• Korean Journal of Clinical Laboratory Science
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• v.46 no.3
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• pp.99-105
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• 2014

Isolating total DNA from small samples using traditional methods is difficult and inefficient mainly due to loss of DNA during filtration and precipitation. With advances in molecular pathology, DNA extraction from micro-dissected cells has become essential in handling clinical samples. Genomic DNA extraction using small numbers of cells can be very important to successfully PCR amplify DNA from small biopsy specimens. We compared our experimental genomic DNA extraction method (A) with two other commercially available methods: using spin columns (B), and conventional resins (C), and determined the efficacy of DNA extraction from small numbers of cells smeared on a glass slide. Approximately 50, 100, 200, 500 and 1000 cells were isolated from fine needle aspiration biopsy (FNAB) slides aspirated from histologically proven papillary thyroid carcinoma masses. DNA was extracted using the three techniques. After measuring DNA quantity, PCR amplification was performed to detect the ${\beta}$-globin and $BRAF^{V600E}$ gene mutations. DNA extracted by method (A) showed better yield than the other methods in all cell groups. With our method, a suitable amount of genomic DNA to produce amplification was extracted from as few as 50 cells, while more than 100 to 200 cells were required when methods (B) or (C) were applied. Our genomic DNA extraction method provides high quality and improved yields for molecular analysis. It will be especially useful for paucicellular clinical samples which molecular pathologists often confront when handling fine needle aspiration cytology, exfoliative cytology and small biopsy specimens.

• Journal of IKEEE
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• v.23 no.2
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• pp.594-598
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• 2019

We demonstrate an alternative alignment process using transferring process on solution driven HfZnO film. Parallel pattern is firstly fabricated on a silicon wafer by laser interference lithography. Prepared HfZnO solution fabricated by sol-gel process is spin-coated on a glass substrate. The silicon wafer with parallel pattern is placed on the HfZnO film and annealed at $100^{\circ}C$ for 30 min. After transferring process, parallel grooves on the HfZnO film is obtained which is confirmed by atomic force microscopy and scanning electron microscopy. Uniform liquid crystal alignment is achieved which is attributed to an anisotropic characteristic of HfZnO film by parallel grooves. The liquid crystal cell exhibited a pretilt angle of $0.25^{\circ}$ which showed a homogeneous alignment property.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.4
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• pp.256-261
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• 2021

Indium-doped Mg_0.05Zn_0.95O thin films were deposited on glass substrates by a sol-gel method. Three types of indium precursors such as indium chloride, indium acetate, and indium nitrate were used as doping sources. Physical properties of fabricated thin films were analyzed through XRD (x-ray diffraction), UV-vis spectrophotometer, Hall effect measurement, and EDS (energy dispersive x-ray spectroscopy). All In-doped thin films grown in this study exhibited a preferred orientation of (002) with over 80% transmittance. The results showed that the Mg_0.05Zn_0.95O thin film from indium chloride as the indium precursor has higher crystallinity and transmittance with lower resistivity when compared with those from other indium precursors.

• Journal of IKEEE
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• v.25 no.1
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• pp.64-68
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• 2021

We demonstrate an effect of annealing temperature on imprinting process of BiLaO thin film for liquid crystal alignment. BiLaO prepared sol-gel process was deposited by spin coating on a glass substrate, and then transferred to a pre-fabricated aligned pattern which is fabricated on a silicon wafer by laser interference lithography. Thin film was annealed at different temperature of 100, 150, 200, and 250 ℃. From the polarized optical microscopy analysis, the liquid crystal orientation was not uniform at the annealing temperature of 200 ℃ or lower and the uniform liquid crystal alignment characteristics were confirmed at the annealing temperature of 250 ℃. From atomic force microscopy, the pattern was not transferred at a temperature of 200 ℃ or lower. In contrast, the pattern was transferred at 250 ℃. Anisotropy of the thin film was obtained by the alignment pattern transferred at a temperature of 250 ℃, and the liquid crystal molecules could be evenly oriented on the thin film. Therefore, it was confirmed that the liquid crystal alignment process by the imprinting process of the BiLaO oxide film was affected by the annealing temperature.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.189-189
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• 2012

