scholarly journals Characterization of Bulk 3C-SiC Single Crystals Grown on 4H-SiC by the CF-PVT Method

2006 ◽  
Vol 527-529 ◽  
pp. 99-102 ◽  
Author(s):  
Laurence Latu-Romain ◽  
Didier Chaussende ◽  
Carole Balloud ◽  
Sandrine Juillaguet ◽  
L. Rapenne ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Recent Work ◽  
Continuous Improvement ◽  
Crystal Quality ◽  
Multi Scale ◽  
Free Area

Because of the formation of DPB (Double Positioning Boundary) when starting from a hexagonal <0001> seed, DPB-free 3C-SiC single crystals have never been reported up to now. In a recent work we showed that, using adapted nucleation conditions, one could grow thick 3C-SiC single crystal almost free of DPB [1]. In this work we present the results of a multi-scale investigation of such crystals. Using birefringence microscopy, EBSD and HR-TEM, we find evidence of a continuous improvement of the crystal quality with increasing thickness in the most defected area, at the sample periphery. On the contrary, in the large DPB-free area, the SF density remains rather constant from the interface to the surface. The LTPL spectra collected at 5K on the upper part of samples present a nice resolution of multiple bound exciton features (up to m=5) which clearly shows the high (electronic) quality of our 3C-SiC material.

Growth and Characterization of Single Crystal Epitaxial CoGa on MBE Grown III-V Semiconductors

1988 ◽  
Vol 144 ◽  
Author(s):  
K. C. Garrison ◽  
C. J. Palmstrøm ◽  
R. A. Bartynski
Keyword(s):  
Substrate Temperature ◽  
Single Crystal ◽  
Single Crystals ◽  
Structural Quality ◽  
High Quality ◽  
Auger Analysis ◽  
Post Deposition

ABSTRACTWe have demonstrated growth of high quality single crystal CoGa films on Ga1−xAlxAs. These films were fabricated in-situ by codeposition of Co and Ga on MBE grown Ga1−xAlxAs(100) surfaces. The elemental composition of the films was determined using Rutherford Backscattering (RBS) and in-situ Auger analysis. The structural quality of the films' surfaces was studied using RHEED (during deposition) and LEED (post deposition). RBS channeling was used to determine the bulk crystalline quality of these films.For ∼500 Å CoGa films grown at ∼450°C substrate temperature, channeling data showed good quality epitaxial single crystals [χmin ∼7%] with minimal dechanneling at the interface.

scholarly journals Alignment facility and software for single-crystal time-of-flight neutron spectroscopy

2021 ◽  
Vol 54 (3) ◽  
pp. 957-962
Author(s):  
Zihao Liu ◽  
Harry Lane ◽  
Christopher D. Frost ◽  
Russell A. Ewings ◽  
J. Paul Attfield ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Neutron Source ◽  
Structural Characterization ◽  
Software Package ◽  
Neutron Spectroscopy ◽  
Spallation Neutron Source ◽  
Neutron Sources

An instrument and software algorithm are described for the purpose of characterization of large single crystals at the Alignment Facility of the ISIS spallation neutron source. A method for both characterizing the quality of the sample and aligning it in a particular scattering plane is introduced. A software package written for this instrument is presented, and its utility is demonstrated by way of an example of the structural characterization of large single crystals of Pb(Mg1/3Nb2/3)O3. Extensions and modifications of characterization instruments for future improved beamlines are suggested. It is hoped that this software will be used by the neutron community for pre-characterizing large single crystals for spectroscopy experiments and that in the future such a facility will be included as part of the spectroscopy suite at other spallation neutron sources.

Characterization of Natural and Synthesized FeTiO3 Crystals With RBS/PIXE/XRD

1997 ◽  
Vol 07 (03n04) ◽  
pp. 265-275
Author(s):  
R. Q. Zhang ◽  
S. Yamamoto ◽  
Z. N. Dai ◽  
K. Narumi ◽  
A. Miyashita ◽  
...  
Keyword(s):  
Single Crystals ◽  
Ion Beam ◽  
Pressure Control ◽  
Floating Zone ◽  
X Ray Diffraction ◽  
X Ray ◽  
Beam Analysis ◽  
Ppm Level

