• Transactions on Electrical and Electronic Materials
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• v.12 no.4
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• pp.164-168
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• 2011

Nanocrystalline cadmium sulphide (CdS) thin films were prepared using chemical bath deposition (CBD), and the structural, optical and photoconductive properties were investigated. The crystal structure of CdS thin film was studied by X-ray diffraction. The crystallite size, dislocation density and lattice constant of CBD CdS thin films were investigated. The dislocation density of CdS thin films initially decreases with increasing film thickness, and it is nearly constant over the thickness of 2,500 ${\AA}$. The dislocation density decreases with increasing the crystallite size. The Urbach energies of CdS thin films are obtained by fitting the optical absorption coefficient. The optical band gap of CdS thin films increases and finally saturates with increasing the lattice constant. The Urbach energy and optical band gap of the 2,900 A-thick CdS thin film prepared for 60 minutes are 0.24 eV and 2.83 eV, respectively. The activation energies of the 2,900 ${\AA}$-thick CdS thin film at low and high temperature regions were 14 meV and 31 meV, respectively. It is considered that these activation energies correspond to donor levels associated with shallow traps or surface states of CdS thin film. Also, the value of ${\gamma}$ was obtained from the light transfer characteristic of CdS thin film. The value of ${\gamma}$ for the 2,900 A-thick CdS thin film was 1 at 10 V, and it saturates with increasing the applied voltage.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.4
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• pp.646-651
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• 1987

The photoconductive multilayer composed of glassy, porous, and fine-grained layers was fabdricated with Se and Sb2S3 by vacuum evaporation in order to be used as vidicon target. And its electrical, optical properties were investigatee. The fabrication conditions were as follow: the glassy layer was first deposited to have the thickness of 6500 \ulcornerat the deposition rate of 250\ulcornersec. High photosensitivity(\ulcorner=1) was obtained but its shortcoming was high dielectric constant. Therefore, the porous layer was added to lower dielectric constant and had 7500\ulcornerthick in the argon gas ambikent of 7x10-\ulcorner And the fine-grained layer was formed to prevent secondary electron emission and obtain good resolution. Its thickness was about 1700\ulcorner For the given vidicon target, the light transfer characteristic, that is, photosensitivity (\ulcorner) was measured to be 0.8 at the applied voltage of 25V. The spectral sensitivity was quite similar to that of the human eyes.

• Journal of the Korean institute of surface engineering
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• v.37 no.3
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• pp.158-163
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• 2004

ITO thin film was deposited on the glass by RF magnetron sputtering. Dependance of the process parameters such as thickness, target-to-substrate distance, substrate temperature and oxygen partial pressure on the transmittance and electrical resistance of ITO film were investigated. The deposition conditions for getting better optical and electrical ITO characteristics were the 1800-$2300\AA$ thickness, 65mm substrate-to-target distance, $350^{\circ}C$ substrate temperature and 8% oxygen partial pressure. At these conditions, the transmittance and sheet resistance of the ITO film were 83.3% and 77.86Ω/$\square$, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.10
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• pp.2247-2252
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• 2012

In this paper, we produced CIGS thin film by co-evaporation method. During the process, substrate temperature and Ga/(In+Ga) composition ratio was altered to observe the change of resistivity and absorbance spectra measurements. As substrate temperature increased, resistivity decreased and as Ga/(In+Ga) composition ratio increased from 0.30 to 0.72, band gap also increased with the range of 1.26eV, 1.30eV, 1.43eV, 1.47eV. With the constant condition of composition ratio, resistivity decreased with increased thickness of the thin film. On this experiment, we assumed that optical absorbance ratio and optical current will be increased with CIGS thin film fabrication.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.9
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• pp.1782-1792
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• 1994

Ti : $LiNbO_3$ traveling-wave phase optical modulators at wavelength 1.3㎛ have been designed and fabricated, focusing on the optical waveguide and asymmetric coplanar electrode structure. To improve the phase-mismatch of traveling-wave ACPS electrode, the characteristic impedance, effective microwave index, and electrode loss have been presented as a function of geometric parameters including electrode and buffer layer thickness. Low-loss channel optical waveguides on $LiNbO_3$ were fabricated by the Ti diffusion method with $O_2$ water-vapor environment. $2.5{\mu}m$ thick electrode was successfully fabricated by double-spin image reversal process. Modulation bandwidth was limited by a resonance at 2.9 GHz and modulation bandwidth up to 2.5GHz was approxirnately measured.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.275-277
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• 1999