Lead sulfide (PbS) nanocrystal quantum dots (NQDs) are promising materials for various optoelectronic devices, especially solar cells, because of their tunability of the optical band-gap controlled by adjusting the diameter of NQDs. PbS is a IV-VI semiconductor enabling infrared-absorption and it can be synthesized using solution process methods. A wide choice of the diameter of PbS NQDs is also a benefit to achieve the quantum confinement regime due to its large Bohr exciton radius (20 nm). To exploit these desirable properties, many research groups have intensively studied to apply for the photovoltaic devices. There are several essential requirements to fabricate the efficient NQDs-based solar cell. First of all, highly confined PbS QDs should be synthesized resulting in a narrow peak with a small full width-half maximum value at the first exciton transition observed in UV-Vis absorbance and photoluminescence spectra. In other words, the size-uniformity of NQDs ought to secure under 5%. Second, PbS NQDs should be assembled carefully in order to enhance the electronic coupling between adjacent NQDs by controlling the inter-QDs distance. Finally, appropriate structure for the photovoltaic device is the key issue to extract the photo-generated carriers from light-absorbing layer in solar cell. In this step, workfunction and Fermi energy difference could be precisely considered for Schottky and hetero junction device, respectively. In this presentation, we introduce the strategy to obtain high performance solar cell fabricated using PbS NQDs below the size of the Bohr radius. The PbS NQDs with various diameters were synthesized using methods established by Hines with a few modifications. PbS NQDs solids were assembled using layer-by-layer spin-coating method. Subsequent ligand-exchange was carried out using 1,2-ethanedithiol (EDT) to reduce inter-NQDs distance. Finally, Schottky junction solar cells were fabricated on ITO-coated glass and 150 nm-thick Al was deposited on the top of PbS NQDs solids as a top electrode using thermal evaporation technique. To evaluate the solar cell performance, current-voltage (I-V) measurement were performed under AM 1.5G solar spectrum at 1 sun intensity. As a result, we could achieve the power conversion efficiency of 3.33% at Schottky junction solar cell. This result indicates that high performance solar cell is successfully fabricated by optimizing the all steps as mentioned above in this work.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.3
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• pp.193-203
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• 2005

Highly c-axis oriented nanocrystalline ZnO thin films on silica glass substrates were prepared by spin coating-pyrolysis process with a zinc naphthenate precursor. Only the XRD intensity peak of (002) phase was observed for all samples. With an increase in heat treatment temperature, the peak intensity of (002) phase increases. No significant aggregation of particle was present. From scanning probe microscopy analyses, three-dimensional grain growth, which was thought to be due to inhomogeneous substrate surface and c-axis oriented grain growth of the ZnO phase, was independent on heal-treatment temperature. Highly homogeneous surface of the highly-oriented ZnO film was observed at $800^{\circ}C$. All the films exhibited a high transmittance (above 80%) in visible region except film heat treated at $1000^{\circ}C$, and showed a sharp fundamental absorption edge at about $0.38{\sim}0.40{\mu}m$. The estimated energy band gap for all the films were within the range previously reported for films and single crystal. ZnO films, consisting of densely packed grains with smooth surface morphology were obtained by heat treatment at $600^{\circ}C{\sim}800^{\circ}C$, expected to be ideal for practical application, such as transparent conductive film and optical device.

• Polymer(Korea)
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• v.33 no.5
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• pp.407-412
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• 2009

Vacuum deposited N,N-di-1-naphthyl-N,N-diphenyl-1,1'-biphenyl-4,4'-diamine (NPD) as a hole transporting (HTL) materials in OLEDs was placed on PEDOT-PSS, a hole injection layer (HIL). PEDOT-PSS was spin-coated on to the ITO glass. $C_{60}$-doped NPD-$C_{60}$(10 wt%) film was formed via co-evaporation process and the morphology of NPD-$C_{60}$ films was investigated using XRD and AFM. The J - V, L - V and current efficiency of multi -layered devices were characterized. According to XRD results, the deposited $C_{60}$ thin film was partially crystalline, but NPD-$C_{60}$ film was observed not to be crystalline, which indicates that $C_{60}$ molecules are uniformly dispersed in the NPD film. By using $C_{60}$-doped NPD-$C_{60}$ film as a HTL, the current density and luminance of multi-layered ITO/PEDOT-PSS/NPD-$C_{60}/Alq_3$/LiF/Al device were significantly increased by about 80% and its efficiency was improved by about 25% in this study.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.4
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• pp.158-163
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• 2011

