• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.5
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• pp.283-295
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• 2021

For the last decades, a research hotspot for the halide perovskites (HPs) is now showing great progress in terms of improving efficiency for numerous photovoltaic devices (PVDs). However, it still faces challenges in the case of long-term stability in the air atmosphere. Defect-free high-quality HP single crystals show their promising properties for the remarkable development of highly efficient and stable PVDs. Here, we summarize the growth processing routes for the stable HP single crystals as well as briefly discuss the pros and cons of those well-established synthesis routes. Furthermore, we briefly include the comparison note between the HP single crystals and polycrystalline perovskite films regarding their device applications. Based on the future progress, the review concludes subjective perspectives and current challenges for the development of HPs high-quality PVDs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.208-211
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• 2000

Ba(Mg$_{1}$3/$Nb_{2/3}$)O$_3$ powders were synthesised from mechanochemically treated mixtures of Ba(OH)$_2$. 8$H_2O$, MgO and Nb$_2$O$_{5}$. Perovskite BMN powder of nanosized particles was successfully synthesized by using mechanochemical methods. Density and dielectric constant of samples with mechanochemical methods showed higher values than those of conventional processing.ng.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.84-87
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• 2000

The microwave dielectric properties of complex perovskite-structured $Ba(Mg_{1/3}Ta_{2/3})O_3$ ceramics were investigated with calcining condition. The BMT ceramics were prepared by conventional mixed oxide method. Calcining conditions were $1200^{\circ}C$ for 10hr., $1300^{\circ}C$ for 2hr., and 5hr., respectively. And the specimens were sintered at $1650{\mu}m$. The structural and microwave properties of BMT ceramics were investigated by XRD, SEM and network analyzer. In the case of BMT ceramics calcined at $1300^{\circ}C$ for 5 hr., dielectric constant, quality factor and temperature coefficient of resonant frequency were 20.26, 31,144(at 1GHz), 6.11[ppm/$^{\circ}C$], respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.10
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• pp.873-877
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• 2007

In order to apply a complex multilayer chip LC filter, this study has estimated the interfacial reaction and coupling properties of dielectric materials $Pb(Fe_{1/2}Nb_{1/2})O_3$ and Ni-Zn-Cu ferrite materials through low-temperature co-sintering (LTCS). PFN powders were fabricated using double calcinated at $700^{\circ}C$ and then $850^{\circ}C$. While the perovskite phase rate was found to be 91 %, after heat treatment at $900^{\circ}C$ for 6h, the perovskite phase rate and density exhibited a value of 100 % and 7.46$g/cm^3$, respectively. The PFN/Ni-Zn-Cu ferrite, PFN/CUO (or $Pb_2Fe_2O_5$) and ferrite/CuO (or $Pb_2Fe_2O_5$) were mechanically coupled through interfacial reactions after the specimen was co-sintered at $900^{\circ}C$ for 6 h. No intermediate layer exists for the mutual coupling reaction. This result indicates the possibility of low-temperature co-sintering without any interfacial reaction layer for a multilayer chip LC filter.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.165-166
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• 2008

$(Ba_{0.6},Sr_{0.3},Ca_{0.1})TiO_3$ powders, which were prepared by sol-gel method using a solution of Ba-acetate, Sr-acetate and Ca-acetate and Ti iso-propoxide, were mixed with organic vehicle and the BSCT thick films were fabricated by the screen-printing techniques on high purity alumina substrates. The structural and dielectirc properties were investigated for various $Pr_2O_3$ and $Y_2O_3$doping contents. As a result of thermal analysis of $(Ba_{0.6},Sr_{0.3},Ca_{0.1})TiO_3$ powders, the exothermic peak was observed at around $670^{\circ}C$ due to the formation of the polycrystalline perovskite phase. All BSCT thick films, sintered at $1420^{\circ}C$ for 2h, showed the typical XRD patterns of perovskite polycrystalline structure. The average grain size of the specimens decreased with amount of $Pr_2O_3$ and $Y_2O_3$ contents.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.167-167
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• 2008

The barium strontium calcium titanate powders were prepared by sol-gel method. Ferroelectric $(Ba_{0.54}Sr_{0.36}Ca_{0.1})TiO_3$(BSCT) thick films were fabricated by the screen-printing method on alumina substrate. And we investigated the structural and dielectric properties of BSCT thick films with the variation of sintering temperature. As a result of thermal analysis, BSCT polycrystalline perovskite phase was formed at around $660^{\circ}C$. The results of X-ray diffraction analysis were showed a cubic perovskite structure without presence of the second phase in all BSCT thick films. The average grain size and the thickness of the specimen sintered at $1450^{\circ}C$ were about 1.6 mm and 45 mm, respectively. The relative dielectric constant increased and the dielectric loss decreased with increasing the sintering temperature, the values of the BSCT thick films sintered at $1450^{\circ}C$ were 5641 and 0.4% at 1kHz, respectively.

