• 한국전기전자재료학회논문지
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• 제17권6호
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• pp.586-591
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• 2004

We studied the dependence of hot-tarrier-induced degradation characteristics on nitrogen concentration in NO(Nitrided-Oxide) gate of nMOS, under ac and dc stresses. The $\Delta$V$_{t}$ and $\Delta$G$_{m}$ dependence of nitrogen concentration were observed, We observed that device degradation was suppressed significantly when the nitrogen concentration in the gate was increased. Compared to $N_2$O oxynitride, NO oxynitride gate devices show a smaller sensitivity to ac stress frequency. Results suggest that the improved at-hot carrier immunity of the device with NO gate may be due to the significantly suppressed interface state generation and neutral trap generation during stress.ess.

• 한국재료학회지
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• 제7권3호
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• pp.213-217
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• 1997

200MHz 응향광변조기 (AOM: Acousto-Optic Modulator)는 제 2고조파(SHG: Second Harmonic Generation)녹색 레이저와 함께 DVDR(Digital Video Disk Recorder)에 적용되어 고밀도 광기록용으로 사용되었다. 이러한 고밀도 광기록 장치로써 사용되기 위해서는 고출력 레이저의 사용이 필수적이며, 레이저 빔이 통과하는 각 광학 소자들의 코팅막은 고출력 레이저 빔에 대해 높은 레이저 damage threshold를 가져야 한다. AOM의 음향공학재료로 사용되는 $TeO_{2}$단결정에 코팅막의 종류 및 증착조건을 변화시키며 E-beam 증착법으로 A/R코팅 시편을 준비하였다. 0.55W의 입력 power를 갖는Ar레이저를 사용하여 코팅의 광손상 정도를 확인하였다. $AI_{2}O_{3}$막에 비해 $ZrO_{2}$와 $SiO_{2}$막을 사용한 경우 레이저 damage threshold는 크게 향상되었다. 또한 AOM모듈을 제작 후 구동회로와 연결하여 약 20mW의 SHG power를 입력시키며 출력 power long term안정성을 측정하였다.

• 한국전기전자재료학회논문지
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• 제18권11호
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• pp.1043-1047
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• 2005

To investigate the electrical properties of the ZnO films which are interested in the next generation of short wavelength LEDs and Lasers, our ZnO thin films were deposited by RF sputtering system. At sputtering process of ZnO thin films, substrate temperature, work pressure respectively is $300^{\circ}C$ and 5.2 mTorr, and the purity of target is ZnO 5N. The thickness of ZnO thin films was about $2.1\;{\mu}m$ at SEM analysis after sputtering process. Phosphorus (P) and arsenic (As) were diffused into the undoped ZnO thin films sputtered by RF magnetron sputtering system in ampoule tube which was below $5\times10^{-7}$ Torr. The dopant sources of phosphorus and arsenic were $Zn_3P_2$ and $ZnAs_2$. Those diffusion was perform at 500, 600, and $700^{\circ}C$ during 3 hr. We found the diffusion condition of the conductive ZnO films which had n- and p-type properties. Our ZnO thin film has not only very high carrier concentration of above $10^{17}/cm^3$ but also low resistivity of below $2.0\times10^{-2}\;{\Omega}cm$.

• Transactions on Electrical and Electronic Materials
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• 제4권5호
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• pp.33-37
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• 2003

This study was performed to investigate the deposition mechanism of SiO$_2$ by ArF excimer laser(l93nm) CVD with Si$_2$H$\_$6/ and N$_2$O gas mixture and evaluate laser CVD quantitatively by modeling. With ArF excimer laser CVD, thin films can be deposited at low temperature(below 300$^{\circ}C$), with less damage and good uniformity owing to generation of conformal reaction species by singular wavelength of the laser beam. In this study, new model of SiO$_2$ deposition process by laser CVD was introduced and deposition rate was simulated by computer with the basis on this modeling. And simulation results were compared with experimental results measured at various conditions such as reaction gas ratio, chamber pressure, substrate temperature and laser beam intensity.

• Journal of Electrochemical Science and Technology
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• 제14권3호
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• pp.231-242
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• 2023

Li₂O-based cathodes utilizing oxide-peroxide conversion are innovative next-generation cathodes that have the potential to surpass the capacity of current commercial cathodes. However, these cathodes are exposed to severe cathode-electrolyte side reactions owing to the formation of highly reactive superoxides (O^x-, 1 ≤ x < 2) from O^2- ions in the Li₂O structure during charging. Succinonitrile (SN) has been used as a stabilizer at the cathode/electrolyte interface to mitigate cathode-electrolyte side reactions. SN forms a protective layer through decomposition during cycling, potentially reducing unwanted side reactions at the interface. In this study, a composite of Li₂O and Ni-embedded reduced graphene oxide (LNGO) was used as the Li₂O-based cathode. The addition of SN effectively thinned the interfacial layer formed during cycling. The presence of a N-derived layer resulting from the decomposition of SN was observed after cycling, potentially suppressing the formation of undesirable reaction products and the growth of the interfacial layer. The cell with the SN additive exhibited an enhanced electrochemical performance, including increased usable capacity and improved cyclic performance. The results confirm that incorporating the SN additive effectively stabilizes the cathode-electrolyte interface in Li₂O-based cathodes.

