• Solar Energy
• /
• v.11 no.3
• /
• pp.74-83
• /
• 1991

In this study, the (p)ZnTe/(n)Si solar cell and (n)CdS-(p)ZnTe/(n)Si poly-junction thin film are fabricated by vaccum deposition method at the substrate temperature of $200{\pm}1^{\circ}C$ and then their electrical properties are investigated and compared each other. The test results from the (p)ZnTe/(n)Si solar cell the (n)CdS-(p)ZnTe/(n)Si poly-junction thin fiim under the irradiation of solar energy $100[mW/cm^2]$ are as follows; Short circuit current$[mA/cm^2]$ (p)ZnTe/(n)Si:28 (n)CdS-(p)ZnTe/(n)Si:6.5 Open circuit voltage[mV] (p)ZnTe/(n)Si:450 (n)CdS-(p)ZnTe/(n)Si:250 Fill factor (p)ZnTe/(n)Si:0.65 (n)CdS-(p)ZnTe/(n)Si:0.27 Efficiency[%] (p)ZnTe/(n)Si:8.19 (n)CdS-(p)ZnTe/(n)Si:2.3 The thin film characteristics can be improved by annealing. But the (p)ZnTe/(n)Si solar cell are deteriorated at temperatures above $470^{\circ}C$ for annealing time longer than 15[min] and the (n)CdS-(p)ZnTe/(n)Si thin film are deteriorated at temperature about $580^{\circ}C$ for longer than 15[min]. It is found that the sheet resistance decreases with the increase of annealing temperature.

• Transactions on Electrical and Electronic Materials
• /
• v.1 no.3
• /
• pp.18-22
• /
• 2000

In this work, we reported the sulfur compositional variation of ZnS$\_$x/Se$\_$1-x/ epitaxial layers with growth temperature and BEP ration of ZnX/Se/)P$\_$ZnS//P$\_$Se/) grown on GaAs substrates by molecular beam epitaxy. The sulfur composition of ZnSSe epitaxial layers was varied sensitively on the growth temperature and show different linear relationship with growth temperature and BEP ration of ZnS/Se(P$\_$ZnS//P$\_$Se/), which revealed -0.107 %$\^{C}$ at (P$\_$ZnS//P$\_$Se/)=0.30 and -0.052 %$\^{C}$ at (P$\_$ZnS//P$\_$Se/)=0.158 rspectively. A reference data for the accurate control of the sulfur composition and the growth of high quality ZnSSe/GaAs epitaxial layers was provided.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.31 no.7
• /
• pp.443-449
• /
• 2018

We investigated the temperature-dependent photoluminescence spectroscopy of colloidal InZnP/ZnSe/ZnS (core/shell/shell) quantum dots with varying ZnSe and ZnS shell thickness in the 278~363 K temperature range. Temperature-dependent photoluminescence of the InZnP-based quantum dot samples reveal red-shifting of the photoluminescence peaks, thermal quenching of photoluminescence, and broadening of bandwidth with increasing temperature. The degree of band-gap shifting and line broadening as a function of temperature is affected little by shell composition and thickness. However, the thermal quenching of the photoluminescence is strongly dependent on the shell components. The irreversible photoluminescence quenching behavior is dominant for thin-shell-deposited InZnP quantum dots, whereas thick-shelled InZnP quantum dots exhibit superior thermal stability of the photoluminescence intensity.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.34 no.6
• /
• pp.454-460
• /
• 2021

In this work, we synthesized alloy-core InZnP quantum dots, which are more efficient than single-core InP quantum dots, using a solution process method. The effect of synthesis conditions of alloy core on optical properties was investigated. We also investigated the conditions that make up the gradient shell to minimize defects caused by lattice mismatch between the InZnP core and ZnS is 7.7%. The stable synthesis temperature of the InZnP alloy core was 200℃. Quantum dots consisting of three layered ZnSe gradient shell and single layered ZnS exhibited the best optical property. The properties of quantum dots synthesized in 100 ml and in 2,000 ml flasks were almost equal.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.531-531
• /
• 2012

So many groups have been researching the green quantum dots such as InP, InP/ZnS for overcoming the semiconductor nanoparticles composed with heavy metals like as Cd and Pb so on. In spite of much effort to keep up CdSe quantum dots, it does not reach the good properties compared with CdSe/ZnS quantum dots. This quantum dot has improved its properties through the generation of core/shell CdSe/ZnS structure or core/multi-shell structures like as CdSe/CdS/ZnS and CdSe/CdS/ CdZnS/ZnS. In this research, we try to synthesize the InP multi-shell structure by the successiveion layer absorption reaction (SILAR) in the one pot. The synthesized multi-shell structure has improved quantum yield and photo-stability. To generate white light, highly luminescent InP multi-shell quantum dots were mixed with yellow phosphor and integrated on the blue LED chip. This InP multi-shell improved red region of the LEDs and generated high CRI.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.451-451
• /
• 2012

