• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1379-1381
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• 1998

Powder electroluminescent device (PELD) structured conventionally dielectric and phosphor layer, between electrode and their layer fabricated by screen printing splaying or spin coating method. To promote performance of PELDs, we approached the experiments for different structure and thickness variation of PELD. Thickness variation($30{\mu}m{\sim}130{\mu}m$) was taken. To investigate electrical and optical properties of PELDs, EL spectrum, transferred charge density using Sawyer-Tower's circuit brightness was measured. Variation of structure in PELDs was as follows: WK-1 (ITO/BaTiO3/ZnS:Cu/Silver paste), WK-2 (ITO/BaTiO3/ZnS:Cu/BaTiO3/ZnS:Silver paste), WK-3 (ITO/BaTiO3/ZnS:Cu/BaTiO3/Silver paste), WK-4(ITO/BaTiO3+ZnS:Cu/Silver paste) As a result, structure of the highest brightness appeared WK-4 possessed 60 ${\mu}m$ thickness. The brightness was 2719 cd/$m^2$ at 100V, 400Hz.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.5
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• pp.102-107
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• 1996

Use of a rapid thermal annealing (RTA) technique is shown to improve the properties of metal-ferroelectric BaMgF$_{4}$-silicon structures. The fluoride film was deposited in an ultra-high vacuum system at asubstrate temperature of 300$^{\circ}C$. A post-deposition annelaing was conducted for 10 seconds at 600.deg. C in a vacuum of 0.1 Torr, using a home-made RTA apparatus. The results showed that the resistivity of the ferroelectric BaMgF$_{4}$ film from a typical value of 1-2${\times}10^{11}{\Omega}{\cdot}cm$ before the annealing to about 5${\times}10^{13}{\Omega}{\cdot}cm$ and reduce the interface state density of the BaMgF$_{4}$/Si interface to about 8${\times}10^{10}cm^{2}{\cdot}$eV. Ferroelectric hysteresis measurements using a sawyer-tower circuit yielded remanent polarization and coercive field values of about 0.5$\mu$C/cm$^{2}$ and 80 kV/cm, respectively. the typical remanent polarization of the BaMgF$_{4}$ films ont he (100) and (111) oreientated silicon wafers were 0.5 - 0.6 $\mu$C/cm$^{2}$ and that of th efilms on the (110) wafers was 1.2$^{\circ}C$/cm$^{2}$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.2
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• pp.106-110
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• 1998

The $LiNbO_3$ thin films were prepared directly on Si(100) substrates by conventional RF magnetron spurttering system for nonvolatile memory applications. RTA(Rapid Thermal Annealing) treatment was performed for as-deposited films in an oxygen atmosphere at 600 $^{\circ}C$ for 60 s. The rapid thermal annealed films were changed to poly-crystalline ferroelectric nature from amorphous of as-deposition. The resistivity of the ferroelectric $LiNbO_3$ film was increased from a typical value of $1{\sim}2{\times}10^8{\Omega}{\cdot}cm$ before the annealing to about $1{\times}10^{13}{\Omega}{\cdot}cm$ at 500 kV/cm and reduced the interface state density of the $LiNbO_3/Si$ (100) interface to about $1{\times}10^{11}/cm^2{\cdot}eV$. Ferroelectric hysteresis measurements using a Sawyer-Tower circuit yielded remanent polarization ($P_r$) and coercive field ($E_c$) values of about 1.2 ${\mu}C/cm^2$ and 120 kV/cm, respectively.

• Journal of the Korean Vacuum Society
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• v.17 no.2
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• pp.122-129
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• 2008

Ferroelectric properties of the PMT-PT were also studied from the temperature dependence of hysteresis loops using a method slightly modified from Sawyer-Tower's. Dielectric, pyroelectric and piezoelectric properties of the ceramics in the system PMT-PT were investigated. The resulted densities of the PMT-PT ceramics system were greater than 97 % of the theoretical value. As observed SEM micrograph of the fracture surfaces of the PMT-PT ceramics system, the average grain sizes were increased about 3-5 ${\mu}m$ to 6-8 ${\mu}m$ with increasing sintering temperature. The specimens with PT<0.30 for PMT-PT solid solution system exhibited the dielectric and pyroelectric properties of a typical relaxor ferroelectrics. The composition with the maximum dielectric constant exhibits relatively superior pyroelectric and piezoelectric properties.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.21-24
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• 1997

Ferroeletric LiNbO$_3$ thin films hale been prepared directly on Si(100) substrates by conventional RF magnetron spurttering system for nonvolatile memory applications. As-deposited films were performed RTA(Rapid Thermal Annealing) treatment in an oxygen atmosphere at 600 $^{\circ}C$ for 60 s. The rapid thermal annealed films were changed to poly-crystalline ferroelectric nature from amorphous of as-deposition. The resistivity of the ferroelectric LiNbO$_3$ film was increased from a typical vague of 1~2$\times$10$^{8}$ $\Omega$.cm before the annealing to about 1$\times$10$^{13}$ $\Omega$.cm at 500 kV/cm and reduce the interface state density of the LiNbO$_3$/Si(100) interface to about 1$\times$10$^{11}$ cm$^2$ . eV. Ferroelectric hysteresis measurements using a Sawyer-Tower circuit yielded remanent polarization (Pr) and coercive field (Ec) values of about 1.2 $\mu$C/cm$^2$ and 120 kV/cm, respectively.

