• Journal of the Korean Ceramic Society
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• v.23 no.4
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• pp.23-26
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• 1986

The synthetic conditions of $ ZrSiO_4-Cd(S_xS_{1-x})$ stains from CdS, Se, $SiO_2$ , 4ZrO_2$ and Lif were investigated and the colors were examined. Colors of the stains prepared were yellow orange red pink ruby and violet in relation to both the content of CdS-Se in $ZrSiO_4$ and firing temperature. Colors of these series stains were thermally stabilized probably by the structural stability of zirconium silicate. Furthermore by the result of X-ray diffraction analysis it is assumed that color of the zircon cadmium sulphoselenide $ ZrSiO_4-Cd(S_xS_{1-x})$ stain is developed by neither the coloring ions in $ZrSiO_4$ lattice nor the solid solution of $ZrSiO_4$ and $Cd(S_xS_{1-x})$ but by the small crystals of $Cd(S_xS_{1-x})$ being occluded by the zirconium silicate during sintering process.

• Analytical Science and Technology
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• v.20 no.5
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• pp.413-418
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• 2007

Poly(vinylpyrrolidone) stabilized cadmium sulfide (CdS) nanoparticles were loaded onto the surface of silica ($SiO_2$) nanoparticles by using ${\gamma}$-irradiation. TEM micrograph reveals the presence of ~20nm sized CdS nanoparticles on the surface of $SiO_2$ nanoparticles. XRD patterns confirm the crystalline. PL spectra of the simple PVP-stabilized CdS nanoparticle and $SiO_2$@CdS composite confirm the differences in the emission characteristics between them. Two prominent emission peaks were noted around 550 nm and 600 nm for PVP-stabilized CdS nanoparticles). The emission peaks noted for the PVP-stabilized CdS nanoparticles were found to be blue shifted for $SiO_2$@CdS composites. Besides, an additional emission peak around 450 nm was noticed for the $SiO_2$@CdS composite. The presence of CdS nanoparticles influence the emission characteristics and induce quantum confinement effect.

• Journal of the Korean Ceramic Society
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• v.30 no.11
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• pp.897-904
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• 1993

CdS doped SiO2 glass coating films which are good candidates for the nonlinear optical materials were prepared by the Sol-Gel method. TEOS, C2H5OH, H2O and HCl were used as starting materials to obtain SiO2 matrix solutions. Then Cd(NO3)2.2H2O and CS(NH2)2 were dissolved into the SiO2 matrix solutions. Coating was performed several times in order to increase the thickness of coated film by the dip-coating method. Then heat treatments were carried out to control the size of CdS microcrystals doped in SiO2 glass matrix with respect to temperatures and times. CdS-doped SiO2 transparent coating films were successfully obtained. CdS crystals were changed from cubic to hexagonal type about $600^{\circ}C$.

• Journal of the Korean Ceramic Society
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• v.33 no.12
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• pp.1353-1364
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• 1996

Recently semiconductor doped glasses have attracted attention as nonlinear optical materials because of their large third order nonlinear optical properties. The transparent and homogeneous CdS-doped SiO2 glass thin films were obtained by the dip=coating process of the sol-gel method. Thin films were consisted of glasses containing CdS microcrystallites which were formed by dissolved Cd2+ and S2- ions in a SiO2 matrix solutions. A subsequent thermal treatment of this samples led the formation of colloidal agglomerates and finally of microcrystallites. The size of CdS microcrystallites was about 4 to 15 nm after thermal treatments at various heating conditions. From the optical absorption spectra of the CdS-doped SiO2 glass films it was found that the absorption edge was blue-shifted compared with that of the bulk CdS crystal(~2, 4 eV) and that the amount of energy shift was inversely proportional to the crystal size. And the band gap energy increased with the decrease in crystallite size indicating that the quantum size effects occured.

• Korean Journal of Materials Research
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• v.9 no.8
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• pp.782-786
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• 1999

CdS thin films prepared by vaccum evaperation have been studied the characteristcs of room temperature of scanning electron microscoe(SEM), X-ray diffraction(XRD), energy dispersive X-ray(EDX), and photoluminescence(PL)spectra. The cubic to hexagonal structure phase transitin has been determined to be $350^{\circ}C~450^{\circ}C$. The results of compensated donor levels of $O_2$and Si impurites at S-vacancy were identified CdO and $Cd_2SiO_4$defects. The edge emission peaks measured by PL of room temperature was donor level accoding the theses $O_2$and Si impurites were due to 2.43eV($350^{\circ}C$) and 2.42eV(55$0^{\circ}C$) peak energies respectively. The structure transition annealing temperature was measured $370^{\circ}C$ similar to Ariza-Calderons result, $374^{\circ}C$ by CBD films.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.4
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• pp.502-506
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• 2012

In order to find the structural characteristics of the thin films of group II-VI semiconductor compounds compared with those of powder materials, films were made of 4 powders of ZnS, CdS, CdSe, and CdTe(Aldrich), each with 99.99 % purity. For the ZnS/CdS multi-layers, the ZnS layer was coated over the CdS layer on an $AlO_x$ membrane, which served as a protective layer within a vacuum at the average speed of 1 ${\AA}$/sec. After studying the structures of the group II-VI semiconductor thin films by using X-ray spectroscopy, we found that the ZnS, ZnS/CdS, CdS, and CdSe films were hexagonal and exhibited some degree of preferred orientation. Also, the particles of the thin films of II-VI semiconductor compounds proved to be more homogeneous in size compared to those of the powder materials. These results were further verified through scanning electron microscopy(SEM), EDX analysis, and powder and thin film X-ray diffraction.

