• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.25-28
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• 2001

The objectives of this paper are to demonstrate the electrical degradation phenomena with Si atom's behaviors in the grainboundary of semiconducting ZnO ceramics. The ZnO ceramic devices used in this investigation were fabricated by standard ceramic techniques. Especially, $SiO_2$ were added to analyze the degradation characteristics with Si and sintered in oxygen ambient at $1300^{\circ}C$. The conditions of DC degradation test were $115{\pm}2^{\circ}C$ for 13h. Using XRD and SEM, the phase and microstructure of samples were analyzed respectively. E-J analysis was used to determine $\alpha$. Frequency analysis was accomplished to understand $R_g$ and $R_b$ at the equivalent circuit. Electrical stability improved as the amount of $SiO_2$ addition increased. This results were explain by the quantitative analysis and the line scanning method of EPMA.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.205-205
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• 2015

최근, 비정질 산화물 반도체를 이용한 TFT는 투명성, 유연성, 저비용, 저온공정이 가능하기 때문에 차세대 flat-panel 디스플레이의 back-plane TFT로써 다양한 방면에서 연구되고 있다. 산화물 반도체 In-Zn-O-시스템에서는 Gallium (Ga)을 suppressor로 사용한 a-In-Ga-Zn-O (a-IGZO) 뿐만 아니라, Magnesium (Mg), Hafnium (Hf), Tin (Sn), Zirconium (Zr) 등의 다양한 물질이 연구되었다. 그 중 Silicon (Si)은 Ga, Hf, Sn, Zr, Mg과 같은 suppressor에 비해 구하기 쉬우며 가격적인 측면에서도 저렴하다는 장점이 있다. solution 공정으로 제작한 산화물 반도체 TFT는 진공 시스템을 사용한 공정보다 공정시간이 짧고, 저비용, 대면적화가 가능하다는 장점이 있다. 하지만, 투명하고 유연한 device를 제작하기 위해서는 저온 공정과 low thermal budget은 필수적이다. 이러한 측면에서 MWI (Microwave Irradiation)는 저온공정이 가능하며, 짧은 공정 시간에도 불구하고 IZO 시스템의 산화물 반도체의 전기적 특성 향상을 기대할 수 있는 효율 적인 열처리 방법이다. 본 연구에서는 In-Zn-O 시스템의 TFT에서 silicon (Si)를 Suppressor로 사용한 a-Si-In-Zn-O (SIZO) TFT를 제작하여 두 가지 열처리 방법을 사용하여 TFT의 전기적 특성을 확인하였다. 첫 번째 방법은 Box Furnace를 사용하여 N2 분위기에서 $600^{\circ}C$의 온도로 30분간 열처리 하였으며, 두 번째는 MWI를 사용하여 1800 W 출력 (약 $100^{\circ}C$)에 2분간 열처리 하였다. MWI 열처리는 Box Furnace 열처리에 비해 저온 공정 및 짧은 시간에도 불구하고 향상된 전기적 특성을 확인 할 수 있었다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.5
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• pp.349-352
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• 2012

ZnO thin films were deposited on a-, c- and m- plane oriented 4H-SiC substrates by pulsed laser deposition. ZnO nanowires were formed on substrates by tube furnace. Shape and density of the ZnO nanowires were investigated by field emission scanning electron microscope. Average surface roughness and root mean square surface roughness were measure by atomic force microscope. Optical properties were investigated by Photoluminescence measurement. Density of ZnO nanowires grown on a-, c- and m-plane oriented 4H-SiC substrates were 17.89 ${\mu}m^{-2}$, 9.98 ${\mu}m^{-2}$ and 2.61 ${\mu}m^{-2}$, respectively.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.3
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• pp.15-19
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• 2003

In This paper, we developed 1.96 GHz air gap type FBAR BPF using ZnO as piezoelectric sputtered by RF magnetron at room temperature. FBAR BPF was fabricated by sputtering bottom electrode (Al), ZnO as piezoelectric and top electrode (Mo) on Si wafer one by one with RF magnetron sputter, then Si was dry etched to make an air hole. XRD test result of fabricated FBAR BPF showed that ZnO crystal was well pre-oriented as (002) and sigma value of XRC was 1.018. IL(Insertion loss) showed excellent result as 1 dB.

