• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.421.1-421.1
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• 2016

We studied indium-doped zinc oxide (IZO) film grown by atomic layer deposition (ALD) as transparent conductive oxide (TCO). A variety of TCO layer, such as ZnO:Al (AZO), InSnO2(ITO), Zn (O,S) etc, has been grown by various method, such as ALD, chemical vapor deposition (CVD), sputtering, laser ablation, sol-gel technique, etc. Among many deposition methods, ALD has various advantages such as uniformity of film thickness, film composition, conformality, and low temperature deposition, as compared with other techniques. In this study, we deposited indium-doped zinc oxide thin films using diethyl[bis(trimethylsilyl)amido]indium [Et2InN(TMS)2] as indium precursor, DEZn as zinc precursor and H2O as oxidant for ALD and investigated the optical and electrical properties of IZO films. As an alternative, this liquid In precursor would has several advantages in indium oxide thin-film processes by ALD, especially for low resistance indium oxide thin film and high deposition rate as compared to InCp, InCl3, TMIn precursors etc. We found out that Indium oxide films grown by Et2InN(TMS)2 and H2O precursor show ALD growth mode and ALD growth window. We also found out the different growth rate of Indium oxide as the substrate and investigated the effect of the substrate on Indium oxide growth.

• Journal of the Korean Ceramic Society
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• v.31 no.1
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• pp.1-10
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• 1994

Monodispersed alumina and Mg-doped alumina fine particles were prepared by controlled hydrolysis of alkoxides. Aluminium alkoxide and magnesium alkoxide were dissolved into complex solvent which was composed of hydrophobic n-octanol and hydrophilic acetonitrile. Hydroxypropyl cellulose(HPC) was used as a dispersant for the alumina particles. The size of these prepared powders was approximately 0.3 ${\mu}{\textrm}{m}$. In the case of sintering above 100$0^{\circ}C$, most of these prepared powders were transformed to $\alpha$-alumina. The relative density of the sintered body of these prepared powders at 1$600^{\circ}C$ was 98%. The sintered body of the Mg-doped alumina powder had more uniform grain size than that of the undoped alumina podwer.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.51.1-51.1
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• 2010

$Y_2O_3$ $Er_2O_3$ and $Nd_2O_3$ doped polycrystalline silicon nitride were prepared by hot pressed sintering at $1850^{\circ}C$ and their optical transmittance were investigated in visible and in infrared region. Mechanical and tribological properties were also investigated. Grain growth in silicon nitride was reduced with addition of $Y_2O_3$ and $Nd_2O_3$. 1 wt.% of each rare earth metal were sintered with 3 wt.% MgO, 9wt.% AlN and 87 wt.% of ${\alpha}-Si_3N_4$. Adding these rare earth metal oxides shows good mechanical properties as high strength and toughness and also shows low friction coefficient.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.6
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• pp.372-375
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• 2017

ZnO thin films were deposited by RF magnetron sputtering and then diffused by using an As source in the ampouletube. Also, the ZnO p-n homojunction was made by using As-doped ZnO thin films, and its properties were analyzed. After the As doping, the surface roughness increased, the crystal quality deteriorated, and the full width at half maximum was increased. The As-doped ZnO thin films showed typical p-type properties, and their resistivity was as low as $2.19{\times}10^{-3}{\Omega}cm$, probably because of the in-diffusion from an external As source and out-diffusion from the GaAs substrate. Also, the ZnO p-n junction displayed the typical rectification properties of a p-n junction. Therefore, the As diffusion method is effective for obtaining ZnO films with p-type properties.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.57.2-57.2
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• 2010

