• Bulletin of the Korean Chemical Society
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• 제32권11호
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• pp.4121-4124
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• 2011

• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1395-1398
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• 2011

• Bulletin of the Korean Chemical Society
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• 제34권8호
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• pp.2281-2285
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• 2013

The electronic structure, optical spectra, and thermodynamic properties of the three FOX-7 polymorphs (${\alpha}$, ${\beta}$, and ${\gamma}$) have been studied systematically using density functional theory. The LDA (CA-PZ) and generalized gradient approximation (GGA) (PW91) functions were used to relax the three FOX-7 phases without any constraint. Their density of states and partial density of states were calculated and analyzed. The band gaps for the three phases were calculated and the sequence of their sensitivity was presented. Their absorption coefficients were computed and compared. The thermodynamic functions including enthalpy (H), entropy (S), free energy (G), and heat capacity ($C_p$) for the three phases were evaluated.

• 반도체디스플레이기술학회지
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• 제15권1호
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• pp.70-75
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• 2016

GZO films prepared on ITO glasses were annealed at various temperatures in a vacuum condition to research the relationship between oxygen vacancies and optical properties. GZO films after annealing in a vacuum showed the various optical-chemical properties depending on the annealing temperatures and oxygen gas flow rate during the deposition. The oxygen vacancy of GZO film prepared by oxygen gas flows of 22 sccm increased with increasing the annealing temperatures, because of the extraction of oxygen by the annealing. But the intensity of photoluminance of GZO with 22 sccm decreased in accordance with the annealing temperature, because of the reduction of ionized charge carriers. The oxygen vacancy by the extraction of oxygen enhanced a depletion, so the widen depletion had the strong Schottky barrier and the PL intensity due to the low carrier density decreased.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.179-179
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• 2012

Low pressure radio-frequency glow discharges are investigated using theoretical modeling and various experimental diagnostic methods. In the calculations, global models and transformer models are developed to understand the chemical kinetics as well as the electrical properties such as the effective collision frequency, the heating mechanism and the power transferred to the plasma electrons. In addition, Boltzmann equation solver is used to compensate the effect of the electron energy distribution function (EEDF) shape in the global model, and the general expression of energy balance for non-Maxwellian electrons is developed. In the experiments, a number of traditional plasma diagnostic methods are used to compare with calculated results such as Langmuir probe, optical emission spectroscopy (OES), optical absorption spectroscopy (OAS) and two-photon absorption laser-induced fluorescence (TALIF). These theoretical and experimental methods are applied to understand several interesting phenomena in low pressure ICP discharges. The chemical and physical properties of low pressure ICP discharges are described and the applications of these methods are discussed.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.454-454
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• 2010

In order to achieve a high efficient a-Si solar cell, the TCO (transparent conductive oxide) substrates are required to be a low sheet resistivity, a high transparency, and a textured surface with light trapping effect. Recently, a zinc oxide (ZnO) thin film attracts our attention as new coating material having a good transparent and conductive for TCO of solar cells. In this paper the optical properties of $H_2$ post-treated BZO (boron doped ZnO, ZnO:B) thin film are investigated with $O_2$-plasma treatment. The BZO thin films by MOCVD (Metal Organic Chemical Vapor Deposition) are investigated and the samples of $H_2$ post-treated BZO thin film are tested with $O_2$-plasma treatment by plasma treatment system with 13.56 MHz as RIE (Reactive Ion Etching) type. We measured the optical properties and surface morphology of BZO thin film with and without $O_2$-plasma treatment. The optical properties such as transmittance, reflectance and haze are measured with integrating sphere and ellipsometer. This result of the BZO thin film with and without $O_2$-plasma treatment is application to the TCO for solar cells.

• Journal of Photoscience
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• 제3권3호
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• pp.159-161
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• 1996

Photosensitivity of silver halide emulsion depends on the properties of the microcrystals. Size, shape, grain distribution and chemical composition as well as the inner structure or the topography of the latent image specks affect on the optical properties and play an important role in the photographic process. In the present paper, a study on the sensitization of emulsion containing AgBrClI core/shell grains showed that for the given size, shape, halide content and crystal habit, under the optimal conditions the photosensitivity of the heterojunction type grains are different from that of the common regular grains. The optimal photosensitivity was obtained at the iodide content of 2.0 mo1%.

• Bulletin of the Korean Chemical Society
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• 제12권5호
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• pp.477-483
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• 1991

In the three-parameter ellipsometry (TPE), also known as reflectance-ellipsometry, the ellipsometric measurements, ${\Psi} and {\Delta}$, are combined with the reflectometric measurement, R, to determine the optical parameters and the thickness of a light-absorbing thin film. The constant ${\Psi}, {\Delta}$ and R surfaces are analyzed graphically to understand the nature of the TPE solutions. A sensitivityanalysis is shown to be useful not only for identifying the film properties which affect most the TPE measurements, but also for estimating errors in film properties arising from the uncertainties in measurements.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.298.1-298.1
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• 2016

Two-dimensional materials have been received significant interest after the discovery of graphene due to their fascinating electronic and optical properties for the application of novel devices. However, graphene lack of certain bandgap which is essential requirement to achieve high performance field-effect transistors. Analogous to graphene materials, molybdenum disulfide ($MoS_2$) as one of transition-metal dichalcogenides family presents considerable bandgap and exhibits promising physical, chemical, optical and mechanical properties. Here we studied nonvolatile memory based on $MoS_2$ which is grown by chemical vapor deposition (CVD) method. $MoS_2$ growth was taken on $1.5{\times}1.5cm^2$ $SiO_2$/Si-substrate. The samples were analyzed by Raman spectroscopy, atomic force microscopy and X-ray photoelectron spectroscopy. Current-voltage (I-V) characteristic was carried out HP4156A. The CVD-$MoS_2$ was analyzed as few layers and 2H-$MoS_2$ structure. From I-V measurement for two metal contacts on CVD-$MoS_2$ sample, we found typical resistive switching memory effect. The device structures and the origin of nonvolatile memory effect will be discussed.

• 한국전기전자재료학회논문지
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• 제16권4호
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• pp.272-279
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• 2003

In this work Zn$_4$GeSe$_{6}$ :CO$^{2+}$ single crystals were grown by the chemical transport reaction method in which the iodine was used as the transporting agent. The Zn$_4$GeSe$_{6}$ :CO$^{2+}$ single crystal was found to have a monoclinic structure. The optical absorption spectra of grown crystals were investigated using a temperature-controlled UV-VIS -NIR spectrophotometer. The temperature dependence of band-edge absorption was in a good agreement with the Varshni equation. The observed impurity absorption peaks could be explained as arising from the electron transition between energy levels of Co$^{2+}$ ion sited at the T$_{d}$ symmetry point.