• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.163.1-163.1
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• 2016

Lead halide perovskites CH3NH3PbX3 (X=Cl, Br, I) have received great interest in the past few years because of their excellent photoelectronic properties as well as their low-cost solution process. Their theoretical efficiency limit of the solar cell devices was predicted around 31% by a detailed balance model for the reason that exceptional light-harvesting and superior carrier transport properties. Additionally, these excellent properties contribute to the applications of optoelectronic devices such as LASERs, LEDs, and photodetectors. Since these devices are mainly using perovskite thin film, one of the most important factor to decide the efficiency of these applications is the quality of the film. Even though, optoelectrical devices are composed of polycrystalline thin film in general, not a single crystalline form which has longer carrier diffusion length and lower trap density. For these reasons, monodomain perovskite thin films have potential to elicit an optimized device efficiency. In this study, we analyzed the crystallography of the in-plane aligned perovskite thin film by X-ray diffraction (XRD) and selected area electron diffraction (SAED). Also the basic optic properties of perovskites were checked using scanning electron microscopy (SEM) and UV-Vis spectrum. From this work, the perovskite which is aligned in all directions both of out-of-plane and in-plane was fabricated and analyzed.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.4
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• pp.176-179
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• 2005

The increasing demand for high density packaging technologies and the evolution to mixed digital and analogue devices has been the con-set of increasing research in thin film multi-layer technologies such as the passive components integration technology. In this paper, Cu and TaO thin film with RF sputtering was deposited for spiral inductor and MOM capacitor on the $SiO_2$/Si(100) substrate. MOM capacitor and spiral inductor were fabricated for L-C band pass filter by sputtering and lift-off. We are analyzed and designed thin films L-C passive components for band pass filter at 900 MHz and 1.8 GHz, important devices for mobile communication system. Based on the high-Q values of passive components, MOM capacitor and spiral inductors for L-C band pass filter, a low insertion loss of L-C passive components can be realized with a minimized chip area. The insertion loss was 3 dB for a 1.8 GHz filter, and 5 dB for a 900 MHz filter. This paper also discusses a analysis and practical design to thin-film L-C band pass filter.

• Journal of information and communication convergence engineering
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• v.4 no.3
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• pp.111-113
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• 2006

A new thin film deposition technique of piezoelectric ZnO film and its successful application for film bulk: acoustic resonator (FBAR) devices are presented. The two-step deposition used seems to be able to deposit ZnO film with a highly preferred orientation. The FBAR devices with the ZnO films show an excellent return loss of $35{\sim}50$ dB at $1.5{\sim}2$ GHz.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.365.1-365.1
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• 2014

Cobalt oxide has excellent various properties such as high catalytic activity, antiferromagnetism, and electrochromism. So cobalt oxides offer a great potential for their applications in the various areas such as optical gas sensor, catalysts for oxidation reaction, electrochromic devices, high temperature solar selective absorbers, magnetic materials, pigment for glasses and ceramics, and negative electrodes for lithium-ion batteries. We have synthesized novel cobalt complexes by simple reaction of cobalt bistrimethylsilylamide as a starting material with a lot of conventional ligands as potential cobalt oxide precursors. The studies include the facile preparation, structural characterization, and spectroscopic analysis of the new precursors. We are making efforts to grow cobalt oxide thin films using cobalt complexes newly synthesized in this study using deposition techniques.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.598-601
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• 1999

There is currently considerable interest in the applications of conjugated polymers, oligomers and small molecules for thin-film electronic devices. Organic materials have potential advantages to be utilized as semiconductors in field effect transistor and light emitting didoes. In this study, Pentacene thin film transistors(TFTs) were fabricated on glass substrate. Aluminum and Gold wei\ulcorner used fur the gate and source/drain electrodes. Silicon dioxde was deposited as a gate insulator by PECVD and patterned by R.I.E. The semiconductor layer of pentacene was thermally evaporated in vaccum at a pressure of about 10$^{-8}$ Torr and a deposition rate 0.3$\AA$/sec. The fabricated devices exhibited the field-effect mobility as large as 0.07cm$^2$/Vs and on/off current ratio larger than 10$^{7}$

