• Journal of the Korean institute of surface engineering
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• v.49 no.5
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• pp.454-460
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• 2016

Double-layered Al-Mg films have been deposited by using an e-beam deposition method on a cold-rolled steel sheet(CR), which the structure of the film was Al/Mg/CR. The micro-structure, alloy phase, and corrosion resistance of the Al-Mg coated CR were investigated before and after heat treatment at $400^{\circ}C$ for 2, 3, and 10 min in a nitrogen atmosphere. Total thickness of Al-Mg films was fixed at $3{\mu}m$ and the thickness ratio of Al and Mg layers(Al:Mg) has been changed from 5:1 to 1:5. The cross-sectional morphology of the films, which had the thickness ratio of 2:1(Al:Mg), 1:1, and 1:2, was changed after heat treatment from columnar to featureless structure. The x-ray diffraction data for as-deposited films showed only pure Al and Mg peaks. Al-Mg alloy peaks such as $Al_3Mg_2$ and $Al_{12}Mg_{17}$ phase appeared after the heat treatment. The Al-Mg coating with the thickness ratio of 1:1(Al:Mg) showed the best corrosion resistance of up to 500 hours by salt spray test.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.966-969
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• 2003

Thin film capacitors with Al-Polymer-Al sandwich structure were fabricated. The bottom and top aluminium (Al) electrodes were deposited by vacuum evaporation and copper phthalocyanine (CuPc), polyaniline-emeraldine base (Pani-EB) and cobalt phthalocyanine/polyaniline - emeraldine base (CoPc /Pani-EB) blend films (which can be used as buffer hole injection layer in OLEDs) were deposited by spin coating technique. X-ray diffractograms indicated amorphous nature of the polymer films whose thicknesses were measured by capacitance and Rutherford Backscattering Spectrometry (RBS) methods. AC conduction studies revealed that the conduction mechanism responsible in these films is variable range hopping of polarons. From D.C conduction studies, it is observed that, the nature of conduction is ohmic in the lower fields and at higher fields the dominating D.C conduction is of Poole-Frenkel type.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.2
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• pp.54-57
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• 2005

Photoreflectance (PR) has been measured to investigate the characterization of the Si$_{3}$N$_{4}$Al$_{0.21}$ Ga$_{0.79}$As/GaAs and Al$_{0.21}$Ga$_{0.79}$As/GaAs heterostructures. In the PR spectrum, the caplayer thickness was 170 nm and Si$_{3}$N$_{4}$ was utilized as the capping material. The C peak is confirmed as the carbon defect with residual impurity originating from the growth process. After annealing, in the presence of the Si$_{2}$N$_{4}$ cap layer, band gap energy was low shifted. This result indicates that the Si$_{3}$N$_{4}$ cap layer controlled evaporation of the As atom.

• JSTS:Journal of Semiconductor Technology and Science
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• v.8 no.1
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• pp.40-45
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• 2008

We developed small molecular organic nonvolatile $4F^2$ memory cells using metal layer evaporation followed by $O_2$ plasma oxidation. Our memory cells sandwich an upper ${\alpha}$-NPD layer, Al nanocrystals surrounded by $Al_2O_3$, and a bottom ${\alpha}$-NPD layer between top and bottom electrodes. Their nonvolatile memory characteristics are excellent: the $V_{th},\;V_p$ (program), $V_e$ (erase), memory margin ($I_{on}/I_{off}$), data retention time, and erase and program endurance were 2.6 V, 5.3 V, 8.5 V, ${\approx}1.5{\times}10^2,\;1{\times}10^5s$, and $1{\times}10^3$ cycles, respectively. They also demonstrated symmetrical current versus voltage characteristics and a reversible erase and program process, indicating potential for terabit-level nonvolatile memory.

