Single-Crystal Aluminum Nitride Substrate Preparation from Bulk Crystals

2001 ◽  
Vol 680 ◽  
Author(s):  
J. Carlos Rojo ◽  
Leo J. Schowalter ◽  
Kenneth Morgan ◽  
Doru I. Florescu ◽  
Fred H. Pollak ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Analysis ◽  
Dislocation Density ◽  
Single Crystal ◽  
High Strain ◽  
Bulk Crystals ◽  
Scanning Thermal Microscopy ◽  
Substrate Preparation ◽  
X Ray ◽  
Differential Expansion

ABSTRACTLarge (15mm diameter) single-crystal AlN boules have been prepared using sublimationrecondensation growth. X-ray topography shows that the dislocation density averages less than 103 cm2 in some of the substrates but also that the dislocations are not uniformly distributed. Also, strain due to the differential expansion with the crucible walls seems to cause severe cracking in the periphery of the crystal and high-strain regions. Thermal analysis using the Scanning Thermal Microscopy (SThM) reveals a thermal conductivity of 3.4 ± 0.2 W/K-cm, which is the largest value ever reported for AlN.

Progress in the Preparation of Aluminum Nitride Substrates from Bulk Crystals

2002 ◽  
Vol 722 ◽  
Author(s):  
J.C. Rojo ◽  
L.J. Schowalter ◽  
Glen Slack ◽  
K. Morgan ◽  
J. Barani ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Aluminum Nitride ◽  
Single Crystal ◽  
Central Region ◽  
Electronic Device ◽  
Bulk Crystals ◽  
High Quality ◽  
X Ray ◽  
Uv Led

AbstractLarge (11-mm diameter) single-crystal AlN boules have been prepared using sublimationrecondensation growth. X-ray topography shows that substrates prepared from those boules have a dislocation density of less than 500 cm-2, while the central region of these substrates was nearly dislocation-free. Rocking curves of less than 10 arcsecs have been obtained indicating the high quality of these crystals. The AlN substrates have been used to growth an AlGaN/AlN multiquantum well structure with excellent crystalline quality and with photoluminescence peaked at around 260nm. In addition, a UV LED with emission wavelength at 360nm has been fabricated. This is the first operating opto-electronic device demonstrated on an AlN substrate.

Synthesis, IR spectrum, thermal behaviour and crystal structure of a novel one-dimensional cyano-bridged zinc(II)/nickel(II) complex

2005 ◽  
Vol 220 (1) ◽  
Author(s):  
Ahmet Karadag ◽  
Hümeyra Pasaoglu ◽  
Gökhan Kastas ◽  
Orhan Büyükgüngör
Keyword(s):  
Crystal Structure ◽  
Thermal Analysis ◽  
Coordination Polymer ◽  
Single Crystal ◽  
Ir Spectrum ◽  
Polymeric Chain ◽  
X Ray Diffraction ◽  
Bimetallic Complex ◽  
One Dimensional ◽  
X Ray

AbstractThe cyano-bridged heteronuclear coordination polymer of zinc(II)/nickel(II) has been prepared by N-(2-hydroxyethyl)-ethylendiamine (hydet-en), alternatively named 2-(2-aminoethylamino)-ethanol and characterised by IR and thermal analysis. In the bimetallic complex, the decomposition of hydet-en ligands is seen to be endothermic whereas that of the cyano ligands is found to be exothermic. The crystal structure of the complex has been determined by single-crystal X-ray diffraction. The crystal structure of the zinc(II)-nickel(II) complex consists of a one-dimensional polymeric chain –Zn(hydet-en)

New solvates and a salt of the anti-HIV compound etravirine

2021 ◽  
Vol 77 (11) ◽  
Author(s):  
Marieta Muresan-Pop ◽  
Sergiu Macavei ◽  
Alexandru Turza ◽  
Gheorghe Borodi
Keyword(s):  
Thermal Analysis ◽  
Ir Spectroscopy ◽  
Force Field ◽  
Single Crystal ◽  
Total Energy ◽  
Hirshfeld Surface ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Energies ◽  
Anti Hiv

