• 한국포장학회지
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• 제8권1호
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• pp.15-22
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• 2002

PET $16{\mu}m/dry$ lamination/Al-foil $7{\mu}m/dry$ lamination/CPP $80{\mu}m$의 사양으로 2개 업체에서 제조된 포장용 복합필름에서 제품 충전공정 중에서 발생한 열접착 트러블의 원인을 규명하고자 복합필름을 분리하여 각각의 두께와 재질이 제시된 사양과 일치하는지를 관능검사와 IR, DSC로 측정한 결과 1개 업체의 것이 차단층의 두께가 다르고 열접착층 필름의 재질은 비슷한 것임을 알았고, 시험기로 찾은 최적 열접착조건은 $195^{\circ}C$와 $210^{\circ}C$로 $15^{\circ}C$의 차이를 보였으며 이를 종형 4면 액체충전포장기로 직접 충전 포장하였을 때의 봉지의 열접착 강도를 비교한 결과 최적 열접착 조건 $195^{\circ}C$의 것은 평균 $4.76kg/cm^2/15mm,\;210^{\circ}C$의 것은 평균 $3.84kg/cm^2/15mm$이었다.

• Journal of Plant Biology
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• 제37권3호
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• pp.309-316
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• 1994

To make regional comparisons of water status of pitch pine, the temporal changes of water status in pitch pine were investigated at different areas; urban Seoul (heavily polluted area), surburb of Seoul (lightly polluted area), and rural area (control). The effects of air pollutants, acid rain and chemical properties of soil on water deficit in pitch pine were also investiaged. Water content of needles growing at polluted areas were usually lower than that at unpolluted area. Water saturation deficit of needles growing at polluted areas were usually higher than that at unpolluted area especially in dry season. These results indicated that water in needles growing at polluted areas were usually more deficient than that at unpolluted area, and were more deficient in April than other months. At polluted areas, the older the needles were, the more quickly transpirated the water in the needle was. At unpolluted areas, however, water in old needles was not so quickly transpirated as those at polluted areas. Water potential of needles of pitch pine seedlings treated with simulated acid rain (SAR) of pH 3.5 decreased more quickly than that of needles treated with SAR of pH 5.6. Loss of water through epicuticular layer was greater in the following order: magnesium deficiency＋100 $\mu$M aluminium>100$\mu$M aluminium>magnesium deficiency>control. In addition to Mg deficiency and Al toxicity, growth decline of pitch pine widely occurring in polluated Seoul could to a large extent be due to cuticle degredation and abnormal vertical distribution of fine roots, which lead to water stress, particularly in dry seasons.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.245-248
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• 2011

Many researches have been carried out to improve light absorption in the crystalline silicon solar cell fabrication. The rear reflection is applied to increase the path length of light, resulting in the light absorption enhancement and thus the efficiency improvement mainly due to increase in short circuit current. In this paper, we manufactured the silicon solar cell using the mono crystalline silicon wafers with $156{\times}156mm^2$, 0.5~3.0 ${\Omega}{\cdot}cm$ of resistivity and p-type. After saw damage removal, the dielectric film ($SiN_x$)on the back surface was deposited, followed by surface texturing in the KOH solution. It resulted in single-side texturing wafer. Then the dielectric film was removed in the HF solution. The silicon wafers were doped with phosphorus by $POCl_3$ with the sheet resistance 50 ${\Omega}/{\Box}$ and then the silicon nitride was deposited on the front surface by the PECVD with 80nm thickness. The electrodes were formed by screen-printing with Ag and Al paste for front and back surface, respectively. The reflectance and transmittance for the single-sided and double-sided textured wafers were compared. The double-sided textured wafer showed higher reflectance and lower transmittance at the long wavelength region, compared to single-sided. The completed crystalline silicon solar cells with different back surface texture showed the conversion efficiency of 17.4% for the single sided and 17.3% for the double sided. The efficiency improvement with single-sided textured solar cell resulted from reflectance increase on back surface and light absorption enhancement.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.658-658
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• 2013

