• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.9
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• pp.808-811
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• 2008

Optical and mechanical properties of diamond-like carbon (DLC) films synthesized by RF plasma enhanced chemical vapor deposition were investigated as a function the C/H ratio in gas mixture. The C/H ratio was varied from 6 to 10 %, adjusting the amount of $CH_4$ and $H_2$ as the source gas. The optical and mechanical properties of DLC films were characterized by UV spectrometer, Ellipsometer and Nano-indenter. The change of the C/H ratio during synthesis of DLC films had many effects on the growth rate, transmittance, refractive index and hardness. The growth rate of the films increased exponentially with the increase in C/H ratio. The hardness of the films showed the tendency to improve with increasing C/H ratio, whereas the transmittance decreased. The refractive index was varied from 2.03 to 2.17, and these refractive indexes close to 2.0 indicates that it can be applied to Si-based solar cell.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.339-339
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• 2013

We study on the optical and electrical properties of indium-free ZTO(ZnSnO)/Ag/ZTO (ZAZ) multilayer electrodes for the low-cost transparent electrode. In the first step, each single layer was deposited using rf magnetron in-line sputter with various working pressure based on $O_2$/$Ar+O_2$ ratio (0~3%) and power at room temperature. Secondly, we studied the optical and electrical properties by analyzing the refractive index, extinction coefficient, transmittance and resistivity of each layer. Finally, we optimized the thickness of each layer using macleod simulation program based on the analyzed optical properties and fabricated the multilayer electrode. As a result, We achieved a low sheet resistance of $11{\Omega}$/sq and anaverage transmittance of 80% in the visible region of light (380~780 nm). This indicates that indium-free ZAZ multilayer electrode is a promising low-cost and low-temperature processing electrode scheme.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.10
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• pp.850-853
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• 2009

We have optimized the device structure by using the dielectric layer such as anti-reflection thin film to improve the emitting efficiency of white organic light emitting device (WOLED). Basically, dielectric layer with anti-reflection characteristics can enhance the emitting efficiency of WOLED by compensating the refractive index of organic layer, ITO, and Glass. Here, WOLED was designed and optimized by Macleod simulator. The refractive index of 1.74 was calculated for Dielectric layer and was selected as $TiO_2$. The optimal thicknesses of $TiO_2$ and ITO were 119.3 and 166.6 nm, respectively, at the wavelength of 600 nm. The transmittance of ITO was measured with the thickness variation of dielectric layer and ITO in Organic layer/ITO/Dielectric layer structure. The transmittance of ITO was 95.17% and thicknesses of $TiO_2$ and ITO were 119.3 and 166.6 nm, respectively. This result, calculated and measured values were coincided.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.11
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• pp.78-84
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• 1998

Refractive index was matched using the inhomogeneous dielectric layers to enhance the optical transmittance of surface discharge type AC PDP. The transmittance of upper panel which had two index-matched inhomogeneous dielectric layers was measured as 85%, and this result is regarded as 15% better transmittance than that of conventional structure, which is about 70%.

• Korean Journal of Optics and Photonics
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• v.35 no.1
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• pp.1-8
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• 2024

Explicit expressions for the transmission pseudo-ellipsometric constants and transmittance of a semi-transparent glass substrate coated with thin films are presented to determine the optical constants of a very weakly absorbing thin film coated on a glass substrate. The intensity of the multiply reflected light inside the semi-transparent substrate is superposed incoherently and the light absorption by the substrate is properly treated, so that modeling analysis of thin films coated on a semi-transparent substrate can be performed with increased accuracy. The extinction coefficient derived from transmittance analysis is compared to that from ellipsometric analysis in the weakly absorbing region, and the difference between the two extinction coefficients is discussed in relation to the sensitivities of the transmittance and ellipsometric constants. This transmittance analysis, together with ellipsometric analysis, is applied to a glass substrate coated with a SiN thin film, and it is shown that the thickness and complex refractive index of the SiN thin film can be determined accurately, even though the extinction coefficient is very small.

• Journal of the Optical Society of Korea
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• v.10 no.1
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• pp.1-10
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• 2006

Optical transparency and high diffraction efficiency are two essential factors for high performance of the photopolymer. Optical transparency mainly depends on the miscibility between polymer binder and photopolymerized polymer, while diffraction efficiency depends on the refractive index modulation between polymer binder and photopolymerized polymer. For most of organic materials, the large refractive index difference between two polymers accompanies large structural difference that leads to the poor miscibility and thus poor optical quality via light scattering. Therefore, it is difficult to design a high-performance photopolymer satisfying both requirements. In this work, first, we prepared a new phase-stable photopolymer (PMMA) with large refractive index modulation and investigated the optical properties. Our photopolymer is based on modified poly (methyl methacrylate) as a polymer binder, acryl amide as a photopolymerizable monomer, triethanolamine as initiator, and yellow eosin as a photosensitizer at 532 nm. Diffraction efficiency over 85% and optical transmittance over 90% were obtained for the photopolymer. Second, Organic-inorganic nanocomposite films were prepared by dispersing an aromatic methacrylic monomer and a photo- initiator in organic-inorganic hybrid sol-gel matrices. The film properties could be controlled by optimizing the content of an organically modified silica precursor (TSPEG) in the sol-gel matrices. The photopolymer film modified with the organic chain (TSPEG) showed high diffraction efficiency (> 90%) under an optimized condition. High diffraction efficiency could be ascribed to the fast diffusion and efficient polymerization of monomers under interference light to generate refractive index modulation. The TSPEG modified photopolymer film could be successfully used for holographic memory.