• Journal of the Korean Applied Science and Technology
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• v.14 no.2
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• pp.81-85
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• 1997

Tris(8-hydroxyquinoline)-aluminum complex($AlQ_3$) having greenish luminescent characteristics was synthesized and it was confirmed with UV-Vis absorption spectroscopy, elemental analysis, and FT-IR spectroscopy that $AlQ_3$ was successfully synthesized. Thin films of $AlQ_3$ having multilayer structure were prepared by spin coating method and vacuum evaporation technique. Photopluminescent characteristics of these films were investigated by Luminescence spectroscopy and Current-Voltage(I-V) characteristics of these films were also investigated.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.5
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• pp.214-216
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• 2005

Photoreflectance (PR) has been measured to investigate the characterization of the $Al_{0.20}Ga_{0.80}As$/GaAs heterostructures. In the PR spectrum, the 'C' peak is confirmed as the carbon defect with residual impurity originating from the growth process. After annealing, binding energy is relatively weak with As evaporation being done to increase Ga. Also obtained is the electric field value according to annealing temperature ($300{\sim}800^{\circ}C$).

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1568-1570
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• 2003

We have studied the I-V characteristics of polytetrafluoroethylene(PTFE) thin film depending on a variation of thickness. Polymer PTFE buffer layer was made using thermal evaporation technique. The device was made in the structure of ITO/PTFE/Al. We have observed the NDR(negative differential resistance) behavior between 2.5V and 5V. There are some reports on this NDR behavior in the polymer thin film[1]. We have studied the NDR behavior depending on a variation thickness. As the film thickness increased, The NDR behavior decreased and moved in low electrical field, and we have studied the conduction mechanism of PTFE thin film.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.05a
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• pp.119-120
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• 2015

SUS316L의 내부식성을 증진시키기 위해 우수한 내부식성 합금원소로 알려진 Al, Cr을 SUS316L에 Sputtering, E-beam evaporation하여 Al, Cr 코팅층을 형성시킨 후 대기 중, $Ar-1%SO_2$ 분위기에서 부식시켰다. 그 결과 코팅층에 의해 $600^{\circ}C$까지 $Al_2O_3$, $Cr_2O_3$ 형성되어 보호피막 역할을 함으로써 내부식성이 증진되었다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.11
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• pp.968-972
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• 2008

Ni/Ti/Al multilayer system ('/'denotes the deposition sequence) was tested for low-resistance ohmic contact formation to Al-implanted p-type 4H-SiC. Ni 30 nm / Ti 50 nm / Al 300 nm layers were sequentially deposited by e-beam evaporation on the 4H-SiC samples which were implanted with Al (norminal doping concentration = $4\times10^{19}cm^{-3}$) and then annealed at $1700^{\circ}C$ for dopant activation. Rapid thermal anneal (RTA) temperature for ohmic contact formation was varied in the range of $840\sim930^{\circ}C$. Specific contact resistances were extracted from the measured current vs. voltage (I-V) data of linear- and circular transfer length method (TLM) patterns. In constrast to Ni contact, Ni/Ti/Al contact shows perfectly linear I-V characteristics, and possesses much lower contact resistance of about $2\sim3\times10^{-4}\Omega{\cdot}cm^2$ even after low-temperature RTA at $840^{\circ}C$, which is about 2 orders of magnitude smaller than that of Ni contact. Therefore, it was shown that RTA temperature for ohmic contact formation can be lowered to at least $840^{\circ}C$ without significant compromise of contact resistance. X-ray diffraction (XRD) analysis indicated the existence of intermetallic compounds of Ni and Al as well as $NiSi_{1-x}$, but characteristic peaks of $Ti_{3}SiC_2$, a probable narrow-gap interfacial alloy responsible for low-resistance Ti/Al ohmic contact formation, were not detected. Therefore, Al in-diffusion into SiC surface region is considered to be the dominant mechanism of improvement in conduction behavior of Ni/Ti/Al contact.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.448-455
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• 2005

In this paper, an analytical model for estimation of the time at which the concrete surface begins to dry is introduced to predict whether or not plastic shrinkage cracks occur. First of all, the validity of a consolidation model for bleeding of cement paste proposed by Tan et al. is verified by comparing the analytical results with the experimental results, and used to evaluate the rate and amount of bleed water of concrete. Also an analytical model for evaporation of bleed water which considers the effect of the temperature variation of concrete surface due to hydration heat on the evaporation rate is proposed, and the experimental and analytical results are then compared to verify the validity of the introduced model. In advance, the time at which the concrete surface begins to dry is estimated using above two analytical models, and compared with the experimental results about the time at which plastic shrinkage cracks occur. From the comparison, it is verified that the proposed model can predict the occurrence of plastic shrinkage cracking with comparative precision.