• 한국유기농업학회지
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• 제9권1호
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• pp.17-27
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• 2001

To clarify the proper and safe duration of maturation periods for sawdust-pig manure composts, leaf lettuces were applied with pig manure composts fermented for 15, 30, 45, 60, 75 days and 1 year (control) and cultivated in a plastic house with or without additional PE film tunnel. The changes in physiochemical properties of soil and leaf lettuce growth were measured. Shorter duration of maturation periods enhanced the generation of N $H_3$ gas from the composts and resulted in significant decrease in seed germination, growth and yield of leaf lettuce. Under with and without PE tunnel conditions the concentration of N $H_3$ from compost over 3.8 and 2.1 mg/100g composts, respectively induced growth reduction. In proportion to the increase of maturation duration saw-dust containing pig manure exhibited decrease in C/N ratio, N $H_4^{+}$-N, N $H_4^{+}$N $O_3^{-}$ ratio but increase in N $O_3^{-}$-N contents. In case of applying pig manure compost without PE film tunnel condition the minimum maturation period of pig manure composts for safe leaf growth was 60 days, while minimum 75 days of maturation was required when applied with PE film tunnel. tunnel.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.11-11
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• 2008

ZnO has a very large exciton binding energy (60 meV) as well as thermal and chemical stability, which are expected to allow efficient excitonic emission, even at room temperature. ZnO based electronic devices have attracted increasing interest as the backplanes for applications in the next-generation displays, such as active-matrix liquid crystal displays (AMLCDs) and active-matrix organic light emitting diodes (AMOLEDs), and in solid state lighting systems as a substitution for GaN based light emitting diodes (LEDs). Most of these electronic devices employ the electrical behavior of n-type semiconducting active oxides due to the difficulty in obtaining a p-type film with long-term stability and high performance. p-type ZnO films can be produced by substituting group V elements (N, P, and As) for the O sites or group I elements (Li, Na, and K) for Zn sites. However, the achievement of p-type ZnO is a difficult task due to self-compensation induced from intrinsic donor defects, such as O vacancies (Vo) and Zn interstitials ($Zn_i$), or an unintentional extrinsic donor such as H. Phosphorus (P) doped ZnO thin films were grown on c-sapphire substrates by radio frequency magnetron sputtering with various Ar/ $O_2$ gas ratios. Control of the electrical types in the P-doped ZnO films was achieved by varying the gas ratio with out post-annealing. The P-doped ZnO films grown at a Ar/ $O_2$ ratio of 3/1 showed p-type conductivity with a hole concentration and hole mobility of $10^{-17}cm^{-3}$ and $2.5cm^2/V{\cdot}s$, respectively. X-ray diffraction showed that the ZnO (0002) peak shifted to lower angle due to the positioning of $p^{3-}$ ions with a smaller ionic radius in the $O^{2-}$ sites. This indicates that a p-type mechanism was due to the substitutional Po. The low-temperature photoluminescence of the p-type ZnO films showed p-type related neutral acceptor-bound exciton emission. The p-ZnO/n-Si heterojunction LEO showed typical rectification behavior, which confirmed the p-type characteristics of the ZnO films in the as-deposited status, despite the deep-level related electroluminescence emission.

• 한국전기전자재료학회논문지
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• 제17권11호
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• pp.1246-1251
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• 2004

This paper is investigated about the effect of carrier gas type and the humidity for generating hydrogen gas. The vibration of the water surface is more powerful with increasing applied voltage. In this experimental reactor which is made of multi-needle and plate, the maximum acquired hydrogen production rate is about 3500 ppm. In the experimental result of generating hydrogen gas by non-thermal plasma reactor, the rate of generating hydrogen gas is different with what kind of carrier gas is. We used two types of carrier gas, such as $N_2$ and He. $N_2$ as carrier gas is more efficient to generate hydrogen gas than He because $N_2$ is reacted with $O_2$, which is made from water dissociation. In comparison with water droplet by humidifier and without water droplet by humidifier, the generation of hydrogen gas is decreased in case of water droplet by humidifier. That is the result that the energy for water dissociation is reduced on water surface because a part of plasma energy is absorbed at the small water molecular produced from humidifier.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.215-219
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• 2004

This paper is investigated about the effect of carrier gas and humidity for generating hydrogen gas. In the experimental result of generating hydrogen gas by non-thermal plasma reactor, the rate of generating hydrogen gas is different with what kind of carrier gas is. We used two types of carrier gas, such as $N_2$ and He. $N_2$ as carrier gas is more efficient to generate hydrogen gas than He because $N_2$ is reacted with $O_2$, which is made from water dissociation. In comparison with no humidity and humidity 45[%], the generation of hydrogen gas is decreased with increasing the humidity. That is the result that the energy for water dissociation is reduced on water surface because a part of plasma energy is absorbed at the small particle produced from humidifier.

• 한국세라믹학회지
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• 제44권4호
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• pp.194-197
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• 2007

Polyacrylonitrile (PAN)/$Fe_2O_3$ nanocomposite membranes with a thickness of 0.02 mm were electrospun by adding 0 to 5 wt% of $Fe_2O_3$ into PAN. The surface tension, density, kinematic viscosity and dynamic viscosity of the PAN solution were determined to be $33.8{\pm}1mN/m$, 0.9794 g/ml, $1548.6mm^2/sec$ and 1516.7 cP, respectively. The average diameters of PAN fibers containing 0, 1 2, 3, and 4 wt% $Fe_2O_3$ particles were 300, 260, 210, 130, and 90 nm, respectively. Fourier-transform infrared spectroscopy results showed that the addition of $Fe_2O_3$ nanoparticles to the PAN mat reduced the absorption peak intensity at $2242cm^{-1}$ ($C{\equiv}N$ bond) while it caused a sharp increase in the peak intensity at $2356cm^{-1}$(C=O bond). Thus, it appears that an appropriate amount of $Fe_2O_3$ nanoparticles in the PAN backbone leads to an improvement of the performance of the $CO_2$ gas sensor, most likely due to the change of functional groups in the membrane.