• Journal of the Korean Chemical Society
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• v.55 no.1
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• pp.98-103
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• 2011

This study was done for the preparation of macromolecular material with UV-blocking features by adding the benzophenone group that is commonly used as a UV-absorbent and $TiO_2$ which is known to be a very stable material in chemical and physical aspects. Also, we compared the level of UV absorbency of the polymer produced from polymerization with previous materials and measured basic properties such as water content, refractive index and optical transmittance of produced contact lenses. The results of the measurement showed that the refractive index and water content of the contact lens with added UV-absorbent was 1.430~1.440 and 35.0~45.0% respectively, which was similar to that of previous contact lenses. Also, for optical transmittances of each wave length, contact lenses without the UV-absorbent was 89%, 88% and 89% respectively for UV-A, UV-B and visible light, indicating that the UV transmittance is very high though contrary with cases of contact lenses with added 2-hydroxy-4-methoxy-benzophenone and 2,4-dihydroxy-benzophenone which showed transmittances of 0% and 6% respectively for UV-A and UV-B showing a UV-blocking effect. Meanwhile, contact lenses with added $TiO_2$ showed transmittance of 6% and 51% respectively for UV-A and UV-B also showing a UV-blocking effect. The visible transmittance was 77~89% showing that it satisfies the visible transmittance required for ophthalmological materials.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.367-367
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• 2013

Commercial applications of indium tin oxide (ITO) can be separated into two useful areas. As it is perceived to bear electrical properties and optical transparency at once, its chance to apply to promising fields, usually for an optical device, gets greater in the passing time. ITO is one of the transparent conducting oxides (TCO), and required to carry the relative resistance less than $10^{-3}{\Omega}$/cm and transmittances over 80 % in the visible wavelength of light. Because ITO has considerable refractive index, there exist applications for anti-reflection coatings. Anti-reflection properties require gradual change in refractive index from films to air. Such changes are obtained from film density or nano-clustered fractional void. Glancing angle deposition (GLAD) method is a well known process for adjusting nanostructure of the films. From its shadowing effects, GLAD helps to deposit well-controlled porous films effectively. In this study, we are comparing the reference sample to samples coated with controlled ITO multilayer accumulated by an e-beam evaporation system. At first, the single ITO layer samples are prepared to decide refractive index with ellipsometry. Afterwards, ITO multilayer samples are fabricated and fitted by multilayer ellipsometric model based on single layer data. The structural properties were measured by using atomic force microscopy (AFM), and by scanning X-ray diffraction (XRD) measurements. The ellipsometry was used to determine refractive indices and extinction coefficient. The optical transmittance of the film was investigated by using an ultraviolet-visible (UV-Vis) spectrophotometer.

• Journal of the Korean institute of surface engineering
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• v.29 no.6
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• pp.781-787
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• 1996

Silicom oxide films with good water repellency were prepared by rf plasma-enhanced CVD (rf-PECVD) using four kinds of organosilicon compound, which had different number of methyl ($CH_3$) groups, and oxygen as gas sources. The differences in the deposition rates, film composition and film properties were studied in detail. Water repellency depended on the number of $CH_3$ groups in the organosilicon compounds and the partial pressure of oxygen in the plasma. The highest contact angle for water drops, about 95 degrees, was obtained when trimethy lmethoxy silane (TMMOS) was used. The contact angle decreased with the amount of oxygen gas introduced into the plasma. The dissociation of $CH_3$ groups by adding oxygen was comfirmed by Fourier transform infrared spectroscopy(FTIR) and X-ray photoelectron spectroscopy (XPS). The optical properties were estimated by double-beam spectroscopy and ellipsometry. The transmittance of the glass plate coated by the film prepared with tetramethoxy silane (TMOS) was about 90% and the refractive index of film was 1.44. This value was smaller than the refractive index of a glass plate(soda lime glass, refractive index is 1.515) and this film played a role of anti-refractive coating.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.1
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• pp.57-61
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• 2002

Ternary $SrO-B_2O_3-SiO_2$ glasses were fabricated as a function of R(${\equiv}SrO\;mole%/B_2O_3\;mole%$) and K(${\equiv}SiO_2\;mole%/B_2O_3\;mole%$). The structures of these glasses were investigated through Infrared transmittance, vicker's hardness, and refractive index. The results indicated : First, in the infrared transmittance spectra, when R increased, the intensities of the absorption bands around $1200{\sim}1600cm^{-1}$ resulting from the B-O stretching vibration bond in the symmetrical trigonal $BO_3$ units decreased, and these of the absorption bands around $800{\sim}1200cm^{-1}$ caused by the B-O stretching vibration bond of the tetrahedral $BO_4$ units varied. Also, the intensities of the absorption bands for the B-O stretching vibration bond in trigonal $BO_3$ units increased and these of the bands for B-O stretching vibration bond in tetrahedral $BO_4$ units decreased as K increased. Second, the increase and the decrease of vicker's hardness values for these glasses depended on the fraction of $BO_4$ units and it of $BO_3$ units, respectively. The refractive index of these glasses mostly depended on the SrO contents and only slightly depended on the fraction of $BO_4$ and $BO_3{^-}$ units.