• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.436-437
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• 2008

Flexible CIGS thin film solar cell was fabricated using STS430 plate as a flexible substrate in this work. A diffusion barrier layer of $SiO_2$ thin film was deposited on STS430 substrate by PECVD followed by deposition of double layered Mo back contact. After depositing CIGS absorber layer by co-evaporation, CdS buffer layer by chemical bath deposition, ZnO window layer by RF sputtering and Al electrode by thermal evaporation, the solar cell fabrication processes were completed and its performance was evaluated. Corresponding solar cell showed an conversion efficiency of 8.35 % with $V_{OC}$ of 0.52 V, $J_{SC}$ of 26.06 mA/$cm^2$ and FF of 0.61.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.115-115
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• 2011

Nano hybrid superlattices consisting of organic and inorganic components have great potential for creation of new types of functional material by utilizing the wide variety of properties which differ from their constituents. They provide the opportunity for developing new materials with new useful properties. Herein, we fabricated new type of organic-inorganic nano hybrid superlattice thin films by a sequential, self-limiting surface chemistry process known as molecular layer depostion (MLD) combined with atomic layer deposition (ALD). An organic layer was formed at $150^{\circ}C$ using MLD with repeated sequintial adsorption of Hydroquinone and Titanium tetrachloride. A $TiO_2$ inorganic nanolayer was deposited at the same temperature using ALD with alternating surface-saturating reactions of Titanium tetrachloride and water. Using UV-Vis spectroscopy, we confirmed visible light absorption by LMCT. And FTIR spectroscopy and XPS were employed to determine the chemical composition. Ellipsometry and TEM analysis were also used to confirm linear growth of the film versus number of MLD cycles at all same temperature. In addition, p-n junction diodes domonstrated in this study suggest that the film can be suitable for n-type semiconductors.

• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.156-157
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• 1998

It is a diffcult and challenging pproblem to control the growth of eppitaxial films. Heteroeppitaxy is esppecially idfficult because of the lattice mismatch between sub-strate and depposited layers. This mismatch leads usually to a three dimensional(3D) island growth. But the use of surfactants such as As, Sb, and Bi can be beneficial in obtaining high quality heteroeppitaxial films. In this study medium energy ion scattering sppectroscoppy(MEIS) was used in order to reveal the growth mode of Ge on Si(001) and the strain of depposited film without and with dynamically supplied atomic hydrogen at the growth thempperature of 35$0^{\circ}C$. It was ppossible to control the growth mode from layer-by-layer followed by 3D island to layer-by-layer by controlling the hydrogen flux. In the absent of hydro-gen the film grows in the layer-by-layer mode within the critical thickness(about 3ML) and the 3D island formation is followed(Fig1). The 3D island formation is suppressed by introducing hydrogen resulting in layer-by-layer growth beyond the critical thickness(Fig2) We measured angular shift of blocking dipp in order to obtain the structural information on the thin films. In the ppressence of atomic hydrogen the blocking 야 is shifted toward higher scattering angle about 1。. That means the film is distorted tetragonally and strained therefore(Fig4) In other case the shift of blocking dipp at 3ML is almost same as pprevious case. But above the critical thickness the pposition of blocking dipp is similar to that of Si bulk(Fig3). It means the films is relaxed from the first layer. There is 4.2% lattice mismatch between Ge and Si. That mismatch results in about 2。 shift of blocking dipp. We measured about 1。 shift. This fact could be due to the intermixing of Ge and Si. This expperimental results are consistent with Vegard's law which says that the lattice constant of alloys is linear combination of the lattic constants of the ppure materials.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.627-630
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• 2002

Bi$_2$Sr$_2$CuOx(Bi-2201) thin films were fabricated by atomic layer-by-layer deposition using an ion bean sputtering method. 10 wt% and 90 wt% ozone mired with oxygen were used with ultraviolet light irradiation to assist oxidation. XRD and RHEED investigations revealed that a buffer layer is formed at the early stage of deposition (less than 10 unit cell), and then c-axis oriented Bi-2201 grows on top of it.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.1
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• pp.53-59
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• 2003

