAs layers indicates that the films deposited on silicon-on-sapphire are superior to those grown directly on (1012) sapphire substrates.


Author(s):  
P. R. Swann ◽  
W. R. Duff ◽  
R. M. Fisher

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.


1988 ◽  
Vol 53 (13) ◽  
pp. 1207-1209 ◽  
Author(s):  
J. B. Posthill ◽  
J. C. L. Tarn ◽  
K. Das ◽  
T. P. Humphreys ◽  
N. R. Parikh

1998 ◽  
Vol 13 (12) ◽  
pp. 3571-3579 ◽  
Author(s):  
U. Kaiser ◽  
S. B. Newcomb ◽  
W. M. Stobbs ◽  
M. Adamik ◽  
A. Fissel ◽  
...  

The effects of different growth parameters on the microstructure of the SiC films formed during simultaneous two-source molecular-beam-epitaxial (MBE) deposition have been investigated. Substrate temperatures as low as 750–900 °C have been used. The relationship between a number of different growth morphologies and deposition conditions has been established. The formation of single-crystal 3C films has been found to occur at low growth rates but within a limited Si: C adatom ratio. A combination of transmission electron microscopy (TEM) and atomic force microscopy (AFM) has been used to examine the different films, and the results of these investigations are described.


1991 ◽  
Vol 237 ◽  
Author(s):  
Mohan Krishnamurthy ◽  
M. Wassermeier ◽  
H. Weman ◽  
J. L. Merz ◽  
P. M. Petroffa

ABSTRACTA study of the molecular beam epitaxial (MBE) growth on singular and vicinal (110) surfaces of GaAs is presented. Quantum well structures and tilted superlattices (TSL) were grown on substrates misoriented 0.5°-2° towards the nearest [010] and [111]A azimuths at growth temperatures ranging from 450° C to 600° C under different growth conditions. The structures were characterized by Nomarski optical microscopy, transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy.Two types of faceting were observed on the surfaces. The structures grown at temperatures above 540°C and As beam fluxes below l×10-5 torr showed V-shaped facets pointing in the [001] direction and are attributed to As deficient island growth. Lower temperatures and higher As beam fluxes lead to surfaces with microfacets that are elongated along the respective step directions on the vicinal surface and are due to step bunching during growth. Their density and height decrease with decreasing vicinal angle and they disappear on the singular (110) surface. The photoluminescence of the GaAs quantum wells grown on these samples is redshifted with respect to that of the quantum wells grown on the flat surface. This is being ascribed to the fact that on the vicinal surface, the recombination takes place at the facets where the quantum wells are wider.The contrast in the TEM images of the TSL show for the samples misoriented towards [010] that the lateral segregation to the step edges on this surface is appreciable. The TSL spacing and the tilt however show that during growth the vicinal surfaces tend towards a surface with smaller miscut.


2D Materials ◽  
2021 ◽  
Author(s):  
Puspendu Guha ◽  
Joon Young Park ◽  
Janghyun Jo ◽  
Yunyeong Chang ◽  
Hyeonhu Bae ◽  
...  

Abstract We report on heteroepitaxial growth of Sb2Te3-Bi2Te3 lateral heterostructures using molecular beam epitaxy. The lateral heterostructures were fabricated by growing Bi2Te3 islands of hexagonal or triangular nanostructures with a typical size of several hundred nm and thickness of ~ 15 nm on graphene substrates and Sb2Te3 laterally on the side facets of the nanostructures. Multiple-step processes with different growth temperatures were employed to grow the lateral heterostructures. Electron microscopy techniques indicate that the inner region is Bi2Te3 and the outer Sb2Te3 was formed laterally on the graphene in an epitaxial manner. The interface between Bi2Te3 and Sb2Te3 from planar and cross-sectional views was studied by the aberration-corrected (Cs-corrected) high-angle annular dark-field scanning TEM (HAADF-STEM) technique. The cross-sectional electron microscopy investigation shows no wetting layer of Sb2Te3 on Bi2Te3, corroborating perfect lateral heterostructure formation. In addition, we investigated the topological properties of Sb2Te3-Bi2Te3 lateral heterostructures using first-principles calculations.


1995 ◽  
Vol 399 ◽  
Author(s):  
Olof Hellman ◽  
Shun-Ichiro Tanaka ◽  
Shigeru Niki ◽  
Paul Fons

ABSTRACTUsing Transmission Electron Microscopy, we examine the defect structure of Cu-rich and In-rich CuInSe2 films grown by Molecular Beam Epitaxy on GaAs (100) substrates. A surprisingly high density of cation sublattice stacking faults on (001) planes are observed in the Cu-rich films. Because these stacking faults are extremely flat and extend thousands of Ångstroms over the surface, and because they are not observed in other, non-Cu-rich films, we argue that they are a consequence of a surface structural change during growth, induced by the excess Cu. Two other types of defects are also observed: near the CuInSe2/GaAs interface, there is a high concentration of dislocations, stacking faults and domain boundaries. In the In-rich films, stacking faults and twin-type defects on {112} planes extend throughout the thickness of the grown film.


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