Natural FeTiO 3 (illuminate) and synthesized FeTiO 3, single crystals were characterized by Rutherford backscattering spectroscopy combined with channeling technique and particle-induced x-ray emission (RBS-C and PIXE). The results obtained by the ion beam analysis were supplemented by the x-ray diffraction analysis to identify the crystallographic phase. Oriented single crystals of synthesized FeTiO 3 were grown under the pressure control of CO 2 and H 2 mixture gas using a single-crystal floating zone technique. The crystal quality of synthesized FeTiO 3 single crystals could be improved by the thermal treatment but the exact pressure control is needed to avoid the precipitation of Fe 2 O 3 even during the annealing procedure. Natural FeTiO 3 contains several kinds of impurities such as Mn , Mg , Na and Si . The synthesized samples contain Al , Si and Na which are around 100 ppm level as impurities. The PBS-C results of the natural sample imply that Mn impurities occupy the Fe sublattice in FeTiO 3 or in mixed phase between ilmenite and hematite.

scholarly journals Growth and Characterization of Epsomite Single Crystals Doped with KCl from low Temperature Aqueous Solutions

1970 ◽  
Vol 33 (1) ◽  
pp. 47-54 ◽  
Author(s):  
S Ferdous ◽  
J Podder
Keyword(s):  
Aqueous Solutions ◽  
Single Crystals ◽  
Optical Quality ◽  
Dielectric Studies ◽  
Slow Cooling ◽  
Large Size ◽  
Isothermal Evaporation ◽  
Academy Of Sciences

Highly transparent and well faceted large size epsomite single crystals have been grown in pure form and doped with KCl from aqueous solutions by slow cooling and isothermal evaporation method. The optical quality of the epsomite improves on doping by KCl. Mass growth rates were found to increase with doping of lower concentrations of KCl and then decreases with the higher concentration of KCl. KCl doped epsomite crystal reveals that structures are slightly distorted due to adsorption of Cl- ion into the crystal lattice. DC conductivity along the growth axis for all of the grown crystals increases with temperature in the range of 25 to 70ºC and also increases with the KCl concentration. Dielectric constant is found to be almost independent of frequency up to range of 106Hz. The dielectric studies show the suitability of these grown crystals for optoelectronic applications. DOI: 10.3329/jbas.v33i1.2949 Journal of Bangladesh Academy of Sciences, Vol. 33, No. 1, 47-54, 2009

The Effect of Modified Crucible Design and Seed Attachment on SiC Crystal Grown by PVT

2013 ◽  
Vol 740-742 ◽  
pp. 77-80
Author(s):  
Jung Young Jung ◽  
Sang Il Lee ◽  
Mi Seon Park ◽  
Doe Hyung Lee ◽  
Hee Tae Lee ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Temperature Gradient ◽  
Single Crystals ◽  
Crystal Quality ◽  
Full Width ◽  
Half Maximum ◽  
Radial Temperature Gradient ◽  
Radial Temperature ◽  
Better Than

The present research was focused to investigate the effect of internal crucible design that influenced the 4H-SiC crystal growth onto a 6H-SiC seed by PVT method. The crucible design was modified to produce a uniform radial temperature gradient in the growth cell. The seed attachment was also modified with a use of polycrystalline SiC plate. The crystal quality of 4H-SiC single crystals grown in modified crucible and grown with modified seed attachment was revealed to be better than that of crystal grown in conventional crucible. The full width at half maximum (FWHM) values of grown SiC crystals in the conventional crucible, the modified seed attachment and the modified crucible were 285 arcsec, 134 arcsec and 128 arcsec, respectively. The micropipe density (MPD) of grown SiC crystals in the conventional crucible, the modified seed attachment and the modified crucible were 101ea/cm^2, 81ea/cm^2 and 42ea/cm^2, respectively.

scholarly journals Precursor Phenomena of Barium Titanate Single Crystals Grown Using a Solid-State Single Crystal Growth Method Studied with Inelastic Brillouin Light Scattering and Birefringence Measurements

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3171 ◽  
Author(s):  
Soo Han Oh ◽  
Jae-Hyeon Ko ◽  
Ho-Yong Lee ◽  
Iwona Lazar ◽  
Krystian Roleder
Keyword(s):  
Crystal Growth ◽  
Solid State ◽  
Barium Titanate ◽  
Single Crystal ◽  
Single Crystals ◽  
Melting Process ◽  
Point Of View ◽  
Crystal Quality ◽  
Cubic Phase ◽  
Growth Method