투명전도 산화막(Transparent conducing oxide: TCO)은 태양 전지, 터치패널, 가스 센서 등 여러 분야에 적용할 수 있는 물질로서 전기 전도성과 광 투과성을 동시에 가진다. 높은 전기 전도성과 광 투과성을 가지는 Sb:$In_2O_3$(ITO)는 투명전도 산화막 재료로써 가장 일반적으로 사용되고 있으나 인듐의 매장량 한계로 인해 가격이 높다는 단점이 있다. 본 연구에서는 ITO 대체 TCO 물질인 Al doped ZnO(AZO)를 rf magnetron sputter를 이용하여 최적의 수소 도핑량을 찾아 ITO의 전기적 광학적 성질과 비교하였다. AZO 박막은(ZnO:Al2O3 2wt.%)타겟을 이용하여 heater 온도 250도에서 슬라이드 글래스 및 코닝 글래스에 증착시켰고 비교군인 ITO박막은 (In2O3:$SnO_2$ 10wt.%)타겟을 이용하여 수소 도핑 없이 350도로 증착시켰다. AZO 및 ITO 박막의 전기적 특성은 hall measurement를 이용하여 측정하였고, UV-VIS spectrophotometer로 광학적 특성을 측정하였다. 수소 도핑량이 증가함에 따라 AZO 박막의 캐리어 농도가 증가하여 전기적 특성이 향상되었고, 가시광 영역에서 높은 평균 투과도를 유지 하였다. AZO 박막과 ITO 박막의 전기적 및 광학적 특성을 비교한 결과, 최적 수소 도핑량을 가진 AZO 박막은 ITO 박막에 준하는 특성을 보였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.1057-1061
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• 2007

In this study, we investigated the properties of ZnO thin films prepared by layer-by-layer method in RF magnetron sputtering system using AlAs and ZnO targets. Effects of $H_2O_2$ dip prior to thermal treatment were studied as well. Either n-type or p-type films were observed in our study depending on the annealing conditions. It thus indicates the feasibility of arbitrarily modifying the conductivity type. At the same time, it also implies the thermal instabilities of the film properties. Property measurements after stressing the films up to 144 hours showed that thermal variations of properties nay be suppressed by pre-treatment in 30% $H_2O_2$ for 1 min.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1555-1562
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• 2015

Metal oxide semiconductors have been applied in several areas, such as solar cells, sensor, optical elements and displays, due to the high surface area, unique electrical and optical characteristics. Zinc oxide among the metal oxide has excellent physicochemical properties. Zinc oxide is a n-type semiconductor with a wide direct transition band gap of 3.37 eV at room temperature and large exciton binding energy of 60 meV. Cation-doped zinc oxide studies were conducted to complement the electrical and optical characteristics. In this paper, Al-doped ZnO was synthesized by hydrothermal synthesis using microwaves. ZnO was synthesized by adjusting the precursor ratio and using different dopants. The optimal ZnO synthesis conditions for crystal shape and optical properties were determined. The optical properties of aluminum doped zinc oxide were then examined by SEM, XRD, PL, UV-vis absorbance spectrum, and EDS.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.12
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• pp.1283-1288
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• 2004

Metal-ferroelectric-insulator-semiconductor(WFIS) capacitors using rapid thermal annealed LiNbO$_3$/AlN/Si(100) structure were fabricated and demonstrated nonvolatile memory operations. The capacitors on highly doped Si wafer showed hysteresis behavior like a butterfly shape due to the ferroelectric nature of the LiNbO$_3$ films. The typical dielectric constant value of LiNbO$_3$ film in the MFIS device was about 27, The gate leakage current density of the MFIS capacitor was 10$^{-9}$ A/cm$^2$ order at the electric field of 500 kV/cm. The typical measured remnant polarization(2P$_{r}$) and coercive filed(Ec) values were about 1.2 $\mu$C/cm$^2$ and 120 kV/cm, respectively The ferroelectric capacitors showed no polarization degradation up to 10$^{11}$ switching cycles when subjected to symmetric bipolar voltage pulses of 1 MHz. The switching charges degraded only by 10 % of their initial values after 4 days at room temperature.e.

