• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.12 no.5
• /
• pp.223-228
• /
• 2002

We have studied the characteristics of Raman scattering spectroscopy from $_ZnS{1-x}Te_x$ alloys in the whole range of Te composition x. The Raman spectra showed two-mode behaviors for those alloys. The Raman line shape showed the changes of an asymmetry and broadening of that with Te composition x. The asymmetric broadening of the line shape could be explained with a spatial correlation model.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1989.06a
• /
• pp.56-58
• /
• 1989

All-polycrystalline Cd$_1$-xZnxS/CdTe solar cells have been fabricated by coating CdTe slurries with 4.5 wt% of CdCl$_2$on the sintered Cd$_1$-xZnxS films and by sintering CdTe layer at 6$25^{\circ}C$ for lh in nitrogen atmosphere. Solar efficiency of the sintered Cd$_1$-xZnxS/CdTe solar cells increases as the Zn content increases up to x=0.06 and then decreases with further increase in the Zn content. A solar efficiency of 12.5% under a solar intensity of 76mW/$\textrm{cm}^2$ was observed in a Cd 0.94 Zn0.06S/CdTe solar cell. By optimizing the amount of CdCl$_2$in the slurry and sintering conditions, it is possible to produce Cd$_1$-xZnxS/CdTe solar cells with efficiency higher than 12%.

• Journal of the Mineralogical Society of Korea
• /
• v.9 no.2
• /
• pp.93-101
• /
• 1996

Behavior of platinum group elements during crystallization within ore magma is of interest. In this study platinum is selected and its mineralogical and geochemical behavior in the presence of antimony and tellurium is investigated at 600$^{\circ}C$. High purity Pt, Sb, and Te are used as starting material and silica quartz tubings are as container. Rection products have been examined by use of ore microscope, X-ray diffractometer, electron microprobe analyser and micro-indentation hardness tester. stable phases at 600$^{\circ}C$ are platinum (Pt), Pt5Sb, Pt3Sb, PtSb, stumpflite (PtSb), geversite (PtSb), PtTe, Pt3Te4, Pt2Te3, moncheite (PtTe2), tellurantimony (Sb2Te3), and antimony (Sb). Geversite is the mineral showing the most significant extent of solid solution by up to 27 at% between Sb and Te elements. Isothermal section of 600$^{\circ}C$ is established in this study. It is noted that platinum cannot coexists with stumpflite or geversite under equilibrium condition, and stumpflite composition in equilibrium with geversite may be used as geothermometer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.03a
• /
• pp.11-11
• /
• 2010

In order to design for nano structured materials with enhanced thermoelectric properties, the alloys in the pseudo-binary $Bi_2Te_3$-PbTe system were investigated for their micro structure and thermal properties. For this synthesis the liquid alloys were cooled by water quenching method. The micro structure images were taken by using electron probe micro analyzer (EPMA). Dendritic and lamellar structures were clearly observed with the variation in the composition ratio between $Bi_2Te_3$ and PbTe. It was confirmed that a metastable compounds is $PbBi_2Te_4$ in the The $Bi_2Te_3$-PbTe system. The change in the composition increasing $Bi_2Te_3$ ratio causes to change structure from dendritic to lamellar. Seebeck coefficient of alloys 5 which the mixture rate of $Bi_2Te_3$ is 83% was measured as the highest value. In contrast, the others decreased by increasing $Bi_2Te_3$. n-type characteristics was observed at all condition except alloy 6 which $Bi_2Te_3$ ration is 91%. The power factors of all samples were calculated with Seebeck coefficient and resistivity. Also the thermal conductivity was measured by using laser flash analyzer (LFA). In this work, the microstructures and thermal properties have been measured as a function of ratio of $Bi_2Te_3$ in the $Bi_2Te_3$-PbTe system.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.7 no.4
• /
• pp.548-554
• /
• 1997