The nature of precursor phenomena in the paraelectric phase of ferroelectrics is one of the main questions to be resolved from a fundamental point of view. Barium titanate (BaTiO3) is one of the most representative perovskite-structured ferroelectrics intensively studied until now. The pretransitional behavior of BaTiO3 single crystal grown using a solid-state crystal growth (SSCG) method was investigated for the first time and compared to previous results. There is no melting process in the SSCG method, thus the crystal grown using a SSCG method have inherent higher levels of impurity and defect concentrations, which is a good candidate for investigating the effect of crystal quality on the precursor phenomena. The acoustic, dielectric, and piezoelectric properties, as well as birefringence, of the SSCG-grown BaTiO3 were examined over a wide temperature range. Especially, the acoustic phonon behavior was investigated in terms of Brillouin spectroscopy, which is a complementary technique to Raman spectroscopy. The obtained precursor anomalies of the SSCG-grown BaTiO3 in the cubic phase were similar to those of other single crystals, in particular, of high-quality single crystal grown by top-seeded solution growth method. These results clearly indicate that the observed precursor phenomena are common and intrinsic effect irrespective of the crystal quality.

scholarly journals Peculiar Structural Effects in Pure and Doped Functional Single Crystals of Complex Compositions

Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2451
Author(s):  
Galina Kuz’micheva ◽  
Irina Kaurova
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Functional Materials ◽  
Local Environment ◽  
Structural Effects ◽  
Local Structures ◽  
Annealing Conditions ◽  
Activator Ions

Results of a detailed structural characterization of nominally pure and doped single crystals of scheelite, eulytin, and perovskite families obtained by melt methods were considered and analyzed. The influence of growth and post-growth annealing conditions on actual compositions of crystals is shown. The reasons for the coloration of the crystals are explained. A change in crystal symmetry due to crystal–chemical and growth reasons is considered. The use of structural analysis and X-ray absorption spectroscopy is substantiated to reveal the role of activator ions in the formation of statistical and local structures, respectively. A relationship between the distribution of activator ions over crystallographic sites and photoluminescent parameters of materials is established, which allows selecting optimal systems for the application. The combined results of studying single-crystal compounds of other classes (huntite, sillenite, whitlockite, garnet, tetragonal bronzes) allow formulating and summarizing structural effects that appeared in the systems and caused by various factors and, in many cases, due to the local environment of cations. A principal difference in the structural behavior of solid solutions and doped compounds is shown. The methodology developed for single-crystal samples of complex compositions can be recommended for the systematic structural studies of functional materials of different compositions.

Optical and Electrical Properties of Cd Te Laser-Synthetized

1982 ◽  
Vol 13 ◽  
Author(s):  
L. Baufay ◽  
A. Pigeolet ◽  
R. Andrew ◽  
L.D. Laude
Keyword(s):  
Electrical Properties ◽  
Single Crystal ◽  
Electrical Characterization ◽  
Point Of View ◽  
Optical And Electrical Properties ◽  
Impurity States ◽  
Absorption Measurements ◽  
Forbidden Gap

ABSTRACTOptical and electrical characterization of CdTe synthetized by laser irradiationofamultilayer film of alternately Cd and Te is achieved. Optical absorption measurements evidence the good quality of these films and show that they have behaviour comparable to the single crystal. The influence of the irradiation conditions on the electrical properties of such CdTe films is discussed; they are compared to single crystal from the point of view of resistivity. It is shown that it is possible to prepare by this means samples devoid of impurity states in the middle of the forbidden gap. Finally, the ohmicity of Au, Al, Cr, ITO and non irradiated Cd/Te sandwich contacts is tested.

The Last Missing Member of the AE2[BN2]Cl Series – Synthesis, Structural and Spectroscopic Characterization of Ba2[BN2]Cl

2008 ◽  
Vol 63 (5) ◽  
pp. 525-529 ◽  
Author(s):  
Olaf Reckeweg ◽  
Jesse Reiherzer ◽  
Armin Schulz ◽  
Francis J. DiSalvo
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Single Crystals ◽  
Structure Determination ◽  
Title Compound ◽  
Spectroscopic Characterization ◽  
X Ray ◽  
Fundamental Frequencies ◽  
Raman And Ir Spectra

Pale grey-blue, transparent single crystals of Ba2[BN2]Cl (I4132 (no. 214), a = 1462.88(1) pm, Z = 24) are obtained by the reaction of Ba, BaCl2, BN and NaN3 in arc-welded Ta ampoules at 1200 K. The crystal structure was determined by single crystal X-ray structure analysis. The Raman and IR spectra of the title compound show the expected fundamental frequencies (νs = 1038; νas = 1969 and 2087; δ = 616 / 636 cm−1) for a nitridoborate unit with D∞h symmetry. The [N-B-N] structure obtained by X-ray single crystal structure determination corroborates this finding within the standard deviations of the measurement with d(B-N) = 132.3(8) pm and ∡ (N-B-N) = 178.5(13)°. Our results compare well to the data reported for cubic and orthorhombic Ba3[BN2]2 as well as to the isotypic compound Ba2[BN2]Br.

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