• Journal of the Korean Ceramic Society
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• v.53 no.4
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• pp.463-467
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• 2016

$Si^{4+}-N^{3-}$ was incorporated into $Ce^{3+}-doped$ lutetium aluminum garnet ($Lu_{2.965}Ce_{0.035}Al_5O_{12}$, $LuAG:Ce^{3+}$) lattices, resulting in the formation of $Lu_{2.965}Ce_{0.035}Al_{5-x}Si_xO_{12-x}N_x$ [(Lu,Ce)AG:xSN]. For x = 0-0.25, the synthesized powders consisted of the LuAG single phase, and the lattice constant decreased owing to the smaller $Si^{4+}$ ions. However, for x > 0.25, a small amount of unknown impurity phases was observed, and the lattice constant increased. Under 450 nm excitation, the PL spectrum of $LuAG:Ce^{3+}$ exhibited the green band, peaking at 505 nm. The incorporation of $Si^{4+}-N^{3-}$ into the $Al^{3+}-O^{2-}$ sites of $LuAG:Ce^{3+}$ led to a red-shift of the emission peak wavelength from 505 to 570 nm with increasing x. Corresponding CIE chromaticity coordinates varied from the green to yellow regions. These behaviors were discussed based on the modification of the $5d^1$ split levels and crystal field surroundings of $Ce^{3+}$, which arose from the Ce-(O,N)8 bonds.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.88-88
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• 2011

ZnO는 직접 천이형 반도체로써, 상온에서 3.4eV에 해당하는 띠틈을 가지고 있다. 뿐만 아니라 60meV의 큰 엑시톤 결합에너지를 가지고 있어 단파장 광전 소자 영역의 LED(Light Emitting Diode)나 LD(Laser Diode)에 널리 사용되고 있다. 하지만 일반적으로 격자틈새 Zn(Zni2+)이온이나 O 빈자리(V02+)이온과 같은 자연적인 도너 이온이 존재하여 n-형 전도성을 나타낸다. 그러므로 ZnO계 LED와 LD의 개발에 있어서 가장 중요한 연구 과제는 재현성 있고 안정된 고농도의 p-형 ZnO박막을 성장시키는 것이다. 하지만, 자기보상효과나 얕은 억셉터 준위, 억셉터의 낮은 용해도로 인하여 어려움을 가지고 있다. 본 연구에서는 고품질의 p-형 ZnO박막을 제작하기 위해 AlN를 도핑시킨 ZnO박막을 RF 마그네트론 스퍼터링 법을 이용하여 Ar과 O2분위기에서 성장시켰다. ZnO와 AlN타겟을 동시에 사용하였으며, ZnO타겟에 걸어준 RF 파워는 80W, AlN타겟에 걸어준 RF 파워는 5~20W로 변화시켰다. 박막의 전기적, 광학적 특성은 XPS (X-ray Photoelectron Spectroscopy), REELS (Reflection Electron Energy Loss Spectroscopy), XRD (X-ray Diffraction), SIMS (Secondary Ion Mass Spectrometry), AES (Auger Electron Spectroscopy), Hall measurement를 이용하여 연구하였다. XPS측정결과, AlN를 도핑시킨 ZnO박막의 Zn2p3/2와 O1s피크는 undoped ZnO박막의 피크보다 낮은 결합에너지에서 측정되었다. 모든 박막이 결정화 되었으며, (002)방향으로 우선적으로 성장된 것을 확인할 수 있었다. 홀 측정 결과, 기판을 $200^{\circ}C$로 가열하면서 성장시킨 박막이 p-형을 나타내었으며, 비저항(Resistivity)이 $5.51{\times}10^{-3}{\Omega}{\cdot}m$, 캐리어 농도(Carrier Concentration)가 $1.96{\times}1018cm^{-3}$, 이동도(Mobility)가 $481cm^2$/Vs이었다. 또한 QUEELS -Simulation에 의한 광학적 특성분석 결과, 가시광선영역에서 투과율이 90%이상으로 투명전자소자로의 응용이 가능하다는 것을 보여주었다.