The single crystal of $Mg_{0.16}Zn_{0.84}$Te:Co(Co:0.01 mole%) was grown by vertical Bridgman method. The crystal structure of $Mg_{0.16}Zn$_{0.84}$Te:Co and optical absorption properties of this compound were studied. The grown single crystal has a cubic structure and a lattice constant a=6.1422 $\AA$ were determined by X-ray diffraction. As a result of the optical absorption spectra of $Mg_{0.16}Zn_{0.84}$Te:Co, the intracenter transitions due to $Co^{2+}$ ions were detected for $A-band:^4A_2(^4F){\to}^4T_2(^4F),\; B-band:^4A_2(^4F){\to}^4T_1(^4F), C- band:^4A_2(^4F){\to}^4T_1(^4P)$.The charge transfer transition near the absorption edge was observed in the wavelength range of 550 to 770 nm. According to the crystal field theory, the crystal field parameter(Dq) and the Racah parameter(B) were determined.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.197.2-197.2
• /
• 2015

Low-cost, high efficiency solar cells are tremendous interests for the realization of a renewable and clean energy source. ZnTe based solar cells have a possibility of high efficiency with formation of an intermediated energy band structure by impurity doping. In this work, the ZnTe:O/CdS/ZnO structure was fabricated by pulsed laser deposition (PLD) technique. A pulsed (10 Hz) Nd:YAG laser operating at a wavelength of 266 nm was used to produce a plasma plume from an ablated a ZnTe target, whose density of laser energy was 4.5 J/cm2. The base pressure of the chamber was kept at a pressure of approximately $4{\times}10-7Torr$. ZnO thin film with thickness of 100 nm was grown on to ITO/glass, and then CdS and ZnTe:O thin film were grown on ZnO thin film. Thickness of CdS and ZnTe:O were 50 nm and 500 nm, respectively. During deposition of ZnTe:O films, O2 gas was introduced from 1 to 20 mTorr. For fabricating ZnTe:O/CdS/ZnO solar cells, Au metal was deposited on the ITO film and ZnTe:O by thermal evaporation method. From the fabricated ZnTe:O/CdS/ZnO solar cell, current-voltage characteristics was measured by using HP 4156-a semiconductor parameter analyzer. Finally, solar cell performance was measured using an Air Mass 1.5 Global (AM 1.5 G) solar simulator with an irradiation intensity of 100 mW cm-2.

• Journal of the Korean Ceramic Society
• /
• v.29 no.11
• /
• pp.855-862
• /
• 1992

Thermoelectric power, electrical conductivity and Hall effect were measured, as functions of temperature in the range of 100 to 600 K, on polycrystalline Bi4/3Sb2/3Te3 which had been prepared via uniaxial hot-pressing at different temperatures in the range of 373 K to 773 K, aiming at searching a profitable processing route to a polycrystalline thermoelectric material, a promising, viable alternative to a single crystalline one. It was found that, with increasing temperature of pressing under a fixed pressure, the material, normally a p-type prior to being hot-pressed, underwent a transition to n-type. This transition was confirmed to be due to plastic deformation during hot-pressing and interpreted as being attributed to the change of the major ionic defect BiTe' into TeBi˙at temperature high enough for structure elements mobility. Thermoelectric figure-of-merit of the hot-pressed material was discussed in connection with the p-n transition in addition to microstructure.

• Korean journal of food and cookery science
• /
• v.26 no.3
• /
• pp.246-251
• /
• 2010