Graphene is an attractive material for various device applications due to great electrical properties and chemical properties. However, lack of band gap is significant hurdle of graphene for future electrical device applications. In the past few years, several methods have been attempted to open and tune a band gap of graphene. For example, researchers try to fabricate graphene nanoribbon (GNR) using various templates or unzip the carbon nanotubes itself. However, these methods generate small driving currents or transconductances because of the large amount of scattering source at edge of GNRs. At 2009, Bai et al. introduced graphene nanomesh (GNM) structures which can open the band gap of large area graphene at room temperature with high current. However, this method is complex and only small area is possible. For practical applications, it needs more simple and large scale process. Herein, we introduce a photosensitive graphene device fabrication using CdSe QD coated nano-porous graphene (NPG). In our experiment, NPG was fabricated by thin film anodic aluminum oxide (AAO) film as an etching mask. First of all, we transfer the AAO on the graphene. And then, we etch the graphene using O2 reactive ion etching (RIE). Finally, we fabricate graphene device thorough photolithography process. We can control the length of NPG neckwidth from AAO pore widening time and RIE etching time. And we can increase size of NPG as large as 2 $cm^2$. Thin CdSe QD layer was deposited by spin coatingprocess. We carried out NPG structure by using field emission scanning electron microscopy (FE-SEM). And device measurements were done by Keithley 4200 SCS with 532 nm laser beam (5 mW) irradiation.

• ETRI Journal
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• 제31권6호
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• pp.660-666
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• 2009

We investigate the effects of interfacial dielectric layers (IDLs) on the electrical properties of top-gate In-Ga-Zn-oxide (IGZO) thin film transistors (TFTs) fabricated at low temperatures below $200^{\circ}C$, using a target composition of In:Ga:Zn = 2:1:2 (atomic ratio). Using four types of TFT structures combined with such dielectric materials as $Si_3N_4$ and $Al_2O_3$, the electrical properties are analyzed. After post-annealing at $200^{\circ}C$ for 1 hour in an $O_2$ ambient, the sub-threshold swing is improved in all TFT types, which indicates a reduction of the interfacial trap sites. During negative-bias stress tests on TFTs with a $Si_3N_4$ IDL, the degradation sources are closely related to unstable bond states, such as Si-based broken bonds and hydrogen-based bonds. From constant-current stress tests of $I_d$ = 3 ${\mu}A$, an IGZO-TFT with heat-treated $Si_3N_4$ IDL shows a good stability performance, which is attributed to the compensation effect of the original charge-injection and electron-trapping behavior.

• JSTS:Journal of Semiconductor Technology and Science
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• 제4권2호
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• pp.117-123
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• 2004

A 30 nm $In_{0.7}GaAs$ High Electron Mobility Transistor (HEMT) with triple-gate has been successfully fabricated using the $SiO_2/SiN_x$ sidewall process and BCB planarization. The sidewall gate process was used to obtain finer lines, and the width of the initial line could be lessened to half by this process. To fill the Schottky metal effectively to a narrow gate line after applying the developed sidewall process, the sputtered tungsten (W) metal was utilized instead of conventional e-beam evaporated metal. To reduce the parasitic capacitance through dielectric layers and the gate metal resistance ($R_g$), the etchedback BCB with a low dielectric constant was used as the supporting layer of a wide gate head, which also offered extremely low Rg of 1.7 Ohm for a total gate width ($W_g$) of 2x100m. The fabricated 30nm $In_{0.7}GaAs$ HEMTs showed $V_{th}$of -0.4V, $G_{m,max}$ of 1.7S/mm, and $f_T$ of 421GHz. These results indicate that InGaAs nano-HEMT with excellent device performance could be successfully fabricated through a reproducible and damage-free sidewall process without the aid of state-of-the-art lithography equipment. We also believe that the developed process will be directly applicable to the fabrication of deep sub-50nm InGaAs HEMTs if the initial line length can be reduced to below 50nm order.

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3645-3650
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• 2012