• Korean Journal of Metals and Materials
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• v.48 no.12
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• pp.1064-1069
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• 2010

Thin films have been used in a large variety of technological applications such as solar cells, optical memories, photolithographic masks, protective coatings, and electronic contacts. If thin films experience frequent temperature changes, thermal stresses are generated due to the difference in the coefficient of thermal expansion between the film and substrate. Thermal stresses may lead to damage or deformation in thin film used in electronic devices and micro-machined structures. Thus, knowledge of the thermomechanical properties of thin films, such as the coefficient of thermal expansion, is an important issue in determining the stability and reliability of the thin film devices. In this study, thermal cycling of Cu and Ag thin films with various microstructures was employed to assess the coefficient of thermal expansion of the films. The result revealed that the coefficient of thermal expansion (CTE) of the Cu and Ag thin films increased with an increasing grain size. However, the effect of film thickness on the CTE did not show a remarkable difference.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.234-234
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• 2003

Indium tin oxide(ITO) is an advanced ceramic material with many electronic and optical applications due to its high electrical conductivity and transparency to light ITO thin films are used in transparent electrodes for display devices, transparent coatings for solar energy heat mirrors and windows films in n-p heterojunction solar cells, etc. Almost all display devices were fabricated on transparent ITO electrode substrates. There are several factors that cause decay in the efficiency and the failure of display devices. The degradation or damage of ITO is one of the main factors. Under normal operating conditions, the electric fold required for the operation of display devices is very high As a high electric field induces the joule heat, the degradation of the ITO thin film may be expected. Therefore, it is worthy to investigate the thermal and electrical effect on ITO thin films.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.754-758
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• 2002

In order to reach the high quality of organic thin films such as high mobility for device applications, it is strongly desirable to study the growth properties of pentacene film as a function of evaporation condition. Here, we report the structure and morphology of thermal evaporated pentacene thin film by AFM, SEM, and XRD as a function of the evaporation rate and substrate temperature. These results play a key role in determining the electric performance of organic thin film transistor devices.

• Mass Spectrometry Letters
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• v.12 no.1
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• pp.26-30
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• 2021

The impurity concentration is a crucial parameter for semiconductor thin films. Evaluating the impurity distribution in silicon thin film is another challenge. In this study, we have investigated the doping concentration of boron in silicon thin film using time of flight secondary ion mass spectrometry in dynamic mode of operation. Boron doped silicon film was grown on i) p-type silicon wafer and ii) borosilicate glass using hot wire chemical vapor deposition technique for possible applications in optoelectronic devices. Using well-tuned SIMS measurement recipe, we have detected the boron counts 101~104 along with the silicon matrix element. The secondary ion beam sputtering area, sputtering duration and mass analyser analysing duration were used as key variables for the tuning of the recipe. The quantitative analysis of counts to concentration conversion was done following standard relative sensitivity factor. The concentration of boron in silicon was determined 1017~1021 atoms/㎤. The technique will be useful for evaluating distributions of various dopants (arsenic, phosphorous, bismuth etc.) in silicon thin film efficiently.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.06a
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• pp.121-124
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• 1997

Emergence of advanced materials has been realized by the great demands for sophisticated state devices in high technology industry. It is the ear of speedy evolution of science and technology, in particular, materials processing technology, which enables us to synthesize any materials with respect to its purity and its perfection of crystal structure and shape (form) that have, heretofore not been available. The availability of ultra pure, fine raw materials, single crystals and thick/thin film materials has been largely responsible for such startling progresses that have been made in the realization of unforeseen, functional devices for high technology industry. Of the functional devices such as passive as active devices, non-silicon devices are mostly passive. Piezoelectric, electro-optic, magneto-optic devices, etc. are some of the examples. In this paper, magneto-optic materials for Faraday device, which is little known, are reviewed including its processing toward practical applications.