scholarly journals Absorption spectra of single-crystal and optical ceramics of fluorite in terahertz and infrared ranges

2019 ◽  
Vol 487 (1) ◽  
pp. 20-23
Author(s):  
G. A. Komandin ◽  
V. S. Nozdrin ◽  
P. P. Fedorov ◽  
V. V. Osiko
Keyword(s):  
Single Crystal ◽  
Absorption Spectra ◽  
Room Temperature ◽  
Reflectance Spectra ◽  
Optical Characteristics ◽  
Transmission Spectra ◽  
Optical Ceramics ◽  
High Absorption

The transmission spectra of a single crystal, artificial and natural fluorite ceramics were recorded in the areas of material transparency in THz and the average IR range at room temperature. In the region of high absorption, the reflectance spectra were measured. Differences in the optical characteristics of a single crystal and optical ceramics are insignificant.

Characteristic Investigations of Stoichiometric LiNbO3 Single Crystal Fiber Co-Doped with Tb and Mn

2004 ◽  
Vol 449-452 ◽  
pp. 985-988
Author(s):  
S.M. Lee ◽  
J.W. Shur ◽  
T.I. Shin ◽  
W.S. Yang ◽  
G.Y. Kim ◽  
...  
Keyword(s):  
Absorption Band ◽  
Single Crystal ◽  
Optical Microscopy ◽  
Single Crystals ◽  
Absorption Spectra ◽  
Room Temperature ◽  
Crystal Fiber ◽  
Ft Ir ◽  
Homogeneous Distributions ◽  
Co Doped

[MnO2(1.0mol%) : Tb4O7(0.5mo%)] doped stoichiometric LiNbO3 (Mn:Tb:SLN) single crystals of 0.5~1.0 mm in diameter and 30~35 mm in length were grown by micro pulling down(µ-PD) method. We investigated the photoluminescence (PL) properties of Mn:Tb:SLN single crystal. The OH- absorption band of the single crystals observed infrared the absorption spectra by using an FT-IR spectrophotometer at room temperature. Homogeneous distributions of Mn and Tb concentration were confirmed by the EPMA and observed defects by optical microscopy.

scholarly journals Optical Properties of Porous Silicon p-Si (100)

2019 ◽  
Vol 20 (3) ◽  
pp. 264-268
Author(s):  
P.O. Gentsar ◽  
M.V. Vuichyk ◽  
M.V. Isaev ◽  
P.O. Lischuk
Keyword(s):  
Optical Properties ◽  
Porous Silicon ◽  
Single Crystal ◽  
Pore Size ◽  
Band Gap ◽  
Spectral Range ◽  
Reflectance Spectra ◽  
Transmission Spectra

In this paper the reflectance spectra and transmission spectra of p-Si (100) porous silicon (PS) and silicon wires in the spectral range of 200 ÷ 1800 nm were investigated. Pore size of PS was 5 μm (lpor Si layer) and 50 μm (lpor Si layer) with porosity of 45 %, 55 % and 65 %. The length of silicon wires varies from 5.5 μm, to 50 μm with a porosity of 60 %. The decrease in the band gap of p-Si (100) porous silicon and silicon wires which grown on both sides of p-Si (100) as compared to the single crystal p-Si (100) is explained by the quantum-sized effect that occurs in the investigated objects.

Hetero-Epitaxial Defects and Optical Characteristics of SiCGe Layers Grown on 6H-SiC Substrate

2010 ◽  
Vol 663-665 ◽  
pp. 445-448
Author(s):  
Tao Lin ◽  
Nan Lin ◽  
Lian Bi Li ◽  
Chen Yang ◽  
Hong Bin Pu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Optical Transmission ◽  
Optical Characteristics ◽  
Layer By Layer ◽  
Transmission Spectra ◽  
Photoluminescence Spectra ◽  
Peak Wavelength ◽  
Room Temperature Photoluminescence ◽  
Layer Mode ◽  
Optical Transmission Spectra

By means of SEM, TEM, UV-VIS optical transmission spectra and photoluminescence spectra tests, hetero-epitaxial defects and optical characteristics of SiCGe layers grown on 6H-SiC substrate were studied. SEM and TEM images have shown that the SiCGe were grown in layer-by-layer mode with APD and DPB defects which were caused by the thermal and lattice mismatches between SiCGe and SiC. Transmission spectra results have shown the calculated band gap of the SiCGe layer was 2.31eV. Room temperature photoluminescence spectra have shown that the peak wavelength and the FWHM of SiCGe layer were closely related to its Ge contents and the hetero-epitaxial defects.

Normal-State Infrared Anisotropy of Polycrystalline La1.85Sr0.15CuO4-y

1987 ◽  
Vol 99 ◽  
Author(s):  
G. L. Doll ◽  
J. Steinbeck ◽  
M. S. Dresselhaus ◽  
G. Dresselhaus ◽  
A. J. Strauss ◽  
...  
Keyword(s):  
Optical Properties ◽  
Single Crystal ◽  
Electronic Properties ◽  
Normal State ◽  
Superconducting State ◽  
Optical Anisotropy ◽  
Room Temperature ◽  
Reflectance Spectra ◽  
Frequency Range ◽  
Ir Studies

ABSTRACTBy examining the reflectance spectra of polycrystalline La1.85Sr0.15CuO4-y and La2NiO4-y in relation to the results of ir studies on single-crystal La2NiO4-y, we have determined the normal-state (room temperature) optical anisotropy of La1.85Sr0.15CuO4-y in the frequency range 40 cm-1 to 4800 cm-1. Vibrational and electronic properties corresponding to this anisotropy are examined, and a method is presented for extracting the optical properties of the superconducting state of La1.85Sr0.15CuO4-y.