Instead of a highly toxic CdSe and ZnScore-shell,InP/ZnSecore-shell quantum dots [1,2] were investigated as an active material for quantum dot light emitting diode (QD-LED). In this paper, aquantum dot light-emitting diode (QDLED), consisting of a InP/ZnS core-shell type materials, with the device structure of glass/indium-tin-oxide (ITO)/PEDOT:PSS/Poly-TPD/InP-ZnS core-shell quantum dot/Cesium carbonate(CsCO3)/Al was fabricated through a simple spin coating technique. The resulting InP/ZnS core-shell QDs, emitting near blue green wavelength, were more efficient than the above CdSe QDs, and their luminescent properties were comparable to those of CdSe QDs.Thebrightness ofInP/ZnS QDLED was maximumof 179cd/m2.

• Korean Chemical Engineering Research
• /
• v.46 no.1
• /
• pp.170-174
• /
• 2008

ZnS-polymer gel films were prepared with incorporating mesoporous ZnS synthesized by surfactant-assisted templating process and poly (vinylidene fluoride)-hexafluoropropylene copolymer (P(VDF-HFP)) in order to observe the variation of ionic conductivities according to the various weight ratios between ZnS and P(VDF-HFP). Ionic conductivities for each gel electrolyte were measured with increasing temperature. As a result, ionic conductivities increased with increasing the amount of ZnS and temperature. In particular, the films with 20 and 25 wt% ZnS were found that they possessed the high ionic conductivity of approximately $10^{-4}Scm^{-1}$ at room temperature. However, above 20 wt% of ZnS, the enhancement of ionic conductivity was not observed. For the characterization of ZnS and the gel electrolyte, XRD (x-ray diffractometer), DSC (differential scanning calorimetry), TGA (thermogravimetric analysis), FT-IR (fourier transform-infrared spectrometer), SEM (scanning electron microscopy) and TEM (transmission electron microscopy) were employed. Ionic conductivities were measured by a.c. impedance method.

• Journal of Powder Materials
• /
• v.24 no.1
• /
• pp.11-16
• /
• 2017

In this study, simple chemical synthesis of green emitting Cd-free InP/ZnS QDs is accomplished by reacting In, P, Zn, and S precursors by one-pot process. The particle size and the optical properties were tailored, by controlling various experimental conditions, including [In]/[MA] (MA: myristic acid) mole ratio, reaction temperature and reaction time. The results of ultraviolet-visible spectroscopy (UV-vis), and of photoluminescence (PL), reveal that the exciton emission of InP was improved by surface coating, with a layer of ZnS. We report the correlation between each experimental condition and the luminescent properties of InP/ZnS core/shell QDs. Transmission electron microscopy (TEM), and X-ray powder diffraction (XRD) techniques were used to characterize the as-synthesized QDs. In contrast to core nanoparticles, InP/ZnS core/shell treated with surface coating shows a clear ultraviolet peak. Besides this work, we need to study what clearly determines the shell kinetic growth mechanism of InP/ZnS core shell QDs.

• Journal of Information Display
• /
• v.13 no.2
• /
• pp.91-95
• /
• 2012

Indium phosphide (InP) quantum dots (QDs) are considered alternatives to Cd-containing QDs for application in light-emitting devices. The multishell coating with ZnSe/ZnS was shown to improve the photoluminescence quantum yield (QY) of InP QDs more strongly than the conventional ZnS shell coating. Structural proof for this system was provided by X-ray diffraction and transmission electron microscopy. QY values in the range of 50-70% along with peak widths of 45-50 nm can be routinely achieved, making the optical performance of InP/ZnSe/ZnS QDs comparable to that of Cd-based QDs. The fabrication of a working electroluminescent light-emitting device employing the reported material demonstrated the feasibility of the desired application.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.27 no.3
• /
• pp.151-155
• /
• 2014

We have developed quantum dot light emitting diodes (QD-LEDs) using a InP/ZnSe/ZnS multi-shell QD emission layer. The hybrid structure of organic hole transport layer/QD/organic electron transport layer was used for fabricating QD-LEDs. Poly(4-butylphenyl-diphenyl-amine) (poly-TPD) and tris[2,4,6-trimethyl-3-(pyridin-3-yl)phenyl]borane (3TPYMB) molecules were used as hole-transporting and electron-transporting layers, respectively. The emission, current efficiency, and driving characteristics of QD-LEDs with 50, 65 nm thick 3TPYMB layers were investigated. The QD-LED with a 50 nm thick 3TPYMB layer exhibited a maximum current efficiency of 1.3 cd/A.