Four new solvates of the anti-HIV compound etravirine [systematic name: 4-({6-amino-5-bromo-2-[(4-cyanophenyl)amino]pyrimidin-4-yl}oxy)-3,5-dimethylbenzonitrile, C20H15BrN6O] with dimethyl sulfoxide (C2H6OS, two distinct monosolvates), 1,4-dioxane (C4H8O2, the 0.75-solvate) and N,N-dimethylacetamide (C4H9NO, the monosolvate), which exhibit conversion to the same anhydrous etravirine phase upon desolvation, and a stable etravirinium oxalate salt {6-amino-5-bromo-4-(4-cyano-2,6-dimethylphenoxy)-2-[(4-cyanophenyl)amino]pyrimidin-1-ium hemioxalate, C20H16BrN6O+·0.5C2O4 2−} were obtained. The crystal structures were solved by single-crystal X-ray diffraction and analyzed by powder X-ray diffraction, and the intermolecular interactions were explored by Hirshfeld surface analysis. Lattice energies were evaluated using the atom–atom force field Coulomb–London–Pauli (AA CLP) approximation, which distributes the total energy as four separate contributions: Coulombic, polarization, dispersion and repulsion. The formation of the solvates and the oxalate salt was further characterized by thermal analysis and IR spectroscopy.

Lumefantrine Comparative Study: Single Crystal, Powder X-Ray Diffraction, Hirshfeld Surface, and Thermal Analysis

2020 ◽  
Vol 61 (1) ◽  
pp. 151-159
Author(s):  
M. B. de Freitas-Marques ◽  
M. I. Yoshida ◽  
C. Fernandes ◽  
B. L. Rodrigues ◽  
W. N. Mussel
Keyword(s):  
Thermal Analysis ◽  
Comparative Study ◽  
Single Crystal ◽  
Hirshfeld Surface ◽  
X Ray Diffraction ◽  
X Ray

Co-crystal formation between 2-amino-4,6-dimethylpyrimidine and new p-xylylene-bis(thioacetic) acid

CrystEngComm ◽  
2014 ◽  
Vol 16 (44) ◽  
pp. 10262-10272 ◽  
Author(s):  
A. Ostasz ◽  
R. Łyszczek ◽  
L. Mazur ◽  
B. Tarasiuk
Keyword(s):  
Thermal Analysis ◽  
Infrared Spectroscopy ◽  
Single Crystal ◽  
Crystal Formation ◽  
Thioacetic Acid ◽  
X Ray Diffraction ◽  
X Ray ◽  
Analysis Methods

Novelp-xylylene-bis(thioacetic) acid (p-XBTA) and its co-crystals with 2-amino-4,6-dimethylpyrimidine (DMP) have been synthesized and characterized by single-crystal X-ray diffraction, infrared spectroscopy and thermal analysis methods (TG/DSC).

Synthesis and characterization of the pentazolate anion cyclo-N5ˉ in (N5)6(H3O)3(NH4)4Cl

Science ◽  
2017 ◽  
Vol 355 (6323) ◽  
pp. 374-376 ◽  
Author(s):  
Chong Zhang ◽  
Chengguo Sun ◽  
Bingcheng Hu ◽  
Chuanming Yu ◽  
Ming Lu
Keyword(s):  
Thermal Analysis ◽  
Single Crystal ◽  
Diffraction Analysis ◽  
Decomposition Temperature ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Onset Decomposition Temperature ◽  
The Stability

Pentazole (HN5), an unstable molecular ring comprising five nitrogen atoms, has been of great interest to researchers for the better part of a century. We report the synthesis and characterization of the pentazolate anion stabilized in a (N5)6(H3O)3(NH4)4Cl salt. The anion was generated by direct cleavage of the C–N bond in a multisubstituted arylpentazole using m-chloroperbenzoic acid and ferrous bisglycinate. The structure was confirmed by single-crystal x-ray diffraction analysis, which highlighted stabilization of the cyclo-N5ˉ ring by chloride, ammonium, and hydronium. Thermal analysis indicated the stability of the salt below 117°C on the basis of thermogravimetry-measured onset decomposition temperature.