• Journal of the Semiconductor & Display Technology
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• v.16 no.2
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• pp.44-48
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• 2017

We explain optical and electrical properties of top and bottom-emission structured alternating-current powder electroluminescent devices (ACPELDs) with Ga-doped ZnO(GZO) transparent electrode. The top-emission ACPELDs were layered as the metal electrode/dielectric layer/emission layer/top transparent electrode and the bottom-emission ACPELDs were structured as the bottom transparent electrode/emission layer/dielectric layer/metal electrode. The yellow-emitting ZnS:Mn, Cu phosphor and the barium titanate dielectric layers were layered through the screen printing method. The GZO transparent electrode was deposited by the sputtering, its sheet resistivity is $275{\Omega}/{\Box}$. The transparency at the yellow EL peak was 98 % for GZO. Regardless of EL structures, EL spectra of ACPELDs were exponentially increased with increasing voltages and they were linearly increased with increasing frequencies. It suggests that the EL mechanism was attributed to the impact ionization by charges injected from the interface between emitting phosphor layer and the transparent electrode. The top-emission structure obtained higher EL intensity than the bottom-structure. In addition, charge densities for sinusoidal applied voltages were measured through Sawyer-Tower method.

• Korean Journal of Materials Research
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• v.2 no.1
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• pp.43-51
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• 1992

Thin films of )$Pb(Zr, \;TiO_3$ are fabricated by MOCVD using ultrasonic spraying. The films having perovskite structure are made at low deposition temperature, $300-450^{\circ}C$. The phase and composition of the films vary with the composition of the starting solution and the deposition temperature. Dielectric constant of the films is 187 at 1MHz. Ferroelectric hysterysis loop measurements indicate a remanant polarization of $5.5{\mu}C/cm^2$, and coercive field of 65kV/cm. Resistivity of thin films is about $10^{11}{\Omega}cm$ and the breakdown electric field abort 35kV/cm.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.7
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• pp.77-84
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• 1995

We studied the effects of the Zr/Ti ration and the bottom electrode (Pt or ITO) on the electrical properties of PZT thin films prepared by sol-gel method. Their permittivities and tagent losses with the variation of frequencies were measured by the LCR meter and their maximum polarizations, remanent polarizations, and coercive fields were obtained from the hysteresis loops measured by the Sawyer-Tower circuit. For the PZT thin film of the Zr/Ti ration of 53/47, permittivity at 10kHz, coercive field, maximum and remanent polarizations ere measured as 952, 20.7kV/cm, 10.43${\mu}C/cm^{2}$ and 4.3${\mu}C/cm^{2}$, respectively. For the film of the Zr/Ti ration of 25/75, coercive field, maximum and remanent polarizations were measured as 33.12kV/cm, 5.59${\mu}C/cm^{2}$ and 1.5${\mu}C/cm^{2}$, respectively. For the film of the Zr/Ti ratio of 75/25, they were measured as 23.8kV/cm, 7.45${\mu}C/cm^{2}$, and 3.5${\mu}C/cm^{2}$, repectively. Our investigation into the effects of the lower electrode on the electrical properties of PZT films showed the following results. The permittivities of the PZT films deposited on the ITO electrode decreased more quickly than those of the PZT films on the Pt electrode. The tangent losses of the former films increased more quickly than those of the latter. These may be due to the degradation of the quality of the interface between the electrode and the film, which results from the diffusion of Pb. It is also noticeable that permittivities and tangent losses of the PZT films deposited on the ITO electrode varied differently with the Zr/Ti ratio. This may indicate that the quality of the interface between the electrode and the film changes with the Zr/Ti ration of the PZT film.

• Electrical & Electronic Materials
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• v.10 no.2
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• pp.134-140
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• 1997

PbTiO$_{3}$-PbZrO$_{3}$-Pb(Ni$_{1}$3/Nb $_{2}$3/O$_{3}$)(PZT-PNN) thin films were prepared from corresponding metal organics partially stabilized with diethanolamine by the sol-gel spin coating method. Each mol rates of PT:PZ:PNN solutions were #1(50:40:10), #2(50:30:20), #3(45:35:20) and #4(40:40:20), respectively. The spin-coated PZT-PNN films were sintered at the temperature from 500.deg. C to 600.deg. C for crystallization. The P-E hysteresis curve was drawn by Sawyer-Tower circuit with PZT-PNN film. The coercive field and the remanent polarization of #4(40:40:20 mol%) PZT-PNN film were 28.8 kV/cm and 18.3 .mu.C/cm$^{2}$, respectively. Their dielectric constants were shown between 128 and 1120, and became maximum value in MPB(40:40:20 mol%). The leakage currents of PZT-PNN films were about 9.4x 10$^{-8}$ A/cm$^{2}$, and the breakdown voltages were about 0.14 and 1.1 MV/cm. The Curie point of #3(45:35:20 mol%, sintered at 600.deg. C) film was 330.deg. C.