• Korean Journal of Materials Research
• /
• v.26 no.4
• /
• pp.222-227
• /
• 2016

Tin oxides have been studied for various applications such as gas detecting materials, transparent electrodes, transparent devices, and solar cells. p-type SnO is a promising transparent oxide semiconductor because of its high optical transparency and excellent electrical properties. In this study, we fabricated p-type SnO thin film using rf magnetron sputtering with an SnO/Sn composite target; we examined the effects of various oxygen flow rates on the SnO thin films. We fundamentally investigated the structural, optical, and electrical properties of the p-type SnO thin films utilizing X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV/Vis spectrometry, and Hall Effect measurement. A p-type SnO thin film of $P_{O2}=3%$ was obtained with > 80% transmittance, carrier concentration of $1.12{\times}10^{18}cm^{-3}$, and mobility of $1.18cm^2V^{-1}s^{-1}$. With increasing of the oxygen partial pressure, electrical conductivity transition from p-type to n-type was observed in the SnO crystal structure.

• 한국신재생에너지학회:학술대회논문집
• /
• 2011.05a
• /
• pp.121.2-121.2
• /
• 2011

Aluminum-doped Zinc Oxide (AZO) is considered as an excellent candidate to replace Indium Tin Oxide (ITO), which is widely used as transparent conductive oxide (TCO) for electronic devices such as liquid crystal displays (LCDs), organic light emitting diodes (OLEDs) and organic solar cells (OSCs). In the present study, AZO thin film was applied to the transparent electrode of a channel-shaped flexible organic solar cell using a low-temperature selective-area atomic layer deposition (ALD) process. AZO thin films were deposited on Poly-Ethylene-Naphthalate (PEN) substrates with Di-Ethyl-Zinc (DEZ) and Tri-Methyl-Aluminum (TMA) as precursors and $H_2O$ as an oxidant for the atomic layer deposition at the deposition temperature of $130^{\circ}C$. The pulse time of TMA, DEZ and $H_2O$, and purge time were 0.1 second and 20 second, respectively. The electrical and optical properties of the AZO films were characterized as a function of film thickness. The 300 nm-thick AZO film grown on a PEN substrate exhibited sheet resistance of $87{\Omega}$/square and optical transmittance of 84.3% at a wavelength between 400 and 800 nm.

• Journal of Powder Materials
• /
• v.15 no.3
• /
• pp.210-213
• /
• 2008

Elongated CdSe nanoparticles with a diameter of 3-7nm have been successfully synthesized using two surfactants of trioctylphospine (TOP) and hexadecylamine (HDA) at $160^{\circ}C$. The formation of elongated CdSe nanoparticles is possibly due to the cooperative effects from both the different binding capability of two surfactants (TOP and HDA) and intrinsically anisotropic crystal structure of the CdSe. The electron diffraction pattern of CdSe nanoparticles revealed the formation of wurzite phase. The CdSe samples showed red-shifted wavelength from 560 to 580nm with increasing the refluxing time due to the gradual growth of CdSe nanoparticles. The relatively broad absorption band can be attributed to the surface state of CdSe nanoparticles. The possible formation mechanism of elongated CdSe nanoparticles was proposed and the characteristics of CdSe have been discussed as well.

• Microbiology and Biotechnology Letters
• /
• v.18 no.6
• /
• pp.647-652
• /
• 1990

The production of delta-endotoxin crystal and the cloning of endotoxin protein gene in Bscillus thuringiensis subsp. kurstaki HD1 strain were studied. The strain produced bipyramidal crystals ($2.9\times 1.0 \mu m$) in their cells during sporulation. The B. thuringiensis contained about 10 plasmid DNA elements ranging from 2.1 to 80 kilobases. The 73 kb plasmid DNA, the 29 kb BamHI fragment and the 7.9 kb Pstl DNA fragment hybridized to the pHL probe. The 7.9 kb fragment was eluted and cloned in the PstI site of pBR322 vector and transformed into E. coli HB101, which produced insecticidal proteins killing Bornbyx mori larvae.

• Microbiology and Biotechnology Letters
• /
• v.23 no.2
• /
• pp.156-163
• /
• 1995

Bacillus sphaericus 1593 is pathogenic to the larvae of a number of mosquito species that are known as important vectors for the transmission of certain human and animal diseases. As a preliminary experiment for developing a multfunctional B. sphaericus 1593 as a potent antagonist, we investigated the conditions for the protoplast transformation system of B. sphaericus 1593 using the plasmid pGB215-110$\Delta$B. The protoplast of B. sphaericus 1593 were obtained most efficiency by treating the cells with 500 $\mu$g/ml of lysozyme in the SMM buffer containing 0.5 M sucrose at pH 8.0 and 40$\circ$C for 60 minutes. The cell wall was regenerated on the plate containing 1.2% agar and 0.8 M mannitol. Under the best condition for protoplast formation and regeneration established in the work the highest frequency of transformation was achieved with the 40% PEG (M.W 4,000) treatment for 15 minutes of incubation at 4$\circ$C, and subsequently for 120 minutes incubation at 30$\circ$C for phenotypic expression. The highest transformation efficiency were observed at 1.0 $\mu$g/ml of the final concentration of the plasmid DNA and the plasmids were found to be fairly stable since about 70% of the plasmids were maintained after 8 successive daily transfers onto the fresh medium.

