• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2004년도 춘계총회 및 연구발표회 초록집
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• pp.47.3-47.3
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• 2004

• 한국재료학회지
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• 제28권2호
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• pp.101-107
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• 2018

Li-incorporated ZnO thin films were deposited by using ultrasonic-assisted spray pyrolysis deposition (SPD) system. To investigate the effect of Li-incorporation on the performance of ZnO thin films, the structural, electrical, and optical properites of the ZnO thin films were analyzed by means of X-ray diffraction (XRD), field-emssion scanning electron microscopy (FE-SEM), Hall effect measurement, and UV-Vis spectrophotometry with variation of the Li concentraion in the ZnO sources. Without incorporation of Li element, the ZnO surface showed large spiral domains. As the Li content increases, the size of spiral domains decreased gradually, and finally formed mixed small grain and one-dimensional nanorod-like structures on the surface. This morphological evolution was explained based on an anti-surfactant effect of Li atoms on the ZnO growth surface. In addition, the Li-incorporation changed the optical and electrical properties of the ZnO thin films by modifying the crystalline defect structures by doping effects.

• 한국재료학회지
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• 제28권9호
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• pp.516-521
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• 2018

Copper oxide thin films are deposited using an ultrasonic-assisted spray pyrolysis deposition (SPD) system. To investigate the effect of substrate temperature and incorporation of a chelating agent on the growth of copper oxide thin films, the structural and optical properites of the copper oxide thin films are analyzed by X-ray diffraction (XRD), field-emssion scanning electron microscopy (FE-SEM), and UV-Vis spectrophotometry. At a temperature of less than $350^{\circ}C$, three-dimensional structures consisting of cube-shaped $Cu_2O$ are formed, while spherical small particles of the CuO phase are formed at a temperature higher than $400^{\circ}C$ due to a Volmer-Weber growth mode on the silicon substrate. As a chelating agent was added to the source solutions, two-dimensional $Cu_2O$ thin films are preferentially deposited at a temperature less than $300^{\circ}C$, and the CuO thin film is formed even at a temperature less than $350^{\circ}C$. Therefore the structure and crystalline phase of the copper oxide is shown to be controllable.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.107-110
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• 1999

The ultrasonic spray method was employed to make (Y,Gd)BO$_3$:Eu Phosphor, and its optical properties under 147nm VUV and 254 nm UV excitations were characterized and then compared with that produced by the solid-state reaction. The mixed solution of acetate hydrates of Y, Gd, Eu and boric acid diluted in water or methanol was used as the precursor fur the spray. It was found that (Y,Gd)BO$_3$:Eu phosphor made by this ultrasonic spray had a spherical shape and fine particle size of 1${\mu}{\textrm}{m}$. The crystalline structure for the as-sprayed phosphor was amorphous, but it converted into the same polycrystalline phase of solid state reaction after post heat treatment at 110$0^{\circ}C$ for 2hr. The emitting intensity under VUV and UV excitations for the spray-formed (Y,Gd)BO$_3$:Eu phosphor, however, was inferior to the later one. The excitation spectra were also studied and compared under VUV and UV excitations to explain the change of emitting intensity with Gd substitution in (Y$_{1-x}$ Gd$_{x}$)BO$_3$:Eu Phosphors made by spray and solid state reaction.on.

• Progress in Superconductivity
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• 제13권2호
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• pp.127-132
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• 2011

Many research groups have been manufacturing coated conductor by various processes such as PLD, MOD, and MOCVD, but the methods with production cost suitable for wide and massive application of coated conductor did not develop yet. Spray pyrolysis method adopting ultrasonic atomization was tried as one of the possible option. GdBCO precursor films have been deposited on IBAD substrate by spray pyrolysis method at low temperature and converted to GdBCO by post heat treatment. Ultrasonic atomization was used to generate fine droplets from precursor solution of Gd, Ba, and Cu nitrate dissolved in water. Primary GdBCO films were deposited at $500^{\circ}C$ and oxygen partial pressure of 1 torr. After that, the films were converted at various temperatures and low oxygen partial pressures. C-Axis oriented films were obtained IBAD substrates at conversion temperature of around $870^{\circ}C$ and oxygen partial pressures of 500 mtorr ~ 1 torr in a vacuum. Thick c-axis epitaxial film with the thickness of 0.4 ~ 0.5 ${\mu}m$ was obtained on IBAD substrate. C-axis epitaxial GdBCO films were successfully prepared by ex-situ methods using nitrate precursors on IBAD metal substrate. Converted GdBCO films have very dense microstructures with good grain connectivity. EDS composition analysis of the film showed a number of Cu-rich phase in surface. The precursor solution having high copper concent with the composition of Gd : Ba : Cu = 1 : 2 : 4 showed the better grain connectivity and electrical conductivity.

