• Title/Summary/Keyword: $BaTiO_{3}$

Search Result 1,478, Processing Time 0.027 seconds

Solid-state Lighting용 형광체 $BaTiO_3$:$Pr^{3+}$:$Ga^{3+}$의 발광특성에 대한 연구

  • Lee, Dong-Ju;Yu, Yeong-Gi;Gang, Seong-Gu
    • Proceedings of the Optical Society of Korea Conference
    • /
    • 2008.02a
    • /
    • pp.403-405
    • /
    • 2008
  • Solid state lighting 용 적색 형광체로 적용하기 위하여 $BaTiO_3$:$Pr^{3+}$:$Ga^{3+}$를 다음과 같이 합성하였다. 출발 물질로 $BaCO_3$,$Pr(NO_3)_3$ $6H_2O$, $TiO_2$, $Ga_2O_3$을 사용 하였으며, $BaTiO_3$:$Pr^{3+}\;_x$(x=$0.001{\sim}0.2$):$Ga^{3+}\;_y$(y=0.05, 0.1, 0.5 1, 2, 3)를 각각의 조성대로 혼합한 후 $600^{\circ}C$에서 10시간 전처리 하였다. 전처리한 시료를 시편으로 제조하여 $1200^{\circ}C$ 공기중에 4시간 소성하여 최종물질인 $BaTiO_3$:$Pr^{3+}\;_x$:$Ga^{3+}\;_y$을 얻었다. 이 화합물을 X-선 회절 분석 결과 공간군 P4MM을 갖는 페로브스카이트임을 알 수 있었다. 이 화합물을 적색형광체로 적용하기 위해 PL과 PLE측정을 통하여 형광특성을 알아본 결과 618nm에서 x=0.011, y=1.0 일 때 특성이 가장 우수한 것으로 나타났다.

  • PDF

The Etching Mechanism of $(Ba, Sr)TiO_3$Thin Films in $Ar/CF_4$ High Density Plasma ($Ar/CF_4$ 고밀도 플라즈마에서 $(Ba, Sr)TiO_3$ 박막의 식각 메카니즘)

  • Kim, Seung-Beom;Kim, Chang-Il
    • The Transactions of the Korean Institute of Electrical Engineers C
    • /
    • v.49 no.5
    • /
    • pp.265-269
    • /
    • 2000
  • $(Ba, Sr)TiO_3$thin films were etched with a magnetically enhanced inductively coupled plasma (MEICP) at different CF4/Ar gas mixing ratios. Experimental was done by varying the etching parameters such as rf power, dc bias and chamber pressure. The maximum etch rate of the BST films was $1800{AA}/min$ under $CF_4/(CF_4+Ar)$ of 0.1, 600 W/350 V and 5 mTorr. The selectivity of BST to Pt and PR was 0.6, 0.7, respectively. X-ray photoelectron spectroscopy (XPS) results show that surface reaction between Ba, Sr, Ti and C, F radicals occurs during the (Ba, Sr)TiO3 etching. To analyze the composition of surface residue after the etching, films etched with different CF_4/Ar$ gas mixing ratio were investigated using XPS and secondary ion mass spectroscopy (SIMS).

  • PDF

Capacitance Aging Behavior of Acceptor-Doped BaTiO3 under DC Electrical Field (직류 전계에 의한 Acceptor 첨가 BaTiO3의 유전특성 열화 현상)

  • Hahn, Dong-Woo;Han, Young-Ho
    • Journal of the Korean Ceramic Society
    • /
    • v.46 no.2
    • /
    • pp.219-223
    • /
    • 2009
  • Effects of MgO or $R_2O_3$(R:Dy, Ho, Yb) on the capacitance aging behavior of multilayer ceramic capacitors (MLCCs) based on $BaTiO_3$ dielectrics under DC electrical fields has been studied. At a DC field of 1 $V{/\mu}m$, the capacitance of MLCC specimens dropped immediately in a very short period (<10 s, the first stage) and then decreased continuously with time (the second stage). Mn doping significantly increased the aging rate in the second stage. The addition of MgO or $R_2O_3$ notably decreased the second stage aging rate of Mn-doped specimens. Yb doping gives rise to the lowest aging rate in the second stage, which is due to the larger population of defect dipoles associated with oxygen vacancies.