• The Korean Journal of Ceramics
• /
• v.2 no.1
• /
• pp.1-10
• /
• 1996

Transparent conducting $SnO_2$-based thin films have been coated on float substrates such as fused quartz, and ceramic fiber cloths such as the Nexel and E-glass cloth from tin alkoxides by the sol-gel technique. Also, thin films of alternating layers of $SnO_2$ and $SiO_2$ have been fabricated by dip coating. The sheet resistance and average visible transmittance of the films were investigated in the aspect of the applications as transparent electrodes such as liquid crystal displays, photo-detectors and solar cells. The Nextel and E-glass cloths coated with antimony-doped tin oxide (ATO) had sheet resistance of as low as $20 \;ohm/{\Box}$ and $120ohm/\;{\Box}$, respectively. The promotion effects of additives as $La_2O_3$ and Pt on the ethanol gas sensing properties of the films were investigated in the aspects of the applications as an alcohol sensor and a breath alcohol checker. Possible evidence of quantum well effects in the oxide multilayers of $SnO_2$ and $SiO_2$ was investigated.

• Proceedings of the KIEE Conference
• /
• 1998.07d
• /
• pp.1391-1394
• /
• 1998

In this paper, we investigated the generation of pretilt for nematic liquid crystal (NLC) in a cell with linearly polarized ultraviolet (UV) light irradiation on polyimide (PI) surface. The pretilt angle of the NLC increases with increasing the incident angle in the cells with S-wave polarized UV light irradiation on PI surface. It is considered that the pretilt angle of the NLC increased due to decreasing the UV light intencity. We suggest that the pretilt angle of the NLC is attributed to asymmetry triangular of the polymer surface with S-wave polarized UV light irradiation on PI surface. Also, we consider that the asymmetry triangular of the Polymer not formed with P-wave polarized UV light irradiation on PI surface. Therefore, the pretilt angle of the NLC is attributed to asymmetry triangular of the polymer surface with UV light irradiation on PI surface.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.8
• /
• pp.2317-2325
• /
• 2014

P-glycoprotein (P-gp) is a member of the ATP-Binding Cassette transporter superfamily and mediates transmembrane efflux of many drugs. Since it is involved in multi-drug resistance activity in various cancer cells, the development of P-gp inhibitor is one of the major concerns in anticancer therapy. Human P-gp protein has at least two "functional" drug binding sites that are called "H" site and "R" site, hence it has multi-binding-specificities. Though the amino acid residues that constitute in drug binding pockets have been proposed by previous experimental evidences, the shapes and the binding poses are not revealed clearly yet. In this study, human P-gp structure was built by homology modeling with available crystal structure of mouse P-gp as a template and docking simulations were performed with inhibitors such as verapamil, hoechst33342, and rhodamine123 to construct the interaction between human P-gp and its inhibitors. The docking simulations were performed 500 times for each inhibitor, and then the interaction frequency of the amino acids at the binding poses was analyzed. With the analysis results, we proposed highly contributing residues that constitute binding pockets of the human P-gp for the inhibitors. Using the highly contributing residues, we proposed the locations and the shapes of verapamil binding site and "R" site, and suggested the possible position of "H" site.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.04b
• /
• pp.51-55
• /
• 2004

$CdS_{0.69}Se_{0.31}$ single crystal grown by sublimation method. Hall effect measurement were carried out by the Van der Pauw method. The measurement values under the temperature were found to be carrier density $n=1.95{\times}10^{23}m^{-3}$, Hall coeffcient $RH=3.21{\times}10^{-5}m^3/c$, conductivity ${\sigma}=362.41{\Omega}^{-1}m^{-1}$, and Hall mobility ${\mu}=1.16{\times}10^{-2}m^2/v.s.$ Heterojunction solar cells of $n-CdS_{0.69}Se_{0.31}/p-Cu_{2-x}S_{0.69}Se_{0.31}$ were fabricated by the substitution reaction. The open-circuit voltage, short-circuit currint density, fill factor and power conversion efficiency of $n-CdS_{0.69}Se_{0.31}/p-Cu_{2-x}S_{0.69}Se_{0.31}$ heterojunction solar cell under $80mW/cm^2$ illumination were found to be 0.41V, $19.5mA/cm^2$, 0.75 and 9.99%, respectivity.

• Journal of the Korean institute of surface engineering
• /
• v.29 no.6
• /
• pp.666-672
• /
• 1996

The optical property of CdTe thin film is important for applications such as the compound semiconductor type solar cells. CdTe films are prepared by RF sputtering at various substrate temperature between $25^{\circ}C$ and $300^{\circ}C$, then, annealed in argon gas environment at $400^{\circ}C$. The annealing process of the thin film caused variation in the film structure and the composition of films. The deformation of CdTe thin film was observed by X-ray diffractometry. After annealing, the grain size increased and the portion of the non-crystalline CdTe reduced. Futhermore, the structure of sputtered CdTe film grown at the substrate temperature more than $250^{\circ}C$ was enhanced in the (111) direction of zincblend structure. There was a discrepancy, in the spectroscopic ellipsometer spectrum, between the single crystal CdTe and the sputtered CdTe thin films, especially in the region over 3.2eV. An oxidation layer was found on the CdTe thin film by spectroscopic ellipsometry analysis.