Synthesis, crystal structure and fluorescence spectrum of a cadmium(II) sulfaquinoxaline complex

2013 ◽  
Vol 69 (11) ◽  
pp. 1332-1335 ◽  
Author(s):  
Xiu-Hua Zhao ◽  
Ya-Yun Zhao ◽  
Jie Zhang ◽  
Jian-Guo Pan ◽  
Xing Li
Keyword(s):  
Thermal Analysis ◽  
Single Crystal ◽  
Fluorescence Spectrum ◽  
Chain Structure ◽  
Zigzag Chain ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
X Ray ◽  
Distorted Octahedral Coordination Geometry ◽  
Distorted Octahedral

catena-Poly[[[4-amino-N-(quinoxalin-2-yl)benzenesulfonamidato]aquacadmium(II)]-μ-4-amino-N-(quinoxalin-2-yl)benzenesulfonamidato], [Cd(C14H11N4O2S)2(H2O)], has been synthesized hydrothermally and characterized by single-crystal X-ray diffraction, elemental analysis, fluorescence, IR and thermal analysis. Single-crystal X-ray analysis reveals that the complex is a one-dimensional zigzag chain structure, and the CdIIcation has a distorted octahedral coordination geometry formed by five N atoms from three different sulfaquinoxaline ligands and one O atom from a water molecule. The fluorescence spectrum reveals that the complex emits strong blue fluorescence and thermal analysis shows that the complex has high thermal stability.

Spiro fused β-lactam cyclopropenes

1992 ◽  
Vol 70 (12) ◽  
pp. 2967-2971 ◽  
Author(s):  
Michel Zoghbi ◽  
John Warkentin
Keyword(s):  
Molecular Structure ◽  
Single Crystal ◽  
Strain Energy ◽  
High Strain ◽  
Dimethyl Acetylenedicarboxylate ◽  
X Ray Diffraction ◽  
Cyclopropene Ring ◽  
X Ray ◽  
Lactam Ring ◽  
High Strain Energy

Δ3-1,3,4-Oxadiazolines (1) that share their C2 with C4 of a β-lactam ring in a spiro fusion were prepared. The structures were established through single crystal X-ray diffraction of 1a and by infrared, 1H, and 13C nuclear magnetic resonance spectroscopies. Thermolysis of 1 at 100 °C, in benzene containing dimethyl acetylenedicarboxylate, afforded spiro-fused β-lactam cyclopropene 12 in 33% yield. Similar thermolysis of 1b in the presence of ethyl phenylpropiolate gave spiro-fused β-lactam cyclopropene 13 (32%). The molecular structure of 12, determined by single crystal X-ray diffraction, has the two ester carbonyl carbons out of the plane of the cyclopropene ring by about 0.17 Ǻ, indicating substantial nonbonded steric interactions and suggesting unusually high strain energy. At 154.5 °C, 12 underwent isomerization to 19, presumably through a vinyl carbene intermediate.

Mortars Based on a Ternary Binder from Lime, Metakaolin and Calcium Hemihydrate

2020 ◽  
Vol 868 ◽  
pp. 105-118
Author(s):  
Vladimír Pavlík ◽  
Alena Struhárová
Keyword(s):  
Thermal Conductivity ◽  
Thermal Analysis ◽  
Drying Shrinkage ◽  
Normal Weight ◽  
Expanded Perlite ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
Humid Atmosphere ◽  
X Ray ◽  
Sand Filler

Normal-weight mortars with quartz sand filler and lightweight mortars with expanded perlite filler were prepared from a lime-metakaolin-gypsum binder. Mortar test samples were cured in a humid atmosphere and also in the laboratory ambient conditions. Development of hardening processes was studied by X-ray diffraction, thermal analysis and SEM-EDS observation. Compressive strength, drying shrinkage, bulk density and thermal conductivity of the mortars were determined. The presence of gypsum binder in the mixtures enabled formation of ettringite that caused expansion and reduced drying shrinkage of mortars with 20% content of gypsum binder.

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