Effect of doping on crystalline quality of rubidium titanyl phosphate (RTP) crystals grown by the TSSG method

2014 ◽  
Vol 1698 ◽  
Author(s):  
Jianqiu Guo ◽  
Balaji Raghothamachar ◽  
Michael Dudley ◽  
Joan J. Carvajal ◽  
Ali Butt ◽  
...  
Keyword(s):  
Growth Process ◽  
Solution Growth ◽  
Crystalline Quality ◽  
Defect Structures ◽  
Growth Sector ◽  
High Quality ◽  
X Ray ◽  
Linear Defects ◽  
Top Seeded Solution Growth

ABSTRACTDefect structures in Rubidium Titanyl Phosphate (RTP) crystals (non-doped and doped) grown by the Top Seeded Solution Growth (TSSG) method were characterized using Synchrotron White Beam X-ray Topography. Main defects observed in non-doped crystals are growth sector boundaries while both growth sector boundaries and growth striations are observed in the Nb single doped and (Nb,Yb)-codoped crystals with relatively few linear defects such as dislocations. Results show that the overall crystalline quality is lowered as more doping elements are incorporated. Details of defect distributions are correlated with the growth process to facilitate high quality growth of doped RTP.

Synchrotron X-Ray Topographic Study of Defects in High Quality, Flux Grown Ktiopo4 Single Crystals

1993 ◽  
Vol 307 ◽  
Author(s):  
S. Wang ◽  
M. Dudley ◽  
L. K. Cheng ◽  
J. D. Bierlein
Keyword(s):  
Detailed Analysis ◽  
Single Crystals ◽  
Domain Walls ◽  
Defect Structures ◽  
Growth Sector ◽  
High Quality ◽  
X Ray ◽  
Free Region ◽  
Ferroelectric Domains ◽  
Section Topography

ABSTRACTDefect structures in large, high quality flux-grown KTP single crystals have been studied by using synchrotron white beam X-ray topography. Growth dislocations, inclusions, growth sector boundaries, growth bands and surface micro-scratches were imaged. A number of planar defects in the dislocation-free region are imaged and determined to be inversion twin lamellae (lamellar ferroelectric domains) which have never been previously reported in KTP crystals. These inversion twin lamellae were also studied by section topography. Detailed analysis of observed contrast revealed that the domain walls bounding the lamellae are faulted with a fault vector of ½[0±1±1]. This fault vector seems to be consistent with the atomic structure of KTP. A detailed analysis is presented and discussed.

Crystalline Quality Evaluation of 6H-SiC Bulk Crystals Grown from Si-Ti-C Ternary Solution

2005 ◽  
Vol 483-485 ◽  
pp. 13-16 ◽  
Author(s):  
Kazuhiko Kusunoki ◽  
Kazuhito Kamei ◽  
Y. Ueda ◽  
S. Naga ◽  
Y. Ito ◽  
...  
Keyword(s):  
Grown Crystal ◽  
Seed Crystal ◽  
Solution Growth ◽  
Crystalline Quality ◽  
Ternary Solution ◽  
Bulk Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Koh Etching

The growth of 6H-SiC crystal from Si-Ti-C ternary solution was conducted under the temperature gradient and the crystalline quality evaluations of the grown crystals were carried out. 6H-SiC(0001) on-axis pvt-grown crystal was used as a seed crystal. Micropipes in the seed crystal were terminated during the solution growth and 28mm􀊷28mm self-standing micropipe-free SiC crystals were obtained. The quality of the grown crystals was investigated by SIMS, high-resolution x-ray diffraction and molten KOH etching. The content of residual impurities in the SiC were very low. The X-ray 􀐢-rocking curves of the solution grown SiC showed single peak with high peak intensity ,while that of the seed crystal showed several peaks due to the misoriented domains. Moreover, it was found that the number of etch-pit in the grown crystal is much less than that in the seed crystal and it decreases with the increase of the growth thickness. These results indicate that the crystalline quality of grown crystal was significantly improved during the solution growth.

scholarly journals Investigation of the Heteroepitaxial Process Optimization of Ge Layers on Si (001) by RPCVD

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 928
Author(s):  
Yong Du ◽  
Zhenzhen Kong ◽  
Muhammet Toprak ◽  
Guilei Wang ◽  
Yuanhao Miao ◽  
...  
Keyword(s):  
High Temperature ◽  
Buffer Layer ◽  
Layer Thickness ◽  
Growth Temperature ◽  
Crystalline Quality ◽  
Initial Growth ◽  
Two Dimensional ◽  
High Quality ◽  
Reduced Pressure