유전체 재료용 Phosphate계 유리-BNT($BaO-Nd_{2}O_{3}-TiO_{2}$)계 세라믹 복합체의 특성

  • 이회관;이용수;황성건;강원호
    • Proceedings of the Korean Society Of Semiconductor Equipment Technology
    • /
    • 2004.05a
    • /
    • pp.234-239
    • /
    • 2004
  • 본 연구에서는 마이크로파용 유전재료로서 널리 사용되고 있는 BNT($BaO-Nd_{2}O_{3}-TiO_{2}$)계 세라믹스를 기본조성으로 하고, 저융점의 phoshpate계 유리 프릿의 첨가를 통해 LTCC(Low Temperature Cofired Ceramic)에 적용 가능한 유전율을 가진 조성을 개발 하고자, $70P_{2}O_{5}-5B_{2}O_{3}-(25-x)BaO-xNa_{2}O$ 유리를 제조 및 특성을 평가하였다. 또한, BNT계 세라믹스에 glass frit을 5 - 15 wt% 범위에서 첨가하고, $800 - 950^{\circ}C$의 온도범위에서 소결하여 제조된 유리-세라믹 복합체의 소결특성 및 유전특성을 조사하였다.

  • PDF

Application of Layered Perovskites Substituted with Co and Ti as Electrodes in SOFCs (Co 및 Ti가 치환된 Layered perovskite의 SOFC 전극에 대한 적용성 연구)

  • Kim, Chan Gyu;Shin, Tae Ho;Nam, Jung Hyun;Kim, Jung Hyun
    • New & Renewable Energy
    • /
    • v.18 no.2
    • /
    • pp.40-49
    • /
    • 2022
  • In this study, the phase and electrochemical properties of Co and Ti substituted layered perovskites SmBaCo2-xTixO5+d (x=0.5, 0.7, 1.0, 1.1, 1.3, and 1.5) were analyzed, and their application as electrodes in solid oxide fuel cells (SOFCs) were evaluated. After calcination at 1300℃ for 6 h, a single phase was observed for two compositions of the SmBaCo2-xTixO5+d oxide system, SmBaCoTiO5+d (x=1.0) and SmBaCo0.9Ti1.1O5+d (x=1.1). However, the phases of SmBaCoTiO5+d (SBCTO) and SmTiO3 coexisted for compositions with x≥1.3 (Ti content). In contrast, for compositions of x≤0.7, the SmBaCo2O5+d phase was observed instead of the SmTiO3 phase. To evaluate the applicability of these materials as SOFC electrodes, the electrical conductivities were measured under various atmospheres (air, N2, and H2). SBCTO exhibited stable semi-conductor electrical conductivity behavior in an air and N2 atmosphere. However, SBCTO showed insulator behavior at temperatures above 600℃ in a H2 atmosphere. Therefore, SBCTO may only be used as cathode materials. Moreover, SBCTO had an area specific resistance (ASR) value of 0.140 Ω·cm2 at 750℃.

Microwave Dielectric Properties of BaO-$(Nd,\;Bi)_2O_3-Tio_2$ Ceramic for Microwave Resonators (고주파 공진기용 BaO-$(Nd,\;Bi)_2O_3-Tio_2$계 세라믹스의 마이크로파 유전특성)

  • Yoon, Jung-Rag;Lee, Heun-Yong
    • Proceedings of the KIEE Conference
    • /
    • 1997.11a
    • /
    • pp.320-323
    • /
    • 1997
  • The microwave dielectric properties of X Ba0-$0.15(Nd_{0.87}Bi_{0.13})_2O_3$-(0.85-X) $TiO_2$ ($X=0.13{\sim}0.17$) and 0.16Ba0-$0.15(Bi_xNd_{1-x})_2O_3-0.69TiO_2$ ($X=0.10{\sim}0.16$) ceramics were investigated. Dielectric constant, quality factor and temperature coefficient of resonant frequency of 0.16Ba0-$0.15(Nd_{0.87}Bi_{0.13})_2O_3-0.69TiO_2$ ceramics sintered at $1320^{\circ}C$ for 2 hours were 89.2, 1920(at 4GHz) and 5.2ppm/$^{\circ}C$, respectively.

  • PDF