$CuInS_2$ thin films were prepared using a sol-gel spin-coating method. That makes large scale substrate coating, simple equipment, easy composition control available. The structural and optical properties of $CuInS_2$ thin films that include less toxic materials (S) instead of Se, tetragonal chalcopyrite structure. Copper acetate monohydrate ($Cu(CH_3COO)_2{\cdot}H2O$) and indium acetate ($In(CH_3COO)_3$) were dissolved into 2-propanol and l-propanol, respectively. The two solutions were mixed into a starting solution. The solution was dropped onto glass substrate, rotated at 3000 rpm, and dried at $300^{\circ}C$ for Cu-In as-grown films. The as-grown films were sulfurized inside a graphite container box and chalcopyrite phase of $CuInS_2$ was observed. To determine the optical properties measured optical transmittance of visible light region (380~770 nm) were less than 30 % in the overall. The XRD pattern shows that main peak was observed at Cu/In ratio 1.0 and its orientation was (112). As annealing temperature increases, the intensity of (112) plane increases. The unit cell constant are a = 5.5032 and c = 11.1064 $\AA$, and this was well matched with JCPDS card. The optical transmittance of visible region was below than 30 %.

• Journal of the Korean Magnetics Society
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• v.18 no.5
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• pp.180-184
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• 2008

The relation of ferromagnet anisotropic magnetization and the antiferromagnet atomic spin configuration has been investigated for variously angles of unidirectional deposition magnetic field of FeMn layer in Corning glas/Ta(5 nm)/NiFe(7 nm)/FeMn(25 nm)/ Ta(5 nm) multilayer prepared by ion beam deposition. Three unidirectional deposition angles of FeMn layer are $0^{\circ},\;45^{\circ}$, and $90^{\circ}$, respectively. The exchange bias field ($H_{ex}$) obtained from the measuring easy axis MR loop was decreased to 40 Oe in deposition angle of $45^{\circ}$, and to 0 Oe in the angle of $90^{\circ}$. One other side hand, $H_{ex}$ obtained from the measuring hard axis MR loop was increased to 35 Oe in deposition angle of $45^{\circ}$, and to 79 Oe in the angle of $90^{\circ}$. Although the difference of uniderectional axis between ferromagnet NiFe and antiferromagnet FeMn was 90o, the strong antiferromagnetic dipole moment of FeMn caused to rotate the weak ferromagnetic dipole moment of NiFe in the interface. This result implies that one of origins for exchange coupling mechanism depends on the effect of magnetic field angle during deposition of antiferromgnet FeMn layer.

• Journal of the Microelectronics and Packaging Society
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• v.20 no.2
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• pp.39-46
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• 2013

In this paper, organic solar cells(OSCs) based on bulk-heterojunction structures were fabricated by spin coating method using polymer P3HT and fullerene PCBM as a photoactive layer. The fabricated OSCs had a simple glass/ITO/PEDOT:PSS/P3HT:PCBM/Al structures. The photoactive layer of mixed P3HT:PCBM was formed with 1:1 weight ratio. The hole transport layer(HTL) was used conducting polymer PEDOT:PSS concentration with gold nanoparticles. The annealing temperature and concentration of nanoparticles in HTL were verified to improve the OSC characterization. The percentage of gold nanoparticles in HTL were 0.5 wt% and 1.0 wt%, and the surface morphology, electrical properties and absorption intensities were investigated. The devices were 0.5 wt%, and the highest 3.1% of the powder conversion efficiency(PCE), 10.2 $mA/cm^2$ of the maximum short circuit current density($J_{SC}$), 0.535V of the open circuit voltage($V_{OC}$) and 55.8% of the fill factor(F.F) could be obtained when the nanoparticle concertration was 0.5 wt%. The annealing temperature of HTL was $110^{\circ}C$, $130^{\circ}C$, $150^{\circ}C$ in vacuum oven and measured the absorption intensities, surface morphology, crystallinity and electrical properties were investigated. The best property was obtained in HTL annealed at $130^{\circ}C$ for gold nanoparticles of 0.5 wt%, showing that $J_{SC}$, $V_{OC}$, F.F and PCE were about 12.0 $mA/cm^2$, 0.525V, 64.2% and 4.0%, respectively.