Using Platinum-silicide (PtSi) formed between silicon substrate and carbon film, we have improved the field emission of electrons from carbon films. Pt films were deposited on n-Si(100) substrates at room temperature by DC sputter technique. After deposition, these PtSi thin films were annealed at 400 ~ $600^{\circ}C$ in a vacuum chamber, and the carbon films were deposited on those Pt/Si substrates by laser ablation at room temperature. The field emission property of C/Pt/Si system is found to be better than that of C/Si system and it is showed that property was improved with increasing annealing temperature. The reasons why the field emission from carbon film was improved can be considered as follows, (1)the resistance of carbon films was decreased due to graphitization, (2)electric field concentration effectively occurred because the surface morphology of carbon film deposited on Pt/si substrates with rough surface, (3)it is showed that annealing induced reaction between Pt film and Si substrate, as a consequence that the interfacial resistance between Pt film and Si substrate was decreased.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.5
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• pp.273-277
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• 2018

This research introduces the sputtered IZO thin film transistor (TFT) with solution-processed $Al_2O_3$ diffusion layer. IZO is one of the most commonly used amorphous oxide semiconductor (AOS) TFT. However, most AOS TFTs have many defects that degrade performance. Especially oxygen vacancy in the active layer. In previous research, aluminum was used as a carrier suppressor by binding the oxygen vacancy and making a strong bond with oxygen atoms. In this paper, we use a solution-processed $Al_2O_3$ diffusion layer to fabricate stable IZO TFTs. A double-layer solution-processed $Al_2O_3$-sputtered IZO TFT showed better performance and stability, compared to normal sputtered IZO TFT.

• Journal of the Korean Ceramic Society
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• v.34 no.4
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• pp.373-379
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• 1997

A study on the deposition and characterization of BaTiO3 thin films on MgO-buffered Si(100) substrates by sputtering was conducted. The MgO buffer layers were investigated as a function of deposition temperature. At lower substrate temperature, the MgO layers were not fully crystalline, but a crystallized MgO layer with (001) preferred orientation was obtained at the substrate temperature of $700^{\circ}C$. Partially (00ι) or (h00) textured BaTiO3 films were obtained on Si(100) with the MgO buffer layer grown at 700ι. While, randomly oriented BaTiO3 films with large-scale cracks on the surface were made without the MgO layer. The crystallographic orientation, morphology and electrical properties between the BaTiO3 films on Si with and without the MgO layer were compared using the BaTiO3 film on MgO(100) single crystal substrate as a reference system. Also the favorable role of the MgO layer as a buffer for growing of oriented BaTiO3 films on Si substrates was confirmed.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.312.1-312.1
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• 2016

We have deposited ZnO thin films by ultraviolet (UV) enhanced atomic layer deposition using diethylznic (DEZ) and water (H2O) as precursors with UV light. The atomic layer deposition relies on alternating dose of the precursor on the surface and subsequent chemisorption of the precursors with self-limiting growth mechanism. Though ALD is useful to deposition conformal and precise thin film, the surface reactions of the atomic layer deposition are not completed at low temperature in many cases. In this experiment, we focused on the effects of UV radiation during the ALD process on the properties of the inorganic thin films. The surface reactions were found to be complementary enough to yield uniform inorganic thin films and fully react between DEZ and H2O at the low temperature by using UV irradiation. The UV light was effective to obtain conductive ZnO film. And the stability of TFT with UV-enhanced ZnO was improved than ZnO by thermal ALD method. High conductive UV-enhanced ZnO film have the potential to applicability of the transparent electrode.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.17-20
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• 2001

In this paper, film bulk acoustic resonator(FBAR) with an air-gap is fabricated by removing ZnO sacrificial layer and its characteristics as a various dimension of ZnO sacrificial and piezoelectric layer is evaluated. The center frequency of the FBAR device with the ZnO film is about 1.9 GHz. Because of mass-loading effect, a dimension of sacrificial layer and piezoelectrc layer affect frequency response such as center frequency, insertion loss, band separation, attenuation and so on.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.784-786
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• 2009

Thermal transfer of emitting layer from the donor film to the substrates depends on the physical interaction between the donor film, the emitting layer, and the hole-transport layer (HTL). The interfacial adhesion between the donor film and the EML, the cohesive force of the EML, and the interfacial adhesion between the EML and the HIL have to be optimized to achieve good LITI pattern quality. It was found that surface pretreatment of the donor plate was important on the laser induced thermal transfer of the emitting layer onto the HIL layer of the OLED devices.