• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.12
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• pp.1135-1140
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• 2008

Bismuth-telluride based thin film materials are grown by Metal Organic Chemical Vapor Deposition(MOCVD). A planar type thermoelectric device has been fabricated using p-type $Bi_{0.4}Sb_{1.6}Te_3$ and n-type $Bi_2Te_3$ thin films. Firstly, the p-type thermoelectric element was patterned after growth of $4{\mu}m$ thickness of $Bi_{0.4}Sb_{1.6}Te_3$ layer. Again n-type $Bi_2Te_3$ film was grown onto the patterned p-type thermoelectric film and n-type strips are formed by using selective chemical etchant for $Bi_2Te_3$. The top electrical connector was formed by thermally deposited metal film. The generator consists of 20 pairs of p- and n-type legs. We demonstrate complex structures of different conduction types of thermoelectric element on same substrate by two separate runs of MOCVD with etch-stop layer and selective etchant for n-type thermoelectric material. Device performance was evaluated on a number of thermoelectric devices. To demonstrate power generation, one side of the sample was heated by heating block and the voltage output measured. As expected for a thermoelectric generator, the voltage decreases linearly, while the power output rises to a maximum. The highest estimated power of $1.3{\mu}W$ is obtained for the temperature difference of 45 K. we provide a promising procedure for fabricating thin film thermoelectric generators by using MOCVD grown thermoelectric materials which may have nanostructure with high thermoelectric properties.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.52-52
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• 2011

A novel deposition process for n-type nanocrystalline silicon (n-type nc-Si) thin films at room temperature has been developed by adopting the neutral beam assisted chemical vapor deposition (NBa-CVD). During formation of n-type nc-Si thin film by the NBa-CVD process with silicon reflector electrode at room temperature, the energetic particles could induce enhance doping efficiency and crystalline phase in polymorphous-Si thin films without additional heating on substrate; The dark conductivity and substrate temperature of P-doped polymorphous~nano crystalline silicon thin films increased with increasing the reflector bias. The NB energy heating substrate(but lower than $80^{\circ}C$ and increase doping efficiency. This low temperature processed doped nano-crystalline can address key problem in applications from flexible display backplane thin film transistor to flexible solar cell.

• Journal of the Korean Ceramic Society
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• v.46 no.6
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• pp.673-678
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• 2009

The effect of MgO buffer layer on the structural properties of sputter-grown ZnO thin film was investigated. Sapphire (0001) and Si (100) substrate were used for the growth and MgO buffer layer was inserted between ZnO thin film and the substrate. X-ray diffraction pattern indicated that enhanced crystallinity in the ZnO thin film grown was achieved by inserting very thin MgO buffer layer, regardless of the substrate type. The strain in the ZnO thin film could also be controlled by the insertion of the MgO buffer layer, and tendency of the strain was strongly dependent on the substrate type.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.432-433
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• 2006

Electro-optical (EO) characteristics of twisted nematic (TN) - liquid crystal display (LCD) on the NDLC thin film using obliquely ion beam (IB) exposure as new ion beam (IB) type system (DuoPIGatrion ion source). A good uniform alignment of the nematic liquid crystal (NLC) alignment with the ion beam exposure on the NDLC thin film was observed. In addition, it can be achieved the good EO properties of the ion-beam-aligned TN-cell on polyimide surface ; the stable VT curve in the ion-beam-aligned TN cell on the NDLC thin film with ion beam exposure using new type IB equipment was obtained. and the fast response time in the ion-beam-aligned TN cell on the NDLC thin film with ion beam exposure using new type IB equipment was obtained.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.703-706
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• 2002

Piezoelectric thin film such as ZnO and AlN can be applicable to FBAR (Film Bulk Acoustic Resonator) device of thin film type and FBAR can be applicable to MMIC. The characteristic of FBAR device is variable according to the deposition conditions of piezoelectric thin film when preparation of thin film by sputtering method. In this study, we prepared ZnO thin film for FBAR using Facing Targets Sputtering apparatus which can be deposited fine Quality thin film because temperature increase of substrate due to the bombardment of high-energy particles can be restrained. And crystalline and c-axis preferred orientation of ZnO thin film with deposition conditions was investigated by XRD.