This study was conducted to investigate the quality characteristics of guavapyun after the addition of different ratios of extract (0.25, 0.5, 0.75, 1.0%), non-extract and vitamin C. The quality if the pyun containing 0.5% of the guava fruit extract (guavapyun) and vitamin C was higher compared with the quality of the control pyun. In the results of the proximatecomposition, the content of water was high in the control pyun relative to the vitamin C pyun and guavapyun and the carbohydrate, ash, crude lipid and protein content was high in guavapyun. The sweetness, pH and color (L, a, b value) were very high in the samples. The texture, hardness, chewiness and gumminess were significantly high in the control pyun and the adhesiveness and cohesiveness were high in guavapyun. However, there were no significant differences in springiness between the control and the added samples. The total phenolic content was higher in guavapyun (23.57 mg GAE/100 g) than the control pyun (18 mg GAE/100 g) and vitamin C pyun(15.05 mg GAE/100 g). The antioxidant activities determined by the DPPH method and ABTS method was higher in guavapyun (41.37 mM TE/g, 15.35 mM TE/g) than the control pyun (4.43 mM TE/g, 2.17mM TE/g) and vitamin C pyun (11.33 mM TE/g, 4.51 mM TE/g). Using the FRAP method, guavapyun(9.06 mM TE/g) was shown to exhibit a stronger ferrous ion chelating activity than the control pyun (4.49mM TE/g) and vitamin C pyun (7.03 mM TE/g). Thus, the studied indigenous guavapyun was high in both antioxidative activity and total phenolic content.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.247.1-247.1
• /
• 2016

Low-cost, high efficiency solar cells are tremendous interests for the realization of a renewable and clean energy source. ZnTe based solar cells have a possibility of high efficiency with formation of an intermediated energy band structure by impurity doping. In this work, ZnO/ZnTe:Cr and ZnO/i-ZnTe structures were fabricated by pulsed laser deposition (PLD) technique. A pulsed (10 Hz) Nd:YAG laser operating at a wavelength of 266 nm was used to produce a plasma plume from an ablated a ZnTe target, whose density of laser energy was 10 J/cm2. The base pressure of the chamber was kept at approximately $4{\times}10-7Torr$. ZnTe:Cr and i-ZnTe thin films with thickness of 210 nm were grown on p-Si substrate, respectively, and then ZnO thin films with thickness of 150 nm were grown on ZnTe:Cr layer under oxygen partial pressure of 3 mTorr. Growth temperature of all the films was set to $250^{\circ}C$. For fabricating ZnO/i-ZnTe and ZnO/ZnTe:Cr solar cells, indium metal and Ti/Au grid patterns were deposited on back and front side of the solar cells by using thermal evaporator, respectively. From the fabricated ZnO/ZnTe:Cr and ZnO/i-ZnTe solar cell, dark currents were measured by using Keithley 2600. Solar cell parameters were obtained under Air Mass 1.5 Global solar simulator with an irradiation intensity of 100 mW/cm2, and then the photoelectric conversion efficiency values of ZnO/ZnTe:Cr and ZnO/i-ZnTe solar cells were measured at 1.5 % and 0.3 %, respectively.

• Journal of Surface Science and Engineering
• /
• v.49 no.1
• /
• pp.40-45
• /
• 2016

Recently, $Bi_2Te_3$-based alloys are the best thermoelectric materials near to room temperature, so it has been researched to achieve increased figure of merit(ZT). Ternary compounds such as Bi-Te-Se and Bi-Sb-Te have higher thermoelectric property than binary compound Bi-Te and Sb-Te, respectively. Compared to DC plating method, pulsed electrodeposition is able to control parameters including average current density, and on/off pulse time etc. Thereby the morphology and properties of the films can be improved. In this study, we electrodeposited n-type ternary Cu-doped $Bi_2(Te-Se)_3$ thin film by modified pulse technique at room temperature. To further enhance thermoelectric properties of $Bi_2(Te-Se)_3$ thin film, we optimized Cu doping concentration in $Bi_2(Te-Se)_3$ thin film and correlated it to electrical and thermoelectric properties. Thus, the crystal, electrical, and thermoelectric properties of electrodeposited $Bi_2(Te-Se)_3$ thin film were characterized the XRD, SEM, EDS, Seebeck measurement, and Hall effect measurement, respectively. As a result, the thermoelectric properties of Cu-doped $Bi_2(Te-Se)_3$ thin films were observed that the Seebeck coefficient is $-101.2{\mu}V/K$ and the power factor is $1412.6{\mu}W/mK^2$ at 10 mg of Cu weight. The power factor of Cu-doped $Bi_2(Te-Se)_3$ thin film is 1.4 times higher than undoped $Bi_2(Te-Se)_3$ thin film.