Molecular Beam Epitaxy of Single Crystal Colossal Magneto-Resistive Material

1995 ◽  
Vol 401 ◽  
Author(s):  
J. N. Eckstein ◽  
I. Bozovic ◽  
M. Rzchowski ◽  
J. O'donnell ◽  
B. Hinaus ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Atomic Layer ◽  
Growth Conditions ◽  
Dislocation Network ◽  
Layer By Layer ◽  
Flat Surfaces ◽  
Low Field ◽  
Resistive Material ◽  
Atomically Flat

AbstractWe have grown films of (LaSr)MnO3 (LSMO) and (LaCa)MnO3 (LCMO) using atomic layer-by-layer molecular beam epitaxy (ALL-MBE). Depending on growth conditions, substrate lattice constant and the exact cation stoichiometry, the films are either pseudomorphic or strain relaxed. The pseudomorphic films show atomically flat surfaces, with a unit cell terrace structure that is a replica of that observed on the slightly vicinal substrates, while the strain relaxed films show bumpy surfaces correlated with a dislocation network. All films show tetragonal structure and exhibit anisotropic magnetoresistance, with a low field response, (1/R)(dR/dH) as large as 5 T−1.

Homo- and Hetero-Epitaxial Gallium Nitride Grown by Molecular Beam Epitaxy

1998 ◽  
Vol 537 ◽  
Author(s):  
C.T. Foxon ◽  
T.S. Cheng ◽  
D. Korakakis ◽  
S.V. Novikov ◽  
R.P. Campion ◽  
...  
Keyword(s):  
High Temperature ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Defect Density ◽  
Boundary Structure ◽  
Quantum Well Structures ◽  
Flat Surfaces ◽  
Grain Boundary Structure ◽  
Bulk Gan ◽  
Atomically Flat

AbstractVarious methods have been used to initiate growth by Molecular Beam Epitaxy (MBE) of GaN on sapphire, or other substrates, but there is always a problem with morphology and with a high defect density which results in the formation of a sub-grain boundary structure. We show that by using, homo-epitaxial growth on properly prepared bulk GaN substrates, combined with high temperature growth, we obtain a significant improvement in surface morphology. Growth at sufficiently high temperature leads to a rapid smoothing of the surface and to almost atomically flat surfaces over relatively large areas. Multi-Quantum Well structures grown on such GaN epitaxial films are dislocation free with abrupt interfaces.

scholarly journals Molecular Beam Epitaxy of High Quality InGaN Alloys Using Ammonia: Optical and Structural Properties

1999 ◽  
Vol 4 (S1) ◽  
pp. 333-338
Author(s):  
Nicolas Grandjean ◽  
Jean Massies ◽  
Mathieu Leroux ◽  
Marguerite Laügt ◽  
Philippe Vennéguès ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Quantum Wells ◽  
Structural Properties ◽  
Molecular Beam ◽  
Stokes Shift ◽  
Growth Conditions ◽  
Structural Quality ◽  
Luminescence Spectra ◽  
Near Band Edge ◽  
Flat Surfaces

The growth of InGaN layers was carried out by molecular beam epitaxy (MBE). The nitrogen precursor was ammonia. The optical and structural properties of the InGaN layers have been investigated by transmission electron microscopy (TEM), x-ray diffraction (XRD) and photoluminescence (PL). For optimized growth conditions, the PL spectrum of InGaN (x=0.1) alloy is narrow (FWHM ≤ 50 meV) and the Stokes shift measured by PL excitation is weak (<50 meV), i.e. near band edge transitions are observed. Under these conditions, flat surfaces can be obtained, and InGaN/GaN quantum wells (QWs) with sharp interfaces can be grown. On the other hand, when growth conditions depart from a narrow optimum window, the structural quality of the samples strongly degrade, whereas the luminescence spectra are dominated by deep levels, exhibiting a strong Stokes shift. MBE grown light emitting diodes (LEDs) using InGaN/GaN QWs have been fabricated. Their electroluminescence (EL) peaks at 440 nm at 300K.

scholarly journals Strain-induced structural transition in DyBa2Cu3O7−x films grown by atomic layer-by-layer molecular beam epitaxy

2020 ◽  
Vol 117 (7) ◽  
pp. 072601 ◽  
Author(s):  
D. Putzky ◽  
P. Radhakrishnan ◽  
Y. Wang ◽  
P. Wochner ◽  
G. Christiani ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Structural Transition ◽  
Atomic Layer ◽  
Layer By Layer

Effect of the Introduction of a MBE Buffer Layer on the Morphology of InSb Almbe Layers Grown on InP Substrates

1995 ◽  
Vol 399 ◽  
Author(s):  
J.C. Ferrer ◽  
A. Cornet ◽  
F. Peiró ◽  
J.R. Morante ◽  
T. Utzmeier ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Lattice Mismatch ◽  
Three Dimensional ◽  
Atomic Layer ◽  
Buffer Layers ◽  
Dislocation Network ◽  
Threading Dislocation ◽  
Large Lattice Mismatch ◽  
Inp Substrates