• Journal of the Korean Ceramic Society
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• v.23 no.2
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• pp.50-54
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• 1986

Effects of additionof $NH_4Cl$, NaBr and LiF on the formation of Zircon and the synthesis of CdS-Se red stain were investigated by means of XRD, DTA and the color standard and color nomenclature. The red stain of CdS-Se system shows a little difference dependent on firing temperature on firing conditon. Consequently it forms a good soid-solution with red color under the ratio of CdS and Se 3.5 -4.1 at 58$0^{\circ}C$. But it changes to dark red as increasing Se. LiF is the most effective in mineralizer to preparae zircon with the equilbrant molar $SiO_2$ and ZrO Zircon makes a good preparation in 0.33 mole LiF from 90$0^{\circ}C$.

• Journal of the Korean Ceramic Society
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• v.24 no.2
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• pp.155-160
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• 1987

The investigation includes the application of $ZrSiO_4-Cd(SxSe_{1-x})$stain to ceramic body. The currently developed stain was compared to the commercially available stain in applying to ceremic glaze. Two stains (currently developed and commecially available) were mixed with frits and applied to ceramic tiles. The tiles were fired at 850 to 120$0^{\circ}C$ and tested by colorimeter in X.Y.Z. axis of the wavelength ranging from 580nm to 650nm. Applicability 18 stains to ceramic body was investigated by ISCC-NBS of Munsell color nomenclature. $ZrSiO_4-Cd(SxSe_{1-x})$stain is as good as V and Pr series stain in mixing composition of frits 9 to 1. It maintains red color at 100$0^{\circ}C$ in the mixture of frits, and shows as the strong acid resistance stain.

• Clean Technology
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• v.26 no.4
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• pp.263-269
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• 2020

Zeolite was synthesized hydrothermally using the water-treatment sludge, and the effects of various synthesis parameters like reaction temperature, reaction time, and Na2O/SiO2 molar ratio on the crystallization of zeolite were investigated. Crystal structure, physical property, and thermal stability of zeolite crystals were characterized by X-ray powder diffraction, FTIR spectroscopy, BET nitrogen adsorption, and TGA measurements. The removal efficiencies of nitrogen in ammonia, heavy metal ions, and TOC were calculated to evaluate zeolite's adsorption capacity. The primary chemical composition of water-treatment sludge was 28.79% Al2O3 and 27.06% SiO2. The zeolites were synthesized by merely employing the water-treatment sludge as silica and alumina sources without additional chemicals. Zeolite crystals synthesized through the water-treatment sludge were confirmed as an A-type zeolite structure. Zeolite A had the highest crystallinity obtained from a gel with the molar composition 2.1Na2O-Al2O3-1.6SiO2-65H2O after 5 h at a temperature of 90 ℃. The specific surface area of zeolite obtained was 55 ㎡ g-1, which was higher than commercial zeolite A. The removal efficiency of nitrogen in ammonia was 68% after 3 h of reaction time, while the removal efficiencies of Pb2+ and Cd2+ ions were 99.1% and 99.3%, respectively. These results indicate active ion exchange between Pb2+ or Cd2+ ion and Na+ ion in the zeolite framework. The adsorption experiments on the different zeolite addition conditions were performed for 3 h with 300 ppm humic acid. Based on the results, TOC's highest efficiency was 83% when 5 g of zeolite was added.

• Korean Journal of Materials Research
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• v.18 no.7
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• pp.379-383
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• 2008

We report on the light-emitting diode (LED) characteristics of core-shell CdSe/ZnS nanocrystal quantum dots (QDs) embedded in $TiO_2$thin films on a Si substrate. A simple p-n junction could be formed when nanocrystal QDs on a p-type Si substrate were embedded in ${\sim}5\;nm$ thick $TiO_2$ thin film, which is inherently an n-type semiconductor. The $TiO_2$ thin film was deposited over QDs at $200^{\circ}C$ using plasma-enhanced metallorganic chemical vapor deposition. The LED structure of $TiO_2$/QDs/Si showed typical p-n diode currentvoltage and electroluminescence characteristics. The colloidal core-shell CdSe/ZnS QDs were synthesized via pyrolysis in the range of $220-280^{\circ}C$. Pyrolysis conditions were optimized through systematic studies as functions of synthesis temperature, reaction time, and surfactant amount.