Epitaxial Growth of (111) TbFe2 by Sputter Deposition

1995 ◽  
Vol 384 ◽  
Author(s):  
C.T. Wang ◽  
R.M. Osgood ◽  
R.L. White ◽  
B.M. Clemens
Keyword(s):  
Rutherford Backscattering Spectrometry ◽  
Compressive Strain ◽  
Buffer Layers ◽  
Stress And Strain ◽  
X Ray ◽  
Sapphire Substrates ◽  
Magnetoelastic Energy ◽  
Out Of Plane ◽  
Magnetization Orientation ◽  
Theoretical Considerations

ABSTRACTThe effect of in-plane strain in (111)-oriented epitaxial TbFe2 films on the magnetization orientations was studied. Magnetocrystalline anisotropy, shape anisotropy, and magnetoelastic energy were calculated to determine the magnetization orientation in the presence of various in-plane strains. Theoretical considerations indicate that a compressive strain smaller than -0.065% can induce an out-of-plane magnetization. DC magnetron sputtering from Tb and Fe elemental targets was used to grow 50, 100, 200, and 400 Å thick epitaxial TbFe2(111) films at 600°C on (110)-oriented sapphire substrates with 1000 Å thick epitaxial Mo(110) buffer layers. The growth rate of the TbFe2(111) films was 1.44 Å/sec. X-ray diffractometry, Rutherford backscattering spectrometry, and vibrating sample magnetometry were used to characterize the crystal structure, epitaxial orientation, composition, stress and strain state, and magnetic properties of the TbFe2 films. The TbFe2(111) films were epitaxial with twins rotated by 60° and were in tensile strain states with the resulting in-plane magnetization.

Pulsed Laser Deposition of Epitaxial LiNbO3 Films on Sapphire Substrates Using a Single Crystal Targets

1994 ◽  
Vol 361 ◽  
Author(s):  
See-Hyung Lee ◽  
Tae W. Noh ◽  
Jai-Hyung Lee ◽  
Young-Gi Kim
Keyword(s):  
Single Crystal ◽  
Pulsed Laser Deposition ◽  
Pole Figure ◽  
Oxygen Pressure ◽  
Rutherford Backscattering Spectrometry ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
X Ray ◽  
Sapphire Substrates ◽  
Crystallographic Orientations

ABSTRACTPulsed laser deposition was used to grow epitaxial LiNbO3 films on sapphire(0001) substrates with a single crystal LiNbO3 target. Using deposition temperatures below 450 °C, LiNbO3 films with correct stoichiometry could be grown without using Li-rich targets. Rutherford backscattering spectrometry measurements showed that the oxygen to niobium ratio is 3.00 ± 0.15 to 1.00. It was also found that the crystallographic orientations of the LiNbO3 films could be controlled by adjusting the oxygen pressure during deposition. An x-ray pole figure shows that epitaxial LiNbO3 films were grown on sapphire(0001), but with twin boundaries.

Epitaxial Growth of Cerium Oxide Buffer Layers on MgO, YSZ and Sapphire Substrates

2000 ◽  
Vol 619 ◽  
Author(s):  
A. Thorley ◽  
S. Gnanarajan ◽  
A. Katsaros ◽  
N. Savvides
Keyword(s):  
Thin Films ◽  
Epitaxial Growth ◽  
Buffer Layers ◽  
Metal Target ◽  
X Ray Diffraction ◽  
Dc Magnetron Sputtering ◽  
X Ray ◽  
Sapphire Substrates ◽  
Pole Figures ◽  
Biaxial Alignment

ABSTRACTWe studied the epitaxial growth of CeO2 thin films deposited onto MgO(100), YSZ(100) and Al2O3(1102 ) (r-plane sapphire) substrates by reactive dc magnetron sputtering of a Ce metal target in an Ar/O2 plasma. The crystalline quality and biaxial alignment of the films was determined using x-ray diffraction techniques (θ-2θ, ω-scans, pole figures, ø-scans). The CeO2/MgO(100) and CeO2/Al2O3(1102) epitaxy was evident at 600°C and developed to nearly perfect biaxial alignment at 850°C with Δø = 5° and 9° respectively. The CeO2/YSZ (100) epitaxy occurred below 300°C while deposition at ≥ 650°C led to single-crystal quality CeO2 films with Δø = 0.2°.

Non-Polar GaN/AlN Superlattices on A-plane AlN (500nm) Buffer Layers Grown by RF-MBE

2004 ◽  
Vol 831 ◽  
Author(s):  
Takayuki Morita ◽  
Akihiko Kikuchi ◽  
Katsumi Kishino
Keyword(s):  
Molecular Beam ◽  
Growth Conditions ◽  
Buffer Layers ◽  
Structural Quality ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sapphire Substrates ◽  
Frequency Plasma ◽  
Diffraction Peaks ◽  
Rich Side

ABSTRACTThe growth conditions of A-plane AlN and GaN epitaxial layers by radio-frequency plasma assisted molecular beam epitaxy on R-plane sapphire substrates were investigated. The growth temperature and V/III supply ratio dependency on structural quality and surface roughness was described. The optimum V/III ratio for A-plane GaN and AlN layers was shifted to nitrogen rich side compared to the C-plane layers. A-plane GaN/AlN superlattices (SLs) were also grown on R-plane sapphire substrates. The X-ray diffraction peaks from a primary and a 1st satellite were observed. From a comparison of low temperature photoluminescence peak wavelength between A-plane and C-plane SLs, the built-in electrostatic field originated from spontaneous and piezoelectric polarization is negligible for A-plane SLs.