• 한국분말재료학회지
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• 제26권1호
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• pp.34-39
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• 2019

Current synthesis processes for titanium dioxide ($TiO_2$) nanoparticles require expensive precursors or templates as well as complex steps and long reaction times. In addition, these processes produce highly agglomerated nanoparticles. In this study, we demonstrate a simple and continuous approach to synthesize $TiO_2$ nanoparticles by a salt-assisted ultrasonic spray pyrolysis method. We also investigate the effect of salt content in a precursor solution on the morphology and size of synthesized products. The synthesized $TiO_2$ nanoparticles are systematically characterized by X-ray diffraction, transmission electron micrograph, and UV-Vis spectroscopy. These nanoparticles appear to have a single anatase phase and a uniform particle-size distribution with an average particle size of approximately 10 nm. By extrapolating the plots of the transformed Kubelka-Munk function versus the absorbed light energy, we determine that the energy band gap of the synthesized $TiO_2$ nanoparticles is 3.25 eV.

• 한국진공학회지
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• 제19권1호
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• pp.66-71
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• 2010

PDP를 비롯한 형광체를 이용하는 디스플레이 분야에서 현재 마이크로미터($\mu}$-meter) 이상의 크기를 갖는 기존의 벌크(bulk) 형광체를 능가하는 성능과 새로운 물성을 나타내는 나노형광체(nanophosphor) 개발 및 응용에 대한 연구가 절대적으로 필요한 시점이다. 따라서 본 실험에서는 나노 사이즈의 평균 입자 크기를 갖는 구형의 $Zn_2SiO_4:Mn$ 형광체 입자를 초음파 분무열 분해(ultrasonic spray pyrolysis) 방법을 이용하여 합성하였다. 구형의 형광체 입자의 크기는 분무 장치의 droplet separator를 도입하여 조절하였다. 2 mol%의 망간을 도핑하여 합성한 $Zn_2SiO_4:Mn$ 입자는 시간이 지남에 따라 감소되고, 최근에 고상에서 합성하여 상용화된 물질에 비교할 수 있을 만한 빛 방출의 세기를 가졌다. 형광체 입자의 크기는 무기질 염의 농도가 0에서 5 M로 증가함에 따라 $1\;{\mu}m$에서 $0.2\;{\mu}m$로 감소하였다. 0.5 M 이상의 농도의 전구체 용액에서 얻어진 형광체 입자의 빛 방출은 상용화되어 있는 물질과의 비교를 통해 알아보았다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2004년도 춘계학술강연 및 발표대회 강연 및 발표논문 초록집
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• pp.63-64
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• 2004

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.283-286
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• 1999

Transparent conductive aluminum-doped ZnO(AZO) films Were prepared by a ultrasonic spray pyrolysis method at the substrate temperature below 23$0^{\circ}C$. A vertical type hot wall furnace was used as a reactor in the deposition system. Zinc acetate dissolved in methanol was selected as a precursor. The substrate temperature was varied from 18$0^{\circ}C$to 24$0^{\circ}C$. Aluminum (Al) was doped into ZnO films by incorporating anhydrous aluminum chloride (AlCl$_3$) in the zinc acetate solution. The proportion of the Al in the starting solution was varied from 0 wt % to 3.0 wt %. The crystallographic properties and surface morphologies of the films were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The resistivity of the films was measured by the Van der Pauw method, and the mobility and carrier concentration were obtained through the Hall effect measurements Transmittance was measured in the visible region. The effects of substrate temperature and aluminum content in the starling solution on the structural and electrical properties of the AZO films are discussed

• 멤브레인
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• 제15권2호
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• pp.105-113
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• 2005

표면 개질한 다공성 금속 지지체에 초음파 분무 열분해법을 이용하여 silica막을 합성하고, 고온 기체 선택 투과 분리 특성을 조사하였다. Tetraethyl orthosilicate (TEOS)를 전구체로 하여 지지체 세공을 통한 감압 진공을 하면서 873K에서 표면에 defect 없이 균일한 양질의 silica막이 형성되었다. 투과 온도 523 K에서 silica막의 수th/질소 및 수증기/메탄을 분리 계수가 각각 17 및 16 정도의 우수한 선택 투과 성능을 나타냈다. 다공성 금속 지지체의 불균일한 기공에 silica 분체 및 $\gamma-alumina$층을 중간층으로 도입하고, 그 위에 열분해법에 의한 silica를 합성한 결과, Knudsen 확산에 의한 투과 영역의 세공이 완전히 제거되어 높은 수소 및 수증기 선택성을 가지는 복합 막이 형성되었다.