Optical Properties of Cuprous Oxide Nanocrystals

1996 ◽  
Vol 452 ◽  
Author(s):  
P. J. Rodney ◽  
M. I. Freedhoff ◽  
A. P. Marchetti ◽  
G. L. McLendon ◽  
P. M. Fauchet
Keyword(s):  
Optical Properties ◽  
Standard Deviation ◽  
Low Temperature ◽  
Polyvinyl Alcohol ◽  
Cuprous Oxide ◽  
Blue Shift ◽  
Bulk Crystals ◽  
Exciton Luminescence ◽  
Forbidden Transition ◽  
Size Restriction

AbstractOptical properties of size restricted Cu2O obtained through aqueous and non aqueous preparations are compared with those of commercially available bulk crystals. One method of synthesis involved using polyvinyl alcohol as a restraining agent in an aqueous preparation to produce nanocrystals having diameters with a mean of 11 nm and a standard deviation of 6 nm. Low-temperature spectroscopie studies indicate size restriction effects are manifest by a decrease in exciton luminescence and a 3.0 to 9.0 meV blue shift in 0,0 transition. No noticeable changes in the dynamics were observed for the nanocrystals, indicating no alteration or relaxation of the selection rules for the direct forbidden transition.

Optical properties of ZnTe nanorods synthesized via a facile low-temperature solvothermal route

2010 ◽  
Vol 171 (1-3) ◽  
pp. 11-15 ◽  
Author(s):  
Buyong Wan ◽  
Chenguo Hu ◽  
Bin Feng ◽  
Jing Xu ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Low Temperature ◽  
Solvothermal Route

Optical properties of quantum wells grown upon gas source molecular‐beam epitaxy low‐temperature buffers

1991 ◽  
Vol 69 (11) ◽  
pp. 7942-7944 ◽  
Author(s):  
K. T. Shiralagi ◽  
R. A. Puechner ◽  
K. Y. Choi ◽  
R. Droopad ◽  
G. N. Maracas
Keyword(s):  
Optical Properties ◽  
Molecular Beam Epitaxy ◽  
Low Temperature ◽  
Quantum Wells ◽  
Molecular Beam ◽  
Gas Source

Cuprous oxide thin films prepared by thermal oxidation of copper layer. Morphological and optical properties

2015 ◽  
Vol 159 ◽  
pp. 325-332 ◽  
Author(s):  
Artak Karapetyan ◽  
Anna Reymers ◽  
Suzanne Giorgio ◽  
Carole Fauquet ◽  
Laszlo Sajti ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Thermal Oxidation ◽  
Cuprous Oxide ◽  
Copper Layer ◽  
Oxide Thin Films

Study the Effect of Heat Treatment and Pressure on some the Optical Properties of the Pure PVA Nano Polymer

2021 ◽  
Vol 900 ◽  
pp. 16-25
Author(s):  
Tabarak Mohammed Awad ◽  
May A.S. Mohammed
Keyword(s):  
Heat Treatment ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Optical Properties ◽  
Absorption Coefficient ◽  
Polyvinyl Alcohol ◽  
Complex Dielectric Constant ◽  
Different Temperatures ◽  
German Origin ◽  
Increasing Temperature

In this study, some optical properties were studied of the pure vinyl polyvinyl alcohol (PVA) nanopolymer (German origin). Under the influence of different temperatures and pressures of PVA. Where 25 samples were prepared for the purpose of conducting the research. Which studied the study of these samples was done by recording the absorbance and transmittance spectra of the wavelengths (200-900) nm. From them, absorbance, transmittance, reflectivity, absorption coefficient, refractive index, extinction coefficient, complex dielectric constant were calculated. At different temperatures (25,40, 80, 120, 160)°C. And with different pressures within the range (7.5,8,8.5,9,9.5) MPa. The results are that the permeability of the polymer (PVA) at different temperatures for each pressure decreases with increasing temperature, and that all other calculated optical properties increase with increasing temperature.

Ultra-precision grinding of 4H-SiC wafer by PAV/PF composite sol-gel diamond wheel

2021 ◽  
Vol 13 (9) ◽  
pp. 168781402110449
Author(s):  
Kaiping Feng ◽  
Tianchen Zhao ◽  
Binghai Lyu ◽  
Zhaozhong Zhou
Keyword(s):  
Surface Roughness ◽  
Low Temperature ◽  
Polyvinyl Alcohol ◽  
Feed Rate ◽  
Hot Pressing ◽  
Phenolic Resin ◽  
Sol Gel ◽  
Diamond Wheel ◽  
Sic Wafer ◽  
Better Than

To eliminate the deep scratches on the 4H-SiC wafer surface in the grinding process, a PVA/PF composite sol-gel diamond wheel was proposed. Diamond and fillers are sheared and dispersed in the polyvinyl alcohol-phenolic resin composite sol glue, repeatedly frozen at a low temperature of −20°C to gel, then 180°C sintering to obtain the diamond wheel. Study shows that the molecular chain of polyvinyl alcohol-phenolic resin is physically cross-linked to form gel under low-temperature conditions. Tested by mechanical property testing machines, microhardness tester, and SEM. The results show that micromorphology is more uniform, the strength of the sol-gel diamond wheel is higher, the hardness uniformity is better than that of the hot pressing diamond wheel. Grinding experiments of 4H-SiC wafer were carried out with the prepared sol-gel diamond wheel. The influence of grinding speed, feed rate, and grinding depth on the surface roughness was investigated. The results showed that by using the sol-gel diamond wheel, the surface quality of 4H-SiC wafer with an average surface roughness Ra 6.42 nm was obtained under grinding wheel speed 7000 r/min, grinding feed rate 6 µm/min, and grinding depth 15 µm, the surface quality was better than that of using hot pressing diamond wheel.

scholarly journals Optimized Soft Lithography Method for Polymer Cholesteric Liquid Crystal Flakes Fabrication

Micromachines ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 441 ◽  
Author(s):  
Guanqing Zhou ◽  
Sunqian Liu ◽  
Wei Liu ◽  
Dong Yuan ◽  
Guofu Zhou
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Polyvinyl Alcohol ◽  
Soft Lithography ◽  
Cholesteric Liquid Crystal ◽  
Release Time ◽  
Pdms Mold ◽  
Speed Up ◽  
Liquid Crystal Flakes

Polymer cholesteric liquid crystal (PCLC) flakes are gaining increasing interest for a wide variety of applications because of their unique optical properties and capabilities. Soft lithography is the most effective way to fabricate regularly shaped PCLC flakes. However, it is not easy to peel the flakes from the mold without breaking them. In order to peel the PCLC flakes from the patterned polydimethylsiloxane (PDMS) mold in a convenient way, in this paper, a method of coating a layer of polyvinyl alcohol (PVA) on a PDMS mold was proposed. The influence of the thickness of the PVA layer on the shape of the PCLC flakes and the release time from the PDMS mold were investigated. The results show that the presence of the PVA layer can speed up the release of the PCLC flakes and help maintain the shape effectively. Notably, the utilization of a PVA layer makes the PDMS mold recyclable. The influence of PCLC flake shape was also studied. This work will promote the development of switchable PCLC flake-based technologies.

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