Mechanical Properties and Dislocation Structure of Single Crystal Cdte Deformed in Compression at 300°C

1976 ◽  
Vol 34 ◽  
pp. 592-593
Author(s):  
Ernest L. Hall ◽  
J. B. Vander Sande
Keyword(s):  
Mechanical Properties ◽  
Single Crystal ◽  
Dislocation Structure ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Optical Devices ◽  
Semiconductor Compound ◽  
Wide Range ◽  
Sample Orientation

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

scholarly journals Old Donors for New Molecular Conductors: Combining TMTSF and BEDT-TTF with Anionic (TaF6)1−x/(PF6)x Alloys

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 386
Author(s):  
Magali Allain ◽  
Cécile Mézière ◽  
Pascale Auban-Senzier ◽  
Narcis Avarvari
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
Density Wave ◽  
Spin Density Wave ◽  
Orthorhombic Phase ◽  
Molecular Conductors ◽  
Bechgaard Salts ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Resistivity Measurements

Tetramethyl-tetraselenafulvalene (TMTSF) and bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF) are flagship precursors in the field of molecular (super)conductors. The electrocrystallization of these donors in the presence of (n-Bu4N)TaF6 or mixtures of (n-Bu4N)TaF6 and (n-Bu4N)PF6 provided Bechgaard salts formulated as (TMTSF)2(TaF6)0.84(PF6)0.16, (TMTSF)2(TaF6)0.56(PF6)0.44, (TMTSF)2(TaF6)0.44(PF6)0.56 and (TMTSF)2(TaF6)0.12(PF6)0.88, together with the monoclinic and orthorhombic phases δm-(BEDT-TTF)2(TaF6)0.94(PF6)0.06 and δo-(BEDT-TTF)2(TaF6)0.43(PF6)0.57, respectively. The use of BEDT-TTF and a mixture of (n-Bu4N)TaF6/TaF5 afforded the 1:1 phase (BEDT-TTF)2(TaF6)2·CH2Cl2. The precise Ta/P ratio in the alloys has been determined by an accurate single crystal X-ray data analysis and was corroborated with solution 19F NMR measurements. In the previously unknown crystalline phase (BEDT-TTF)2(TaF6)2·CH2Cl2 the donors organize in dimers interacting laterally yet no organic-inorganic segregation is observed. Single crystal resistivity measurements on the TMTSF based materials show typical behavior of the Bechgaard phases with room temperature conductivity σ ≈ 100 S/cm and localization below 12 K indicative of a spin density wave transition. The orthorhombic phase δo-(BEDT-TTF)2(TaF6)0.43(PF6)0.57 is semiconducting with the room temperature conductivity estimated to be σ ≈ 0.16–0.5 S/cm while the compound (BEDT-TTF)2(TaF6)2·CH2Cl2 is also a semiconductor, yet with a much lower room temperature conductivity value of 0.001 to 0.0025 S/cm, in agreement with the +1 oxidation state and strong dimerization of the donors.

scholarly journals Composite Material of PDMS with Interchangeable Transmittance: Study of Optical, Mechanical Properties and Wettability

2021 ◽  
Vol 5 (4) ◽  
pp. 110
Author(s):  
Flaminio Sales ◽  
Andrews Souza ◽  
Ronaldo Ariati ◽  
Verônica Noronha ◽  
Elder Giovanetti ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Room Temperature ◽  
Casting Process ◽  
Optical Characteristics ◽  
Smart Devices ◽  
Superhydrophobic Coating ◽  
Gravity Casting ◽  
High Flexibility ◽  
Physical And Chemical

Polydimethylsiloxane (PDMS) is a polymer that has attracted the attention of researchers due to its unique properties such as transparency, biocompatibility, high flexibility, and physical and chemical stability. In addition, PDMS modification and combination with other materials can expand its range of applications. For instance, the ability to perform superhydrophobic coating allows for the manufacture of lenses. However, many of these processes are complex and expensive. One of the most promising modifications, which consists of the development of an interchangeable coating, capable of changing its optical characteristics according to some stimuli, has been underexplored. Thus, we report an experimental study of the mechanical and optical properties and wettability of pure PDMS and of two PDMS composites with the addition of 1% paraffin or beeswax using a gravity casting process. The composites’ tensile strength and hardness were lower when compared with pure PDMS. However, the contact angle was increased, reaching the highest values when using the paraffin additive. Additionally, these composites have shown interesting results for the spectrophotometry tests, i.e., the material changed its optical characteristics when heated, going from opaque at room temperature to transparent, with transmittance around 75%, at 70 °C. As a result, these materials have great potential for use in smart devices, such as sensors, due to its ability to change its transparency at high temperatures.

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