Two new blue emitting cationic iridium(III) complexes with two substituted 2-phenlypyridine ligands as main ligands and one 2,2'-biimidazole as an ancillary ligand, $[(L1)_2Ir(biim)]Cl$ (1) and $[(L2)_2Ir(biim)]Cl$ (2), where L1 = 2-(2',4'-difluorophenyl)-4-methylpyridine, L2 = 2-(2',4'-difluoro-3'-trifluoromethylphenyl)-4-methylpyridine and biim = 2,2'-biimidazole, were synthesized for applications in phosphorescent organic light-emitting diodes (PhOLEDs). Their photophysical, electrochemical and electroluminescent (EL) device performances were examined. The photoluminescent (PL) spectra revealed blue phosphorescence in the 450 to 485 nm range with a quantum yield of more than 10%. The iridium(III) compounds studied showed good solubility in organic solvents with no solvatochromism dependent on the solvent polarity. The solution-processed OLEDs were prepared with the configuration, ITO/PEDOT:PSS (40 nm)/mCP:Ir(III) (70 nm)/OXD-7 (20 nm)/LiF (1 nm)/Al (100 nm), by spin coating the emitting layer containing the mCP host doped with the iridium phosphors. The best performance of the fabricated OLEDs based on compound 1 showed an external quantum efficiency of 4.5%, luminance efficiency of 8.52 cd $A^{-1}$ and blue emission with the CIE coordinates (x,y) of (0.16, 0.33).

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.1472-1477
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• 2009

매립지반이 주로 사질토로 구성되어 있거나 호박돌을 많이 함유하고 있는 지반이나 쓰레기 매립지반에서는 시공속도가 매우 빠르고 경제적 측면을 고려한 동다짐공법이 많이 적용되고 있다. 본 연구에서는 대구서부화물역 건설공사의 쓰레기 매립층에 적용된 동다짐공법에 대하여 지반개량효과를 분석하였다. 그 결과 중추낙하다짐 적용구간에 N치는 6.5/30에서 22.5/30으로 약 349% 증가하였다. 다짐전과 후의 지반고 측정결과 중추낙하다짐공법 적용구간은 0.706~1.729m가 침하되었다. 중추낙하다짐에 의한 $\alpha$값은 0.25~0.48로 폐기물층에 대한 일본토질공학회(1987)의 연구결과(0.3~0.5) 및 광산폐기물에 대한 Lukas(1986)의 연구결과(0.35~0.4)와 유사한 범위를 보이고 있다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.168-168
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• 2008

Dimension of a transistor has rapidly shrunk to increase the speed of device and to reduce the power consumption. However, it is accompanied with several problems like direct tunneling through the gate dioxide layer and low conductivity characteristic of poly-Si gate in nano-region. To cover these faults, study of new materials is urgently needed. Recently, high dielectric materials like $Al_2O_3$, $ZrO_2$, and $HfO_2$ are being studied for equivalent oxide thickness (EOT). However, poly-Si gate is not compatible with high-k materials for gate-insulator. Poly Si gate with high-k material has some problems such as gate depletion and dopant penetration problems. Therefore, new gate structure or materials that are compatible with high-k materials are also needed. TiN for metal/high-k gate stack is conductive enough to allow a good electrical connection and compatible with high-k materials. According to this trend, the study on dry etching of TiN for metal/high-k gate stack is needed. In this study, the investigations of the TiN etching characteristics were carried out using the inductively coupled $BCl_3$-based plasma system and adding $Cl_2$ gas. Dry etching of the TiN was studied by varying the etching parameters including $BCl_3$/Ar gas mixing ratio, RF power, DC-bias voltage to substrate, and $Cl_2$ gas addition. The plasmas were characterized by optical emission spectroscopy analysis. Scanning electron microscopy was used to investigate the etching profile.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.411-412
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• 2008

We have studied a property change of organic light-emitting diodes (OLED) due to an indium tin oxide (ITO) surface reformation. The characteristics of OLED were improved by oxygen plasma processing of an ITO in this work. ITO is widely used as a transparent electrode in light-emitting devices, and the OLED device performance is sensitive to the surface properties of the ITO. The OLED devices with the structure of ITO/TPD(50nm)/$Alq_3$(70nm)/LiF(0.5nm)/Al(100nm) were fabricated, and the surface properties of ITO were investigated by using various characterization techniques. The oxygen plasma process of an ITO was processed by using RF power of 125W and oxygen partial pressure of $2\times10^{-2}$ Torr. The oxygen plasma processing of an ITO processed for 0/1/2/3/4min. Current-voltage-luminance characteristics of the devices show that turn-on voltage is 4V for 2min device and the luminance reaches about 27,000cd/$m^2$ for 4min device. The current efficiency shows that 3min device becomes saturated to be about 8cd/ A. They show that emission was from the $Alq_3$ layer, because the peak wavelength is about 525nm. View angle-dependent emission spectra show that the emission intensity decreases as the angle increases.