ABSTRACTIn this paper we report on the morphology of InSb layers grown by atomic layer molecular beam epitaxy (ALMBE) onto InP substrates at low temperatures (330<T<400°C), comparing the nature and densities of defects with those found in ALMBE InSb films grown over InSb/InP buffer layers grown by molecular beam epitaxy (MBE). The main types of defects for ALMBE direct layers are threading dislocations and stacking faults with similar defect densities along both á110ñ directions. The inclusion of the intermediate InSb/InP MBE grown buffer layers leads to lower threading dislocation densities but higher and anisotropic stacking fault distribution. Moreover, different types of three-dimensional defects appear, which are associated with pyramidal or truncated pyramidal hillocks on the surface. These defects, consisting in twins associations are originated at the InSb/InP MBE interface and they are induced by an anomalous growth of InSb layers. In all the cases, the strain caused by the large lattice mismatch is accommodated by means of a pure edge-type misfit dislocation network placed at the interface.

Molecular Beam Epitaxy of High Quality InGaN Alloys Using Ammonia: Optical and Structural Properties

1998 ◽  
Vol 537 ◽  
Author(s):  
Nicolas Grandjean ◽  
Jean Massies ◽  
Mathieu Leroux ◽  
Marguerite Laügt ◽  
Philippe Vennéguès ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Quantum Wells ◽  
Structural Properties ◽  
Molecular Beam ◽  
Stokes Shift ◽  
Growth Conditions ◽  
Structural Quality ◽  
Luminescence Spectra ◽  
Near Band Edge ◽  
Flat Surfaces

AbstractThe growth of InGaN layers was carried out by molecular beam epitaxy (MBE). The nitrogen precursor was ammonia. The optical and structural properties of the InGaN layers have been investigated by transmission electron microscopy (TEM), x-ray diffraction (XRD) and photoluminescence (PL). For optimized growth conditions, the PL spectrum of InGaN (x=0.1) alloy is narrow (FWHM ≤ 50 meV) and the Stokes shift measured by PL excitation is weak (<50 meV), i.e. near band edge transitions are observed. Under these conditions, flat surfaces can be obtained, and InGaN/GaN quantum wells (QWs) with sharp interfaces can be grown. On the other hand, when growth conditions depart from a narrow optimum window, the structural quality of the samples strongly degrade, whereas the luminescence spectra are dominated by deep levels, exhibiting a strong Stokes shift. MBE grown light emitting diodes (LEDs) using InGaN/GaN QWs have been fabricated. Their electroluminescence (EL) peaks at 440 nm at 300K.

Molecular Beam Epitaxy of PbTe/EuTe Superlattices

1992 ◽  
Vol 281 ◽  
Author(s):  
G. Springholz ◽  
G. Bauer
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Growth Conditions ◽  
High Energy ◽  
Small Range ◽  
Layer By Layer ◽  
Optimum Conditions ◽  
Heteroepitaxial Growth ◽  
X Ray Diffraction ◽  
Surface Reconstructions

ABSTRACTUsing reflection high energy electron diffraction (RHEED), the heteroepitaxy of EuTe on PbTe (111) by molecular beam epitaxy (MBE) was investigated. The resulting EuTe (111) surfaces exhibit different surface reconstructions corresponding to a Te-stabilized or a Eu-stabilized surface. We have observed perfect 2D layer-by-layer heteroepitaxial growth and RHEED intensity oscillations only for a small range of growth conditions. Using such optimum conditions, we have fabricated strained PbTe/EuTe superlattices with superior structural perfection, as shown by high resolution x-ray diffraction.

scholarly journals Homo- and Hetero-Epitaxial Gallium Nitride Grown by Molecular Beam Epitaxy

1999 ◽  
Vol 4 (S1) ◽  
pp. 484-489 ◽  
Author(s):  
C.T. Foxon ◽  
T.S. Cheng ◽  
D. Korakakis ◽  
S.V. Novikov ◽  
R.P. Campion ◽  
...  
Keyword(s):  
High Temperature ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Defect Density ◽  
Boundary Structure ◽  
Quantum Well Structures ◽  
Flat Surfaces ◽  
Grain Boundary Structure ◽  
Bulk Gan ◽  
Atomically Flat

Various methods have been used to initiate growth by Molecular Beam Epitaxy (MBE) of GaN on sapphire, or other substrates, but there is always a problem with morphology and with a high defect density which results in the formation of a sub-grain boundary structure. We show that by using, homo-epitaxial growth on properly prepared bulk GaN substrates, combined with high temperature growth, we obtain a significant improvement in surface morphology. Growth at sufficiently high temperature leads to a rapid smoothing of the surface and to almost atomically flat surfaces over relatively large areas. Multi-Quantum Well structures grown on such GaN epitaxial films are dislocation free with abrupt interfaces.

Atomic layer-by-layer molecular beam epitaxy of complex oxide films and heterostructures

2013 ◽  
pp. 509-528 ◽  
Author(s):  
James N. Eckstein ◽  
Mao Zheng ◽  
Xiaofang Zhai ◽  
Bruce Davidson ◽  
Maitri Warusawithana ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Oxide Films ◽  
Atomic Layer ◽  
Complex Oxide ◽  
Layer By Layer ◽  
Complex Oxide Films
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