A application possibility of photoresist flexible film for optical waveguide is proposed and described. The optical waveguide dimensions that is consists of Mach-zehnder interferometric and single channel waveguide based on the single-mode conditions in LiNbO$_3$ device was utilized and fabricated by wet etching technique. This Polymer material for core layer is SU-8/5O(Microchem.) and its refractive index from prism couping method was measured about 1.59 thickness about 10${\mu}{\textrm}{m}$ at wavelength 0.6328${\mu}{\textrm}{m}$. From the results, this work can show the possibility of fabricating a flexible optical waveguide in the field of integrated optics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04a
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• pp.201-203
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• 2000

To improve characteristics of optical devices that used be WDM system optimally, we investigated characteristics of two types structures that consisted of non-uniform thickness Quantum well. They have high characteristic temperature and 3dB bandwidth of spontaneous emission are 57nm, 50nm respectively, which are 1.4times, 1.3times wider than conventional structure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.1
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• pp.83-88
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• 2004

BAlq was fabricated as for hole blocking layer in the OLED devices to investigate its electrical and optical characteristics. Device structure was ITO/$\alpha$ -NPD/EML/BAlq/Alq3/Al:Li using TYG-201, DPVBi (4, 4 - Bis (2, 2 - diphenylethen-1 - yls) - Biphenyl), Alq and DCJTB (4-(dicyanomethylene)-2- (1-propyls)6-methy 4H-pyrans) as green emitting material, blue emitting material, host material for red emission and red emitting guest material respectively. The OLED device showed optimum working voltage and electron density at 600 cd/$m^2$ when thickness of BAlq is 25$\AA$ for RGB OLED devices while their efficiencies are better at 50$\AA$ of BAlq. Red and blue color OLEDs also fabricated using 30$\AA$ thickness of BAlq and compared with those without BAlq layer. BAlq was more effective in electrical properties such as working voltage, current density and efficiency of red OLED than blue and green ones. This study describes that 30$\AA$ is optimum thickness of BAlq for best performance of full color OLED devices when using BAlq as a hole blocking material.

• Journal of agriculture & life science
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• v.51 no.6
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• pp.15-22
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• 2017

The microstructure observation of seed surface structure is needed for protocols of breaking dormancy of seeds with physical dormancy. The seeds of Rubus species are surrounded by a thick, hard endocarp; together, the seed and endocarp make up the stone. We evaluate stone characteristics of 18 species of Rubus through optical microscopic observation, and correlate different stone characteristics with endocarp thickness. As a result of stone size comparison, Rubus species were classified as big stones group including R. parvifolius and R. idaeus, small stones group including R. longisepalus var. longisepalus, R. corchorifolius and R. hirsutus, and middle stones group including rest of the species. The result of this study revealed that stone size and the endocarp thickness in Rubus species was various characteristics in each species. Furthermore stone size and stone weight were also well correlated endocarp thickness and result indicated that heavy stones had harder endocarp than lighter one. Thus from the result of this study it can be presumed that only one stone characteristic approach may be sufficient to estimate other characteristics in Rubus.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.4
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• pp.203-208
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• 2014

In this study, Sputtering method was used to grow Al-dopes ZnO films on a CIGS absorber layer, in order to examine the effect of TCO on properties of CIGS solar cell devices. Structural, electrical and optical properties were investigated by varied thickness of Al-dopes ZnO films. Also, relation to the application as a window layer in CIGS thin film solar cell were studied. It was found that the electrical and structural properties of ZnO:Al film improved with increasing its thickness. However, the optical properties degraded. Jsc of the fabricated CIGS based solar cells was significantly influenced by the variation of the ZnO:Al window layer thickness. Because ZnO:Al window layer is one of the Rs factors in CIGS solar cell. Rs has the biggest influence on efficiency characteristic. In order to obtain high efficiency of CIGS solar cell, ZnO:Al window layer should be fabricated with electrically and optically optimized.