• Transactions on Electrical and Electronic Materials
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• v.16 no.1
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• pp.1-4
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• 2015

(111)-oriented and random oriented $Pb_{0.8}Ba_{0.2}ZrO_3$ (PBZ) perovskite relaxor ferroelectric thin films were fabricated on Pt(111)/$TiO_x$/$SiO_2$/Si substrate by sol-gel method. Nano-scaled antiferroelectric and ferroelectric two-phase coexisted in both (111)-oriented and random oriented PBZ thin film. High dielectric tunability (${\eta}=75%$, E = 560 kV/cm) and figure-of-merit (FOM ~ 236) at room temperature was obtained in (111)-oriented thin film. Meanwhile, giant electrocaloric effect (ECE) (${\Delta}T=45.3K$ and ${\Delta}S=46.9JK^{-1}kg^{-1}$ at $598kVcm^{-1}$) at room temperature (290 K), rather than at its Curie temperature (408 K), was observed in random oriented $Pb_{0.8}Ba_{0.2}ZrO_3$ (PBZ) thin film, which makes it a promising material for the application to cooling systems near room temperature. The giant ECE as well as high dielectric tunability are attributed to the coexistence of AFE and FE phases and field-induced nano-scaled AFE to FE phase transition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.245-248
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• 2003

Randomly oriented ferroelectric cerium-substituted $Bi_4Ti_3O_{12}$ thin films have been prepared by using metal-organic decomposition method. The layered perovskite structure was investigated using annealing for 1 h in the temperature range from $550\;{\sim}\;750\;^{\circ}C$. The structure and morphology of the films were characterized using X-ray diffraction and scanning electron microscopy The $Bi_{3.4}Ce_{0.6}Ti_3O_{12}$ (BCeT) thin films showed a perovskite phase and dense microstructure. The grain size of the BCeT films increasedwith increasing annealing temperature. The hysteresis loops of the films were well defined at temperatures above $600\;^{\circ}C$. The 200-nm-thick BCeT thin films annealed at $650\;^{\circ}C$ showed a large remanent polarization (2Pr) of 59.3 ${\mu}C/cm^2$ at an applied voltage of 10 V. The BCeT thin films showed good fatigue endurance up to $5\;{\times}\;10^9$ bipolar cycling at 5 V and 100 kHz.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.337-340
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• 1999

Since the first reports of CMR(colossal magnetoresistance) effects in some single crystal R-P Phase Ln$_{1-x}$ Sr$_{2-x}$Mn$_{2}$O$_{7}$ 1996. many researches have been carried out to find optimum compositions and processing conditions in this system. In this study, layered perovskite R-P Phase Ln$_{1-x}$ Sr$_{2-x}$Mn$_{2}$O$_{7}$ (x=0.4, Ln=-La, Eu, Gd, Nd, Pr, Sm) phases were synthesized by solid state reaction and their structures were refined by Rietveld method. Electrical and magnetic properties were measured drown to 20K and compare with those of R-P Phase Ln$_{1-x}$ Sr$_{2-x}$Mn$_{2}$O$_{7}$ Phases.es.es.es.es.es.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.217-220
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• 2000

The SrBi$_2$Ta$_2$O$\_$9/(SBT) thin films are deposited on Pt-coated electrode(Pt/TiO$_2$/SiO$_2$/Si) using RF sputtering method. The SBT thin films deposited on substrate at 400-500[$^{\circ}C$]. SBT thin film deposited on Pt-coated electrodes have the cubic perovskite structure and polycrystalline state. With increasing annealing temperature from 600[$^{\circ}C$] to 850[$^{\circ}C$], flourite phase was crystallized to 650[。 and Bi-layered perovskite phase was crystallize ed above 700[$^{\circ}C$]. The maximum remnant polarization and the coercive electric field is 11.73[${\mu}$C/$\textrm{cm}^2$], 85[kV/cm] respectively at annealing temperature of 750[$^{\circ}C$]. The fatigue characteristics of SBT thin films deposited on Pt/TiO$_2$/SiO$_2$/Si substrate did not change up to 10$\^$10/ switching cycles.