• 한국세라믹학회지
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• 제55권5호
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• pp.504-509
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• 2018

The influence of yttrium doping on varistor properties of zinc-vanadium-based ceramics was comprehensively investigated. The average grain size varied slightly between 5.2 and $5.5{\mu}m$ as the yttrium content increased; and similarly, the sintered density varied slightly between 5.47 and $5.51g/cm^3$. The threshold field exhibited a maximum value (5387 V/cm) when the yttrium content was 0.1 mol%. The highest nonlinear exponent (67) was obtained when the yttrium content was 0.05 mol%. The donor concentration increased in the range of $(2.46-5.56){\times}10^{17}cm^{-3}$ as the yttrium content increased, and the maximum barrier height was obtained (1.24 eV) when the yttrium content reached 0.05 mol%.

• Journal of Electrochemical Science and Technology
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• 제12권2호
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• pp.272-278
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• 2021

In this study, high nickel layered LiNi_0.8Co_0.1Mn_0.1O₂ cathode materials for lithium-ion batteries were modified by yttrium doping and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) coating. The effects of yttrium doping and PEDOT:PSS coating on the structural and electrochemical properties of the LiNi_0.8Co_0.1Mn_0.1O₂ cathode material were investigated and compared. The substitution of nickel with an electrochemically inert yttrium was confirmed to be successful in stabilizing the layered structure framework. Moreover, coating the surfaces of the LiNi_0.8Co_0.1Mn_0.1O₂ particles with a conductive polymer, PEDOT:PSS, improved the capacity retention, thermal stability, and impedance of the cathode material by increasing its ionic and electric conductivities.

• 한국전기전자재료학회논문지
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• 제33권6호
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• pp.445-449
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• 2020

Non-volatile memory is approaching its fundamental limits with the Si₃N₄ storage layer, necessitating the use of alternative materials to achieve a higher programming/erasing speed, larger storage window, and better data retention at lower operating voltage. This limitation has restricted the development of the charge-trap memory, but can be addressed by using high-k dielectrics. The paper reviews the doping of nitrogen, titanium, and yttrium on high-k dielectrics as a storage layer by comparing MONOS devices with different storage layers. The results show that nitrogen doping increases the storage window of the Gd₂O₃ storage layer and improves its charge retention. Titanium doping can increase the charge capture rate of HfO₂ storage layer. Yttrium doping increases the storage window of the BaTiO₃ storage layer and improves its fatigue characteristics. Parameters such as the dielectric constant, leakage current, and speed of the memory device can be controlled by maintaining a suitable amount of external impurities in the device.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.350-350
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• 2013

Sol-gel법을 이용하여 p-Si 기판위에 yttrium이 도핑된 ZnO (YZO)를 성장하였다. ZnO의 precursor로는 zinc acetate dihydrate를, yttrium의 source로는 yttrium acetate hydrate를 사용하였으며, 용매와 안정제로는 각각 2-methoxy ethanol과 monoethanolamine (MEA)를 사용하였다. yttrium의 doping 농도에 따른 영향을 알아보기 위하여 1~4 at.%로 제작된 YZO sol을 각각 p-type Si 기판에 성장하였으며, 이 후 furnace를 이용하여 500oC에서 1시간 동안 열처리하였다. 성장된 YZO 박막의 표면과 두께를 SEM을 통하여 확인하였으며, XRD를 통한 구조적인 특성을 분석한 결과 모든 박막에서 뚜렷한 c-축 배양성을 갖는 ZnO (0002)피크를 확인하였다. Hall effect를 통하여 YZO는 모두 n-type 특성을 나타낸다는 것을 확인하였으며, 광학적인 특성은 PL을 통해서 분석하였다. n-YZO/p-Si 이종접합의 전류-전압 특성을 분석한 결과 뚜렷한 정류특성을 나타내었다.

• 한국세라믹학회지
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• 제50권6호
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• pp.451-453
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• 2013

Porous ceramic membranes consisting of $Ce_{1-x}Y_xO_{2-{\delta}}$ were developed for hydrogen permeation tests. Various amounts (x = 0, 0.05, 0.1, 0.2) of yttrium were doped to ceria to study the effect of yttrium doping on ceria membranes on various properties, including hydrogen permeability. $Ce_{1-x}Y_xO_{2-{\delta}}$ powder was synthesized by the sol-gel method. These membranes were fabricated by pressing and sintering at $1300^{\circ}C$ for 6 h. As the amount of yttrium increased, the grain size of the membrane decreased. Hydrogen permeability was improved as the yttrium content increased. Selective permeability of hydrogen compared to CO is explained by electric conductivity. As the temperature rose, both the hydrogen perm-selectivity and electric conductivity on $Ce_{0.8}Y_{0.2}O_{1.9}$ improved.

