scholarly journals Characterization of crystal lattice constant and strain of GaN epilayers with different AlxGa1－xN and AlN buffer layers grown on Si(111)

2006 ◽  
Vol 55 (6) ◽  
pp. 2977
Author(s):  
Ding Zhi-Bo ◽  
Yao Shu-De ◽  
Wang Kun ◽  
Cheng Kai
Keyword(s):  
Crystal Lattice ◽  
Lattice Constant ◽  
Buffer Layers ◽  
Aln Buffer ◽  
Crystal Lattice Constant

Characterization of crystal lattice constant and dislocation density of crack-free GaN films grown on Si(111)

2010 ◽  
Vol 257 (4) ◽  
pp. 1161-1165 ◽  
Author(s):  
Jijun Xiong ◽  
Jianjun Tang ◽  
Ting Liang ◽  
Yong Wang ◽  
Chenyang Xue ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Crystal Lattice ◽  
Lattice Constant ◽  
Crystal Lattice Constant

scholarly journals Characterization of The Volcanic Rocks of Mount Sinabung, Simacem Village, Karo Regency, Conducted With XRD, SEM-EDX

2019 ◽  
Vol 1 (1) ◽  
pp. 1-5
Author(s):  
Perdinan Sinuhaji
Keyword(s):  
Crystal Lattice ◽  
Lattice Constant ◽  
Elemental Analysis ◽  
Volcanic Rocks ◽  
Lattice Constants ◽  
Crystal System ◽  
Tetragonal Crystals ◽  
Hexagonal Crystals ◽  
Crystal Lattice Constant

The study of volcanic rocks characterization of Sinabung Volcano erupted on September 15, 2017. The volcanic rocks crystal system was performed with XRD, elemental analysis and microstructure with SEM-EDX. Volcanic rocks contain: Anorthite phase 87,11 (wt%), Triclinic crystal, lattice constant, a = 8.1742 Å, b = 12,844 Å, c = 14,204 Å; Quartz phase 2.26%, Hexagonal crystals, lattice constants, a = 4,799 Å, b = 4,799 Å, c = 5,379 Å; Cristobalite phase 7.72 (wt%), Tetragonal crystals, lattice constants a = 4,970 Å, b = 6,990 Å, c = 6,998 Å; Alunite phase 2.91 (wt%), Hexagonal crystals, lattice constants, a = 6,990 Å, b = 6,990 Å, c = 17,282 Å.

scholarly journals The Rise of (Chiral) 3D Mechanical Metamaterials

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3527 ◽  
Author(s):  
Janet Reinbold ◽  
Tobias Frenzel ◽  
Alexander Münchinger ◽  
Martin Wegener
Keyword(s):  
Crystal Lattice ◽  
Lattice Constant ◽  
Linear Polarization ◽  
Three Dimensional ◽  
Future Perspectives ◽  
Special Issue ◽  
Polarization Rotation ◽  
Mechanical Metamaterials ◽  
The One ◽  
Crystal Lattice Constant

On the occasion of this special issue, we start by briefly outlining some of the history and future perspectives of the field of 3D metamaterials in general and 3D mechanical metamaterials in particular. Next, in the spirit of a specific example, we present our original numerical as well as experimental results on the phenomenon of acoustical activity, the mechanical counterpart of optical activity. We consider a three-dimensional chiral cubic mechanical metamaterial architecture that is different from the one that we have investigated in recent early experiments. We find even larger linear-polarization rotation angles per metamaterial crystal lattice constant than previously and a slower decrease of the effects towards the bulk limit.

Growth and Characterization of GaN on Si(111)

1994 ◽  
Vol 339 ◽  
Author(s):  
A. Ohtani ◽  
K. S. Stevens ◽  
R. Beresford
Keyword(s):  
Growth Temperature ◽  
Electron Cyclotron Resonance ◽  
Microwave Plasma ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
Ion Density ◽  
Nitrogen Ion ◽  
Gan On Si ◽  
Aln Buffer

ABSTRACTWurtzite GaN films on AlN buffer layers were grown on Si (111) by electron cyclotron resonance microwave plasma assisted MBE (ECR-MBE). High resolution x-ray diffraction studies indicate that the mosaic disorder decreases with increasing growth temperature. The grain size is related to the growth temperature. The best (0002) diffraction peak full width at half maximum was 22 min. for a film 1.7 μm thick. Prominent exciton luminescence is observed at 3.46 eV at 10 K.The plasma I-V characteristics were measured with a Langmuir probe near the growth position. The nitrogen ion density has been extracted from the data, and is a strong function of the N2 flow rate, the microwave power and the aperture size of the ECR source. The crystal quality of AlN is strongly affected by the plasma conditions.

