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.

STRUCTURAL CHARACTERIZATION OF CO-PRECIPITATED Cd1-xZnxS:Cu CRYSTALS

2002 ◽  
Vol 16 (03) ◽  
pp. 481-496 ◽  
Author(s):  
ABDUL NAYEEM ◽  
K. YADAIAH ◽  
G. VAJRALINGAM ◽  
P. MAHESH ◽  
M. NAGABHOOSHANAM
Keyword(s):  
Grain Size ◽  
Dislocation Density ◽  
Internal Stress ◽  
Lattice Constant ◽  
Structural Characterization ◽  
Structural Parameters ◽  
Size Variation ◽  
Preferred Orientation ◽  
Average Internal Stress

Structural characterization of Cd 1-x Zn x S : Cu solid solutions were carried out with 0≤x≤1. XRD studies have revealed that the compounds are polycrystalline in nature having either Hexagonal (wurtzite) or Cubic (Zincblende) structure irrespective of their composition. Also the compounds have shown the most preferred reflections due to the plane [101] of CdS(H) and [111] of ZnS(C) in addition to other prominent reflections. The various structural parameters such as lattice constant, average internal stress, micro strain, dislocaion density, grain size, and preferred orientation were correlated with the composition. The lattice constant decreased linearly with the increase in Zn concentration. The sign of internal stress indicated elongational and compressional natures corresponding to hexagonal and cubic phases of CdS respectively. The variation of micro strain appeared to be conjugate when compared to grain size variation, and the variation of dislocation density with the composition showed a higher dislocation density till x=0.4 and then decreased till x=0.8 and then increased. The degree of preferred orientation in mixed Cd 1-x Zn x S : Cu crystals as observed by the maximum peak intensity of CdS(H) and ZnS(C) reflection showed that the degree of preferred orientation remained almost constant till x=0.6 and then increased. The results were explained on the basis of different phases of the compound and the defects related to Zn atoms.

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.

Density and Mechanical Strength of Ferrite for Inertial Gyroscope

2007 ◽  
Vol 546-549 ◽  
pp. 2265-2268
Author(s):  
Zhong Yu ◽  
Zhong Wen Lan ◽  
Ke Sun ◽  
Yu Chen
Keyword(s):  
Grain Size ◽  
Fracture Surface ◽  
Crystal Lattice ◽  
Lattice Constant ◽  
Bending Strength ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zn Ferrite ◽  
Electronic Microscope ◽  
Crystal Lattice Constant

The effects of NiO on density and mechanic strength of Mn-Zn ferrite used for inertial gyroscope were investigated by measurements of crystal lattice constant, Vickers hardness, bending strength. To investigate this further, powder of Mn-Zn ferrite was characterized by x-ray diffraction (XRD) and the fracture surface of Mn-Zn ferrite was checked by scanning electronic microscope (SEM). The investigation revealed that the substitution of Ni2+ modified crystal lattice constant and crystal grain size so that it caused crystal lattice constant of Mn-Zn ferrite to decline and crystal grain size to decrease, therefore it was useful to improve density and mechanic strength of Mn-Zn ferrite by this way. The results show that proper addition of NiO can bring higher density and more perfect mechanic strength of Mn-Zn ferrite used for inertial gyroscope.

Commensurability between vortex spacing and half the crystal lattice constant inNdBa2Cu3Oysingle crystals

2002 ◽  
Vol 66 (6) ◽  
Author(s):  
H. Küpfer ◽  
G. Ravikumar ◽  
Th. Wolf ◽  
A. A. Zhukov ◽  
A. Will ◽  
...  
Keyword(s):  
Crystal Lattice ◽  
Lattice Constant ◽  
Crystal Lattice Constant

SEM Characterization of Silicon Layers Grown on Carbon Foil

2009 ◽  
Vol 156-158 ◽  
pp. 473-476 ◽  
Author(s):  
Sergei K. Brantov ◽  
A.V. Eltzov ◽  
Olga V. Feklisova ◽  
Eugene B. Yakimov
Keyword(s):  
Dislocation Density ◽  
Defect Structure ◽  
Growth Direction ◽  
Carbon Foil ◽  
Twin Boundaries ◽  
X Ray ◽  
Electron Backscattering Diffraction ◽  
Silicon Ribbon ◽  
Selective Chemical

Characterization of defect structure in silicon ribbon grown on carbon foil has been carried out. The structure of grown Si layers and a dislocation density in these layers have been studied using selective chemical etching and the Electron Backscattering Diffraction. It is observed that the layers consist of rather large grains, the majority of which is elongated along the growth direction with a similar surface orientation and with a misorientation angle between neighboring grains of 60º. This means that such grains are separated by the (111) twin boundaries. The dislocation density in different grains is found to vary from 102 to 107cm-2. The energy dispersive X-Ray microanalysis has shown that some twin boundaries are enriched with carbon.

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