• 한국전기전자재료학회논문지
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• 제14권11호
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• pp.892-897
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• 2001

Variations of dielectric and piezoelectric properties and associated phase transformation of <001> -oriented rhombohedral 0.92Pb (Zn$\sub$1/3/Nb$\sub$2/3/)O$_3$-0.08PbTiO$_3$ single crystals were investigated. The longitudinal strain level was found to abruptly increase at 15 kV/cm, corresponding to that where an induced phase appears within a multidomain matrix. Drastic decreases in the dielectric constant, transverse coupling, and transverse piezoelectric coefficient associated with the E-field induced phase were the result of increased crystal anisotropy in PZN-PT crystals. By contrast, the thickness coupling increased from 53 % at 0 kV/cm to 64 % at 45 kV/cm, also associated with this phase transition under the E-field. The measured dielectric and piezflelectric properties found for the induced phase state were nearly identical to those of <001> poled tetragonal (1-x)PZN-xPT (x>0.1) crystals. Based on these results, it is evident that the symmetry of induced phase is tetragonal.

• 한국전기전자재료학회논문지
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• 제13권9호
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• pp.745-750
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• 2000

The (S $r_{0.85}$C $a_{0.15}$) Ti $O_3$(SCT) thin films are deposited on Pt-coated electrode (Pt/TiN/ $SiO_2$/Si) using RF sputtering method at various deposition temperature. The crystallinity of SCT thin films were increased with increase of deposition temperature in the temperature range of 200~500[$^{\circ}C$]. Also, the composition of SCT thin films were closed to stoichiometry (1.080~1.111 in A/B ratio). V-I characteristics of SCT thin films show the increasing leakage current with the increases of deposition temperature. The conduction mechanism of the SCT thin films observed in the temperature range of 25~100[$^{\circ}C$] can be divided into four regions with different mechanism by the increasing current. The region I below 0.8[MV/cm]shows the ohmic conduction. The region II between 0.9~2[MV/cm] is in proportion to J∝ $E^{1.5}$ , the region III between 2~4[MV/cm] can be explained by the Child’s law, and the region IV above 4[MV/cm]is dominated by the tunneling effect.ect.

• 한국전기전자재료학회논문지
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• 제17권3호
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• pp.323-328
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• 2004

Down-conversion of Eu$^{3+}$ doped LiGdF$_4$ (LGF) for increasing the cell efficiency on dye-sensitized Ti $O_2$ solar cells has been studied. The dye sensitized solar cell (DSC) consisting of mesoporous Ti $O_2$ electrode deposited on transparent substrate, an electrolyte containing I$^{[-10]}$ /I$_3$$^{[-10]}$ redox couple, and Pt counter electrode is a promising alternative to the inorganic solar cell. The structure of DSC is basically a sandwich type, viz., FTO glass/Ru-red dye-absorbed Ti $O_2$/iodine electrolyte/sputtered Pt/FTO glass. The cell without down converter had open circuit potential of approximately 0.66 Volt, the short circuit photocurrent density of 1.632 mA/$\textrm{cm}^2$, and fill factor of about 50 ％ at the excitation wavelength of 550 nm. In addition, 5.6 mW/$\textrm{cm}^2$ incident light intensity beam was used as a light source. From this result, the calculated monochromatic efficiency at the wavelength of 550 nm of this cell was about 9.62 ％. The incident photon to current conversion efficiency (IPCE) of N3 used as a dye in this work is about 80 ％ at around 590 nm and 610 nm, which is the emission spectrum of Eu$^{3+}$ doped LGF, results in efficiency increasing of DSC.C.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.5-6
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• 2006

Using the $(Ba_{0.5}Sr_{0.5}){TiO_3}$(BST) powders prepared by the Sol-Gel method, the EST thick films were fabricated on the ${Al_2}{O_3}$ substrates coated with Pt by the screen printing method. Compared with pure EST thick films, the structural and dielectric properties of the EST thick films doped with 1${\sim}$10 wt % MgO were investigated. It was observed that the Mg substitution into EST causes a shift in the cubic-tetragonal EST phase transition peak to a lower temperature. The microstructure of the EST substituted with Mg was homogeneous and dense. Mg substitution into EST had a significant effect on the grain size reduction. Dielectric constant was decreased with increasing the MgO content and temperature. In the case of EST thick films doped with 1 wt% MgO, the relative permittivity and dielectric loss were 158] and 1.4 % at 1 MHz.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 일렉트렛트 및 응용기술
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• pp.58-62
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• 2002

Pb($Zr_{0.52}Ti_{0.48}$)$O_3$ (PZT) thin films deposited on the Pt/Ti and Ru/$RuO_2$ bottom electrode by rf magnetron sputtering methode. Ru/$RuO_2$ bottom electrode deposited on the p-type wafer as Ru thickness by in-situ process. Our results show that all PZT films indicated perovskite polycrystalline structure with perferred orientation (110) and no pyrochlore phase is observed. A well-fabricated $RuO_2$/PZT/Ru(100nm)/$RUO_2$ capacitor showed a leakage current density in the order of $2.13{\times}10^{-7}A/cm^2$ as 100 kV/cm, a remanent polarization of 7.20 ${\mu}C/cm^2$, and a coercive field of 58.37 kV/cm. The results show that the new Ru/$RuO_2$ bottom electrodes are expected to reduce the degradation ferroelectric fatigue and excellent ferroelectric properties.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2016년도 정기학술대회 발표논문집
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• pp.125-125
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• 2016

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2000년도 추계총회,초청강연,특별강연,연구발표회
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• pp.180.2-180
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• 2000

• 한국전자현미경학회:학술대회논문집
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• 한국현미경학회 1994년도 제25회 학술대회 연제 초록
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• pp.23-23
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• 1994

• 한국전기전자재료학회논문지
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• 제28권9호
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• pp.598-601
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• 2015

The $Sr_{0.7}Bi_{2.3}Nb_2O_9(SBN)$ thin films are deposited on Pt electrode($Pt/Ti/SiO_2/Si$) using RF sputtering method at various deposition temperature. The deposition temperature of optimum was $300^{\circ}C$. SBN thin films were annealed at $500{\sim}700^{\circ}C$ using furnace and RTA, respectively. The surface roughness showed about 2.42 nm in annealing temperature($600^{\circ}C$) of furnace. The capacitance density of SBN thin films were increased with the increase of annealing temperature. The maximum capacitance density of $0.7{\mu}F/cm^2$ was obtained by annealing temperature($700^{\circ}C$). The frequency dependence of dielectric loss showed about 0.03 in frequency ranges of 1~1,000 kHz.

• Transactions on Electrical and Electronic Materials
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• 제11권5호
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• pp.212-215
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• 2010

$BiFeO_3/Pb(Zr_{0.95}Ti_{0.05})O_3$ (BFO/PZT) heterolayered thin films were fabricated by the spin coating method on a Pt/Ti/$SiO_2$/Si substrate using metal alkoxide solutions. The coating and heating procedure was repeated 6 times to form the heterolayered films. The thickness of the BFO/PZT films after one cycle of drying/sintering is about 30-40 nm. All BFO/PZT films show a void free uniform grain structure without the presence of rosette structures. It can be assumed that the crystal growth of the upper BFO layers can be influenced by the lower PZT layers. As the number of coatings increased, the dielectric constant increased, so that the value for the 6-layer film was 1360 at 1 KHz.