• Journal of Sensor Science and Technology
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• v.9 no.6
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• pp.430-439
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• 2000

$In_2O_3$-based thin film sensor with 500-600 nm thick was fabricated for the detection of CO gas by rf magnetron sputtering. In order to improve both sensitivity to CO gas and selectivity to hydrogen gas containing -CH, ultra-thin transition metal Co catalyst was sputtered over $In_2O_3$ thin film and annealed at $500^{\circ}C$. Sensitivity to CO was maximum at the thickness of Co 2.1 nm and $300^{\circ}C$, and that to $C_3H_8$ was at the thickness of Co 1.4 nm and $350-400^{\circ}C$. From the x-ray photoelectron spectroscopy (XPS) result, ultra-thin Co was existed into CoO covered with $Co_2O_3$ on $In_2O_3$ particles, and thus p-n junction of $In_2O_3(n-type)$-CoO(p-type) was thought to be formed. In this p-n junction type sensors, sensing mechanism with reducing gases can be explained by the variation of depletion layer thickness formed in the interface.

• Korean Journal of Materials Research
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• v.6 no.7
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• pp.678-683
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• 1996

In the fabrication processes of thin film thermoelectrics, a subsequent annealing treatment is inevitable to reduce the defects and residual stresses introduced during the film growth, and to make the uniform carrier concentration of the film. However, the diffusion-induced atomic redistribution and the broadening of p/n junction region are expected to affect the thermoelectric properties of thin film modules. The present study intends to investigate the diffusion at the p/n junctions of thermoelectric thin films and to relate it to the property changes. The film junctions of p-type(Bi0.5Sb1.5Te3)and n-type(Bi2Te2.4Se0.6)were prepared by the flash evaporation method. Aluminum thin layer was employed as a diffusion barrier between p-and n-type films of the junction. This was found to be an effective barrier by showing a negligible diffusion into both type films. After annealing treatment, the thermoelectric properties of p/n couples with aluminum barrier layer were accordingly retained their properties without any deterioration.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.860-863
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• 2007

ZnO nano film for transparent thin film transistors is prepared by injection type source delivery system of atomic layer deposition. By using this delivery system the source delivery pulse time can dramatically be reduced to 0.005s in ALD system. ZnO nanofilms obtained at $150^{\circ}C$ are characterized.

• Journal of the Korean Graphic Arts Communication Society
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• v.14 no.1
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• pp.1-15
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• 1996

In this paper, the preparation of lead zirconium titanate(PZT) thin film by sol-gel processing was descried. Thin film coated with thickness of 4${\mu}{\textrm}{m}$ on the stainless steel substrates using the multiple spin-coating process. The crystalline phases of PZT powder and film were investigated by X-ray diffraction pattern and PZT thin film has perovskite structure over 600 C annealing temperature. Corona charging characteristics of the ferroelectric PZT thin film at 600 C were investigated by electrophotographic measurement. A difference in the charging characteristics between positive and negative corona charging was found. The charge acceptance depended in the polarity of corona and the poling of film. According to the D-E hysteresis measurment, PZT thin film can be poled by corona charging without use of top electrode. The remnant polarization in the PZT thin film is generally in the order of 48$\mu$C/$\textrm{cm}^2$. From this results, the ferroelectric PZT thin film will be possible to apply for the add-on type imaging formation.

• Journal of the Korean institute of surface engineering
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• v.49 no.1
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• pp.40-45
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• 2016

Recently, $Bi_2Te_3$-based alloys are the best thermoelectric materials near to room temperature, so it has been researched to achieve increased figure of merit(ZT). Ternary compounds such as Bi-Te-Se and Bi-Sb-Te have higher thermoelectric property than binary compound Bi-Te and Sb-Te, respectively. Compared to DC plating method, pulsed electrodeposition is able to control parameters including average current density, and on/off pulse time etc. Thereby the morphology and properties of the films can be improved. In this study, we electrodeposited n-type ternary Cu-doped $Bi_2(Te-Se)_3$ thin film by modified pulse technique at room temperature. To further enhance thermoelectric properties of $Bi_2(Te-Se)_3$ thin film, we optimized Cu doping concentration in $Bi_2(Te-Se)_3$ thin film and correlated it to electrical and thermoelectric properties. Thus, the crystal, electrical, and thermoelectric properties of electrodeposited $Bi_2(Te-Se)_3$ thin film were characterized the XRD, SEM, EDS, Seebeck measurement, and Hall effect measurement, respectively. As a result, the thermoelectric properties of Cu-doped $Bi_2(Te-Se)_3$ thin films were observed that the Seebeck coefficient is $-101.2{\mu}V/K$ and the power factor is $1412.6{\mu}W/mK^2$ at 10 mg of Cu weight. The power factor of Cu-doped $Bi_2(Te-Se)_3$ thin film is 1.4 times higher than undoped $Bi_2(Te-Se)_3$ thin film.