Growth of quaternary AlInGaN/GaN Heterostructures by Plasma Induced Molecular Beam Epitaxy with high In Concentration

2000 ◽  
Vol 639 ◽  
Author(s):  
A. P. Lima ◽  
C. R. Miskys ◽  
L. Görgens ◽  
O. Ambacher ◽  
A. Wenzel ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Substrate Temperature ◽  
Molecular Beam ◽  
Quaternary Alloy ◽  
Buffer Layers ◽  
Lattice Match ◽  
X Ray ◽  
Lattice Constants ◽  
Sapphire Substrates ◽  
N Fluxes

ABSTRACTGrowth of AlInGaN/GaN heterostructures on sapphire substrates was achieved by plasma induced molecular beam epitaxy. Different alloy compositions were obtained by varying the growth temperature with constant Al, In, Ga and N fluxes. The In content in the alloy, measured by Rutherford Backscattering Spectroscopy, increased from 0.4% to 14.5% when the substrate temperature was decreased from 775 to 665°C. X-Ray reciprocal space maps of asymmetric AlInGaN (2.05) reflexes were used to measure the lattice constants and to verify the lattice match between the quaternary alloy and the GaN buffer layers.

Characterisation of YSZ Layers Deposited on Y2O3 Buffered Textured Tapes for Coated Conductors

2014 ◽  
Vol 787 ◽  
pp. 425-430
Author(s):  
Yu Dong Xia ◽  
Jie Xiong ◽  
Fei Zhang ◽  
Yan Xue ◽  
Kai Hu ◽  
...  
Keyword(s):  
Coated Conductors ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
X Ray ◽  
Atomic Force ◽  
Deposition Parameters ◽  
Out Of Plane ◽  
Textured Tapes ◽  
Moving Speed

Yttria-stabilized zirconia (YSZ) films were deposited on Y2O3/Ni-5at.%W substrates serving as the barrier layers for coated conductors by reel-to-reel direct-current (D.C.) magnetron reactive sputtering. The deposition parameters, such as the substrate temperature and tape moving speed, were systematically investigated. X-ray diffraction analysis confirmed that optimized YSZ/Y2O3buffer layers showed excellent in-plane and out-of-plane textures. Atomic force microscope revealed a smooth, dense and crack-free surface. The subsequent CeO2cap layer and 1μm-thick YBa2Cu3O7-δfilm sequentially prepared, showing the critical current densityJcunder 77K, self-field of 1.4MA/cm2.

Nucleation and Growth of Gallium Nitride Films on Si and Sapphire Substrates Using Buffer Layers

1996 ◽  
Vol 423 ◽  
Author(s):  
N. R. Perkins ◽  
M. N. Horton ◽  
D. Zhi ◽  
R. J. Matyi ◽  
Z. Z. Bandic ◽  
...  
Keyword(s):  
Gallium Nitride ◽  
Defect Density ◽  
Deep Level ◽  
Growth Front ◽  
Nucleation And Growth ◽  
Buffer Layers ◽  
Initial Growth ◽  
X Ray ◽  
Sapphire Substrates ◽  
Aln Buffer

AbstractWe have investigated the nucleation and growth of gallium nitride (GaN) films on silicon and sapphire substrates using halide vapor phase epitaxy (HVPE). GaN growth was carried out on bare Si and sapphire surfaces, as well as on MOVPE-grown GaN buffer layers. HVPE growth on MOVPE GaN/AlN buffer layers results in lower defect densities as determined by x-ray than growth directly on sapphire. HVPE GaN films grown directly on sapphire exhibit strong near-edge photoluminescence, a pronounced lack of deep level-based luminescence, and x-ray FWHM values of 16 arcsec by an x-ray θ-2θ scan. The crystallinity of GaN films on sapphire is dominated by the presence of rotational misorientation domains, as measured by xray ω-scan diffractometry, which tend to decrease with increasing thickness or with the use of a homoepitaxial MOVPE buffer layer. The effect of increasing film thickness on the defect density of the epilayer was studied. In contrast, the HVPE growth of nitride films directly on silicon is complicated by mechanisms involving the formation of silicon nitrides and oxides at the initial growth front.