This work presents the growth of high-quality Ge epilayers on Si (001) substrates using a reduced pressure chemical vapor deposition (RPCVD) chamber. Based on the initial nucleation, a low temperature high temperature (LT-HT) two-step approach, we systematically investigate the nucleation time and surface topography, influence of a LT-Ge buffer layer thickness, a HT-Ge growth temperature, layer thickness, and high temperature thermal treatment on the morphological and crystalline quality of the Ge epilayers. It is also a unique study in the initial growth of Ge epitaxy; the start point of the experiments includes Stranski–Krastanov mode in which the Ge wet layer is initially formed and later the growth is developed to form nuclides. Afterwards, a two-dimensional Ge layer is formed from the coalescing of the nuclides. The evolution of the strain from the beginning stage of the growth up to the full Ge layer has been investigated. Material characterization results show that Ge epilayer with 400 nm LT-Ge buffer layer features at least the root mean square (RMS) value and it’s threading dislocation density (TDD) decreases by a factor of 2. In view of the 400 nm LT-Ge buffer layer, the 1000 nm Ge epilayer with HT-Ge growth temperature of 650 °C showed the best material quality, which is conducive to the merging of the crystals into a connected structure eventually forming a continuous and two-dimensional film. After increasing the thickness of Ge layer from 900 nm to 2000 nm, Ge surface roughness decreased first and then increased slowly (the RMS value for 1400 nm Ge layer was 0.81 nm). Finally, a high-temperature annealing process was carried out and high-quality Ge layer was obtained (TDD=2.78 × 107 cm−2). In addition, room temperature strong photoluminescence (PL) peak intensity and narrow full width at half maximum (11 meV) spectra further confirm the high crystalline quality of the Ge layer manufactured by this optimized process. This work highlights the inducing, increasing, and relaxing of the strain in the Ge buffer and the signature of the defect formation.

scholarly journals Short-pulse laser-driven x-ray radiography

2016 ◽  
Vol 4 ◽  
Author(s):  
E. Brambrink ◽  
S. Baton ◽  
M. Koenig ◽  
R. Yurchak ◽  
N. Bidaut ◽  
...  
Keyword(s):  
Pulse Laser ◽  
Short Pulse ◽  
Incident Angle ◽  
Laboratory Astrophysics ◽  
Signal To Noise ◽  
High Quality ◽  
X Ray ◽  
Short Pulse Laser ◽  
Short Pulse Lasers

We have developed a new radiography setup with a short-pulse laser-driven x-ray source. Using a radiography axis perpendicular to both long- and short-pulse lasers allowed optimizing the incident angle of the short-pulse laser on the x-ray source target. The setup has been tested with various x-ray source target materials and different laser wavelengths. Signal to noise ratios are presented as well as achieved spatial resolutions. The high quality of our technique is illustrated on a plasma flow radiograph obtained during a laboratory astrophysics experiment on POLARs.

Growth defects and infrared spectra analysis of CePO4single crystals

2005 ◽  
Vol 38 (4) ◽  
pp. 675-677 ◽  
Author(s):  
Kunpeng Wang ◽  
Jianxiu Zhang ◽  
Jiyang Wang ◽  
Changshui Fang ◽  
Wentao Yu ◽  
...  
Keyword(s):  
Slow Cooling ◽  
Spectra Analysis ◽  
X Ray ◽  
Cell Parameters ◽  
Growth Defects ◽  
Cooling Method ◽  
Good Crystalline Quality ◽  
Growth Habits ◽  
Top Seeded Solution Growth

High-quality CePO4single crystals (monazite) were grown by the flux TSSG (top-seeded-solution growth) slow-cooling method. The X-ray powder diffraction pattern shows good crystalline quality of the crystals and the various peaks were assigned. The unit-cell parameters were calculated using theDICVOL90andTERORcomputer programs. The concentrations of all elements in the crystals were measured by electron probe microanalysis. Growth habits were deduced by the Bravais–Friedel Donnay–Harker (BFDH) method and macro-defects in the crystals are discussed. An infrared spectrum of the crystal was recorded in the frequency range of 300 to 1600 cm−1and all vibration frequency peaks were assigned.

Characterization of Defect Structures in 3C-SiC Single Crystals Using Synchrotron White Beam X-ray Topography

1996 ◽  
Vol 423 ◽  
Author(s):  
W. Huang ◽  
M. Dudley ◽  
C. Fazi
Keyword(s):  
Single Crystals ◽  
Stacking Faults ◽  
Interference Microscopy ◽  
Defect Structures ◽  
Growth Sector ◽  
X Ray ◽  
Partial Dislocations ◽  
White Beam ◽  
Transmission And Reflection

AbstractDefect structures in (111) 3C-SiC single crystals, grown using the Baikov technique, have been studied using Synchrotron White Beam X-ray Topography (SWBXT). The major types of defects include complex growth sector boundary structures, double positioning twins, stacking faults on { 111 } planes, inclusions and dislocations (including growth dislocations and partial dislocations bounding stacking faults). Detailed stacking fault and double positioning twin configurations are determined using a combination of Nomarski interference microscopy, SEM and white beam x-ray topography in both transmission and reflection geometries. Possible defect generation phenomena are discussed.