Growth and Characterization of AlN and GaN Thin Films Deposited on Si(111) Substrates Containing a Very Thin Al Layer

2003 ◽  
Vol 798 ◽  
Author(s):  
Zachary J. Reitmeier ◽  
Robert F. Davis
Keyword(s):  
Flow Time ◽  
Buffer Layers ◽  
Nucleation Density ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Aln Buffer ◽  
Peak Widths

ABSTRACTAlN films and GaN films with AlN buffer layers were deposited via metalorganic vapor phase epitaxy on Si(111) substrates previously exposed to trimethylaluminum for increasing times. Atomic force microscopy (AFM) was used to determine the influence of Al pre-flow time on the nucleation and surface morphology of the AlN and GaN films. When preceded by a 10 second Al pre-flow, AlN films feature an increased and more uniform nucleation density as compared to films deposited without Al pre-flows. Ten second Al pre-flows were also found to result in a reduction of the RMS roughness for 100 nm thick AlN films from 3.6 nm to 1.0 nm. AFM of 0.5 μm thick GaN films deposited on AlN buffers with varying pre-flow times showed reduced roughness and decreased pit density when using Al pre-flows of 10 or 20 seconds. High resolution x-ray diffraction of the GaN films showed a reduction in the average full-width halfmaximum (FWHM) of the GaN (00.2) reflection from 1076 arcsec to 914 arcsec when the AlN buffer layer was initiated with a 10 second Al pre-flow. Increasing the pre-flow time to 20 seconds and 30 seconds resulted in average (00.2) FWHM values of 925 arcsec and 928 arcsec, respectively. Similar behavior of the peak widths was observed for the (30.2) and (10.3) reflections when the pre-flow times were varied from 0 to 30 seconds.

Atomic scale characterization of GaInN/GaN layers grown on sapphire substrates with low-temperature deposited AlN buffer layers

2002 ◽  
Vol 237-239 ◽  
pp. 1133-1138 ◽  
Author(s):  
M. Tabuchi ◽  
H. Kyouzu ◽  
Y. Takeda ◽  
S. Yamaguchi ◽  
H. Amano ◽  
...  
Keyword(s):  
Low Temperature ◽  
Atomic Scale ◽  
Buffer Layers ◽  
Sapphire Substrates ◽  
Scale Characterization ◽  
Aln Buffer

scholarly journals Исследование характеристик сверхрешетки InGaAs/InAlGaAs для вертикально-излучающих лазеров спектрального диапазона 1300 nm

2021 ◽  
Vol 91 (12) ◽  
pp. 2008
Author(s):  
С.А. Блохин ◽  
А.В. Бабичев ◽  
А.Г. Гладышев ◽  
Л.Я. Карачинский ◽  
И.И. Новиков ◽  
...  
Keyword(s):  
Crystal Lattice ◽  
Quantum Wells ◽  
Lattice Constant ◽  
Current Density ◽  
Lattice Mismatch ◽  
Active Regions ◽  
Cavity Surface ◽  
Excitation Power Density ◽  
Emitting Lasers ◽  
Crystal Lattice Constant

X-ray structural analysis and photoluminescence spectroscopy techniques were used to study heterostructures based on InGaAs/InAlGaAs superlattice for active regions of 1300 nm range lasers grown by molecular beam epitaxy. It is shown that the grown heterostructures have a high crystal quality. The perpendicular lattice mismatch of the average crystal lattice constant of the InGaAs/InAlGaAs superlattice with respect to the crystal lattice constant of the InP substrate is estimated at ~ +0.01%. An analysis of the photoluminescence spectra made it possible to conclude that the contribution of Auger recombination is insignificant in the studied range of excitation power density. Studies of vertical-cavity surface-emitting lasers with an active region based on the InGaAs/InAlGaAs superlattice made it possible to estimate the gain coefficient at a level of 650 cm-1 for the standard logarithmic approximation of the dependence of the gain on the current density. The transparency current density of the laser was ~150 А/cm2, which is comparable to the record low values for the case of highly strained InGaAs-GaAs and InGaAsN-GaAs quantum wells in the spectral ranges of 1200 nm and 1300 nm, respectively.

Characterization of ALN buffer layers on (0001)-sapphire substrates

1998 ◽  
Vol 189-190 ◽  
pp. 282-286 ◽  
Author(s):  
Yves-Matthieu Le Vaillant ◽  
René Bisaro ◽  
Jean Olivier ◽  
Olivier Durand ◽  
Jean-Yves Duboz ◽  
...  
Keyword(s):  
Buffer Layers ◽  
Sapphire Substrates ◽  
Aln Buffer

Structure characterization of AlN buffer layers grown on (0001) sapphire by magnetron sputter epitaxy

2002 ◽  
Vol 244 (1) ◽  
pp. 1-5 ◽  
Author(s):  
H Tang ◽  
J.B Webb ◽  
S Moisa ◽  
J.A Bardwell ◽  
S Rolfe
Keyword(s):  
Structure Characterization ◽  
Buffer Layers ◽  
Magnetron Sputter ◽  
Aln Buffer
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