• 한국세라믹학회지
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• 제55권6호
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• pp.576-580
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• 2018

In this study, a small amount of CoO was added to commercial Gd-doped $CeO_2$ (GDC) powder. The CoO addition greatly enhanced sinterability at low temperatures, i.e., more than 98% of relative density was achieved at $1,000^{\circ}C$. When GDC/8YSZ (8 mol% yttrium stabilized zirconia) bilayers were sintered, Co-doped GDC showed excellent adhesion to the YSZ electrolyte. Transmission electron microscope (TEM) analysis showed that there were no traces of liquid films at the grain boundaries of GDC, whereas liquid films were observed in the Co-doped GDC sample. Because liquid films facilitate particle rearrangement and migration during sintering, mechanical stresses at the interface of a bilayer, which are developed based on different densification rates between the layers, might be reduced. In spite of $Co^{2+}$ doping in GDC, the electrical conductivity was not significantly changed, relative to GDC.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 추계학술발표대회
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• pp.31.1-31.1
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• 2011

$Li_4Ti_5O_{12}$ is emerging as a promising material with its good structure stability and little volume change during the electrochemical reaction. However, its electrochemical performance is significantly limited by low electronic or ionic conductivity. In addition, high tap density is needed forim proving its volumetric energy density and commercialization. To enhance these properties, the spherical-like $Li_4Ti_5O_{12}$ particles were synthesized and carried out doping with yttrium. Prepared Y-doped $Li_4Ti_5O_{12}$ as a anode material showed great capacity retention rate of 92% (5C/0.2C), compared with no dope done. Consequently, it was found that Y doping into $Li_4Ti_5O_{12}$ matrix reduces the polarization and resistance on SEI layer during the electrochemical reaction.

• Bulletin of the Korean Chemical Society
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• 제35권10호
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• pp.2917-2921
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• 2014

Cerium-activated yttrium aluminate ($Y_3Al_5O_{12}:Ce^{3+}$) exhibiting a garnet structure has been widely utilized in the production of light emitting diodes (LEDs) as a yellow emitting phosphor. The commercialized yttrium aluminum garnet (YAG) phosphor is typically synthesized by a solid-state reaction, which produces irregular shape particles with a size of several tens of micrometers by using the top-down method. To control the shape and size of particles, which had been the primary disadvantage of top-down synthetic methods, we synthesized YAG:Ce nanoparticles with a diameter of 500 nm using a coprecipitation method under the atmospheric pressure without the use of template or special equipment. The precursor particles were formed by refluxing an aqueous solution of the nitrate salts of Y, Al, and Ce, urea, and polyvinylpyrrolidone (55 K) at $100^{\circ}C$ for 12 h. YAG:Ce nanoparticles were formed by the calcination of precursor particles at $1100^{\circ}C$ for 10 h under atmospheric conditions. The phase identification, microstructure, and photoluminescent properties of the products were evaluated by X-ray powder diffraction, scanning electron microscopy, absorption spectrum and photoluminescence analyses.

• E2M - 전기 전자와 첨단 소재
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• 제6권3호
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• pp.214-219
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• 1993

고온에서 실리콘에 인을 확산시키기 위한 새로운 고체 판상 원료를 개발하였다. Source Wafer는 거품 형태의 골결을 지닌 불활성 재료에 Yttrium metaphosphate가 들어있는 구조로 되어있다. 새로운 고체 판상 원료를 사용하여 고온에서 인을 확산시켜서 재현 가능한 Sheet resistance와 깊은 Junction을 얻었다. 일련의 한 시간 도핑 결과들로부터 새로운 고체 판상 원료의 수명은 40시간 이상인 것으로 판명되었다. 1150.deg.C에서 인의 실리콘에로의 확산에 대한 유효 확산계수와 대응되는 활성화 에너지의 값을 구하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.299-301
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• 1989

This study presents a method of preparing $YBa_2Cu_3O_{7-x}$ ceramic and chlorine doping in it for the purpose of Jc enhancement us ins sol-gel process.Tetramethylammonium-hydroxide and pottasium carbonate solution were added to the aqueous solution of Yttrium nitrate, Barium chloride and Copper nitrate for pH control as well as forming hydroxy-carbonate precipitation. Instead of Barium nitrate, Barium chloride was used for doping chloride impurities in the specimen. The resulted materal showed good high Tc-superconductivity after calcination. Tc and Jc value are 92 K and 120.8 $A/cm^2$ respectively.