Structural Anisotropy and Optical Properties of Nonpolar a-Plane GaN Epitaxial Layers

2015 ◽  
Vol 15 (10) ◽  
pp. 7787-7790 ◽  
Author(s):  
Yong Gon Seo ◽  
Sun Hye Shin ◽  
Doo Soo Kim ◽  
Hyung-Do Yoon ◽  
Sung-Min Hwang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Compressive Strain ◽  
Dangling Bond ◽  
Structural Anisotropy ◽  
X Ray ◽  
Sapphire Substrates ◽  
Pl Intensity ◽  
Peak Widths ◽  
Gan Film ◽  
Specific Crystal Orientation

In-plane structural anisotropy is characteristic of nonpolar (1120) a-plane GaN (a-GaN) films grown on r-plane sapphire substrates. The anisotropic peak broadenings of X-ray rocking curves (XRCs) are clearly observed with M- or W-shaped dependence on the azimuth angles. We investigated the optical properties of both M- and W-shaped a-GaN samples with room and low-temperature photoluminescence (PL) measurements. The W-shaped a-GaN film showed higher PL intensity and more compressive strain compared to the M-shaped a-GaN film, whereas the XRC peak widths of the M-shaped a-GaN film on the azimuth angles are lower than those of W-shaped specimens, indicating that better crystalline quality was obtained. We speculate that the PL intensity and strain state of a-GaN layers may be more influenced by the crystallinity of a specific crystal orientation or direction, especially along the m-axis as opposed to the c-axis. This occurrence is most likely due to anisotropic defect distributions, resulting from differences in dangling bond densities of (0001) and {1-100} facets.

Epitaxial Buffer Layers on (012) Sapphire and (100) SrTiO3 for the Integration of YBa2Cu3Ox in Microwave Devices and Squids

1992 ◽  
Vol 275 ◽  
Author(s):  
H. Schmidt ◽  
G. Vollnhals ◽  
G. Gieres ◽  
W. Wersing ◽  
H. Kinder
Keyword(s):  
Grain Boundaries ◽  
Epitaxial Growth ◽  
Pole Figure ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Layer Sequence ◽  
Ion Channeling ◽  
Sapphire Substrates ◽  
Microwave Applications

ABSTRACTThe epitaxial growth of YBa2Cu3Ox films on sapphire for microwave applications requires epitaxial buffer layers hindering interdiffusion. Therefore the epitaxial growth of YSZ, the layer sequence Y2O3/YSZ, and Y2O3 on (012) sapphire was examined. In addition the growth of MgO and srTiO3 on sapphire substrates and the growth of MgO and CeO2 on SrTiO3 substrates was studied by X-ray diffraction, X-ray pole figure measurement and RBS-ion channeling. With a combination of these buffer layers bi-epitaxial grain boundaries in YBa2Cu3Ox films can be fabricated in future.

Bowing Parameter of AlxGa1-xN

2002 ◽  
Vol 722 ◽  
Author(s):  
Feng Yun ◽  
Michael A. Reshchikov ◽  
Lei He ◽  
Thomas King ◽  
M. Zafar Iqbal ◽  
...  
Keyword(s):  
Entire Range ◽  
Rutherford Backscattering Spectrometry ◽  
Parameter Determination ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sapphire Substrates ◽  
Bowing Parameter ◽  
Large Dispersion ◽  
Parameter Values ◽  
Secondary Ion

AbstractAlxGa1-xN samples covering the entire range of alloy compositions, 0≤x≤1, were grown by plasma-assisted MBE on c-plane sapphire substrates. The aluminum mole fraction was determined, by three different techniques, namely, x-ray diffraction, secondary ion mass spectroscopy, and Rutherford backscattering spectrometry. The energy bandgaps of the alloys were obtained from low temperature reflectance spectra. The data lead to a bowing parameter of b=1.0 eV in relating the bandgap of the AlxGa1-xN alloy to its chemical composition. A discussion of bowing parameter determination is presented along with possible causes for the large dispersion in previously reported bowing parameter values.

Effect of Growth Conditions and Buffer Layers on the Metal-Insulator Transition in V2O3 Thin Films

1995 ◽  
Vol 401 ◽  
Author(s):  
H. Schuler ◽  
G. Weissmann ◽  
C. Renner ◽  
S. Six ◽  
S. Klimm ◽  
...  
Keyword(s):  
Thin Films ◽  
Growth Conditions ◽  
Buffer Layers ◽  
Infrared Transmission ◽  
X Ray Diffraction ◽  
Metal Insulator ◽  
X Ray ◽  
Sapphire Substrates ◽  
Hall Effect Measurements ◽  
Mi Transition

AbstractThin films of V2O3 with thickness from 20 to 450 nm were deposited on (0001) oriented sapphire substrates by reactive e-beam evaporation. LEED, x-ray diffraction and AFM studies show highly oriented grains with a lateral size of 50 to 800 nm, dependent on substrate temperature and deposition rate. The films were characterized by optical and infrared transmission, electrical resistance and Hall effect measurements. Films grown directly on the Al2O3-substrate show a very broad metal-insulator (MI) transition as a function of temperature. The width of the transition decreases with increasing film thickness. The insertion of Cr2O3 buffer layers decreases the transition width by a further factor of three. The electronic properties of the films can be drastically influenced by the growth conditions.

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