• Korean Journal of Materials Research
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• v.23 no.10
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• pp.580-585
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• 2013

To observe the formation of defects at the interface between an oxide semiconductor and $SiO_2$, ZnO was prepared on $SiO_2$ with various oxygen gas flow rates by RF magnetron sputtering deposition. The crystallinity of ZnO depends on the characteristic of the surface of the substrate. The crystallinity of ZnO on a Si wafer increased due to the activation of ionic interactions after an annealing process, whereas that of ZnO on $SiO_2$ changed due to the various types of defects which had formed as a result of the deposition conditions and the annealing process. To observe the chemical shift to understand of defect deformations at the interface between the ZnO and $SiO_2$, the O 1s electron spectra were convoluted into three sub-peaks by a Gaussian fitting. The O 1s electron spectra consisted of three peaks as metal oxygen (at 530.5 eV), $O^{2-}$ ions in an oxygen-deficient region (at 531.66 eV) and OH bonding (at 532.5 eV). In view of the crystallinity from the peak (103) in the XRD pattern, the metal oxygen increased with a decrease in the crystallinity. However, the low FWHM (full width at half maximum) at the (103) plane caused by the high crystallinity depended on the increment of the oxygen vacancies at 531.66 eV due to the generation of $O^{2-}$ ions in the oxygen-deficient region formed by thermal activation energy.

• Journal of Information Display
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• v.1 no.1
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• pp.35-41
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• 2000

Manganese-doped $Zn_2SiO_4$ phosphors well known as a green emitter with high luminescence efficiency were prepared by the homogeneous precipitation method, and their photoluminescence properties under vacuum-ultraviolet (VUV) excitation were investigated. $Zn_2SiO_4$:Mn phosphors obtained by this method have exhibited a high luminance of property and a spherical shape of particles. In particular, the green emission intensity of zinc orthosilicate prepared as containing around 2 mole% of manganese was much stronger than that of the commercial $Zn_2SiO_4$:Mn phosphor, while the decay time was longer. However, addition of $Al^{3+}$ and $Li^+$ into $Zn_2SiO_4$:Mn composition has significantly diminished the decay time of the phosphor without much degradation of the emission intensity.

• Transactions on Electrical and Electronic Materials
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• v.8 no.3
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• pp.121-124
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• 2007

The $Zn_2SiO_4:Mn$ phosphors were prepared using polymer matrix technique in order to improve the performance of green emitting phosphors for plasma display panel(PDP). $Zn_2SiO_4:Mn$ phosphor exhibits a strong green emission around 520-530 nm. The emission intensity and particle size of powders were controlled by sintering temperature and raw material composition. The zinc silicate $Zn_2SiO_4:Mn$ single phase were obtained at lower temperature than prepared by solid-state reaction method. PL luminance of $Zn_2SiO_4:Mn$ phosphor was similar to the commercial material.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.2
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• pp.71-75
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• 2014

To observe the optical characteristic of oxide semiconductor depending on the degree of bonding structures, SiOC, ZnO and IGZO were prepared by the RF magnetron sputter system and chemical vapor deposition. Generally, crystal ZnO, amorphous SiOC and IGZO changed the optical characteristics in according to the electro-chemical behavior due to the oxygen vacancy at an interface between different groups. Transmittance of SiOC and IGZO with amorphous structures was higher than that of ZnO with crystal structure, because of lowering the carrier concentration due to the recombination of electron and holes carriers as oxygen vacancies. Besides, the energy gap of amorphous SiOC and IGZO was higher than the energy gap of crystal ZnO. The diffusion mobility of holes is higher than the drift mobility of electrons.

• Journal of the Korean Ceramic Society
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• v.28 no.6
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• pp.471-477
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• 1991

Effects of ZnO, PbO and SiO2 on the grain growth and magnetic properties of Sr-ferrite were investigated. (1) Addition of ZnO to Sr-ferrite increased remanence, but decreased coercivity and maximum energy product. (2) Addition of PbO up to 0.5 wt% increased (B$.$H)max of Sr-ferrite, but addition more than 0.5 wt% decreased (B$.$H)mzx (3) SiO2 addition to the 0.5 wt% PbO doped Sr-ferrite decreased remanence and increased coercivity. The coercivity increase in due to the grain refinement effect of SiO2. But addition of SiO2 more than 0.5 wt% invoked a decrease of coercivity and (B$.$H)max of Sr-ferrite due to abnormal grain growth. Sr-ferrite magnet having maximum energy product of 3.7MGOe was fabricated by using the roasting product of Pyrrhotite.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.26.1-26.1
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• 2011

We investigated the atomic layer deposition (ALD) process for nitrogen doped ZnO and the application for n-ZnO : N/p-Si (NW) coaxial hetero-junction photodetectors. ALD ZnO:N was deposited using diethylzinc (DEZ) and diluted $NH_4OH$ at $150^{\circ}C$ of substrate temperature. About 100~300 nm diameter and 5 um length of Si nanowires array were prepared using electroless etching technique in 0.108 g of $AgNO_3$ melted 20 ml HF liquid at $75^{\circ}C$. TEM images showed ZnO were deposited on densely packed SiNW structure achieving extraordinary conformality. When UV (360 nm) light was illuminated on n-ZnO:N/p-SiNW, I-V curve showed about three times larger photocurrent generation than film structure at 10 V reverse bias. Especially, at 660 nm wave length, the coaxial structure has 90.8% of external quantum efficiency (EQE) and 0.573 A/W of responsivity.