High Quality Hydrothermal ZnO Crystals

1998 ◽  
Vol 537 ◽  
Author(s):  
M. Suscavage ◽  
M. Harris ◽  
D. Bliss ◽  
P. Yip ◽  
S.-Q. Wang ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Liquid Helium ◽  
Room Temperature ◽  
Surface Preparation ◽  
Critical Factor ◽  
High Quality ◽  
Rocking Curve ◽  
X Ray ◽  
Oxide Crystals

AbstractZinc Oxide crystals have historically been grown in hydrothermal autoclaves with a basic mineralizer; however, doubts have been raised about the quality of such crystals because they have often exhibited large x-ray rocking curve widths and low photoluminescence (PL) yield with large linewidths. Several ZnO crystals were grown hydrothermally and sliced parallel to the c-plane. This resulted in opposite surfaces (the C+ and C-) exhibiting pronounced chemical and mechanical differences. Different surface treatments were investigated and compared by PL both at room temperature and liquid helium temperatures, and by double axis X-ray rocking curve measurements. The high quality of hydrothermally-grown ZnO is substantiated by the narrow rocking curve widths and sharp PL peaks obtained. A critical factor in obtaining these results was found to be surface preparation.

Growth and characterization of ternary BiScO3–Pb(Cd1/3Nb2/3)O3–PbTiO3 ferroelectric single crystals with high Curie temperature

CrystEngComm ◽  
2020 ◽  
Vol 22 (27) ◽  
pp. 4544-4551
Author(s):  
Zeng Luo ◽  
Jian Zhuang ◽  
Zenghui Liu ◽  
Nan Zhang ◽  
Wei Ren ◽  
...  
Keyword(s):  
Curie Temperature ◽  
Single Crystals ◽  
Solution Growth ◽  
High Curie Temperature ◽  
High Quality ◽  
Domain Structures ◽  
Growth Method ◽  
Top Seeded Solution Growth

BiScO3–Pb(Cd1/3Nb2/3)O3–PbTiO3 single crystals with high quality have been successfully grown by the top-seeded solution growth method and the single ferroelastic domain structures and ferroelectric behaviors have also been reviewed.

Effect of Melt-Back Process on the Quality of Grown Crystal in SiC Solution Growth

2019 ◽  
Vol 963 ◽  
pp. 75-79 ◽  
Author(s):  
Kotaro Kawaguchi ◽  
Kazuaki Seki ◽  
Kazuhiko Kusunoki
Keyword(s):  
Dislocation Density ◽  
Grown Crystal ◽  
Early Stage ◽  
Seed Crystal ◽  
Solution Growth ◽  
Crystal Quality ◽  
Top Seeded Solution Growth ◽  
Koh Etching

We investigated the effect of a melt-back process on the quality of the grown crystal in 4H-SiC solution growth. In our experiments, the crystal was grown by top-seeded solution growth (TSSG) method with and without melt-back, following which the quality of the obtained crystals was compared. When solution growth was carried out without melt-back, solvent inclusions and a different polytype were observed. When molten KOH etching was conducted, the dislocation density in the crystals at the early stage of growth became much higher than that in a seed crystal. Solvent inclusions, a different polytype, and an increase in dislocations were suppressed when solution growth was performed with melt-back. It was confirmed that melt-back is necessary to prevent the deterioration of crystal quality at the early stage of solution growth.

Characterization and Growth Mechanism of B12As2 Epitaxial Layers Grown on (1-100) 15R-SiC

2008 ◽  
Vol 1069 ◽  
Author(s):  
Hui Chen ◽  
Guan Wang ◽  
Michael Dudley ◽  
Zhou Xu ◽  
James. H. Edgar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Growth Mechanism ◽  
Heteroepitaxial Growth ◽  
High Quality ◽  
X Ray ◽  
Transmission Electron ◽  
Substrate Choice

ABSTRACTA systematic study is presented of the heteroepitaxial growth of B12As2 on m-plane 15R-SiC. In contrast to previous studies of B12As2 on other substrates, including (100) Si, (110) Si, (111) Si and (0001) 6H-SiC, single crystalline and untwinned B12As2 was achieved on m-plane 15R-SiC. Observations of IBA on m-plane (1100)15R-SiC by synchrotron white beam x-ray topography (SWBXT) and high resolution transmission electron microscopy (HRTEM) confirm the good quality of the films on the 15R-SiC substrates. The growth mechanism of IBA on m-plane 15R-SiC is discussed. This work demonstrates that m-plane 15R-SiC is potentially a good substrate choice to grow high quality B12As2 epilayers.

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