• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.81-81
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• 2008

Applications of CdS films in this study are to exhibit a high conductivity when they are exposed at light with visible wavelength and sequentially to show a low conductivity in dark state. For this purpose, CdS films should have a high photosensitivity, still maintaining a high conductivity at a visible light. In this study, CdS films were prepared at room temperature on glass substrates by rf magnetron sputtering. In order to increase the photo-conductivity in visible light, various defect levels should be located within the CdS band gap. In order to nucleate the defect sites within the CdS band gap, CdS films were deposited on glass substrates at room temperature using various $H_2$/(Ar+$H_2$) flow ratios by an rf magnetron sputtering. Through the investigation of the structural and photoconductive properties of CdS films by an addition of hydrogen, the relationship between photo- and dark-resistance in CdS films was investigated in detail. 200-nm-thick CdS films for photoconductive sensor applications were prepared at various $H_2$/(Ar+$H_2$) flow ratios on glass substrates at room temperature by rf magnetron sputtering. Sulfur concentration in CdS films crystallized at room temperature with (002) preferred orientation depends directly on the hydrogen atmosphere and the surface roughness of the films gradually increases with increasing hydrogen atmosphere. Films deposited at 8% of $H_2$/(Ar+$H_2$) exhibit an abrupt decrease of dark- and photo-resistance, showing a low photo-sensitivity ($R_{dark}/R_{photo}$). Onthe other hand, films deposited at a hydrogen atmosphere of 42% exhibit a photo-sensitivity of $5\times10^3$, maintaining a photo-resistance of an approximately $2\times10^4\Omega$/square. The dark- and photo-resistance values of CdS films were related with a composition, surface roughness, and defect sites within the band gap.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.305.2-305.2
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• 2016

Tin monosulfide (SnS) is one promising candidate absorber material which replace the current technology based on cadmium telluride (CdTe) and copper indium gallium sulfide selenide (CIGS) for its suitable optical band gap, high absorption coefficient, earth-abundant, non-toxic and cost-effective. During past years work, thin film solar cells based on SnS films had been improved to 4.36% certified efficiency. In this study, Tin monosul fide was obtained by atomic layer deposition (ALD) using the reaction of Tetrakis (dimethylamino) tin (TDMASn, [(CH3)2N]4Sn) and hydrogen sulfide (H2S) at low temperatures (100 to 200 oC). The direct optical band gap and strong optical absorption of SnS films were observed throughout the Ultraviolet visible spectroscopy (UV VIS), and the properties of SnS films were analyzed by sanning Electron Microscope (SEM) and X-Ray Diffraction (XRD).

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.5
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• pp.630-634
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• 2016

We report the computer aided design results for a GaSb/InAs broken-gap gate all around nanowire tunneling FET (TFET). In designing, the semi-empirical tight-binding (TB) method using $sp3d5s^*$ is used as band structure model to produce the bulk properties. The calculated band structure is cooperated with open boundary conditions (OBCs) and a three-dimensional $Schr{\ddot{o}}dinger$-Poisson solver to execute quantum transport simulators. We find an device configuration for the operation voltage of 0.3 V which exhibit desired low sub-threshold swing (< 60 mV/dec) by adopting receded gate configuration while maintaining the high current characteristic ($I_{ON}$ > $100 {\mu}A/{\mu}m$) that broken-gap TFETs normally have.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.13-16
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• 2001

반도체 동작시에 파워 손실을 최소화하는 것은 2000년대의 에너지, 산업전자, 정보통신 산업분야에서의 가장 주요한 요구 사항중의 하나이다. 실리콘계 반도체 소자들은 완전히 새로운 구동기구의 소자가 개발되지 않는 한, 실리콘 재료의 낮은 열전도율이나 낮은 절연파괴전계와 같은 물리적 특성한계 때문에 이러한 요구를 만족시키는 것이 불가능한 실정이다. 따라서 21세기를 위한 대안으로 고열전도융의 WBG(WideBand-Gap) 물질 그 중에서도 탄화규소(SiC) 반도체가 제시되고 있다. SiC 반도체는 실리콘에 비하여 밴드갭(band gap: $E_{g}$)이 높을 뿐만이 아니라 절연파괴강도 ($E_{B}$)가 한 자릿수 이상 그리고 전자의 포화 drift 속도, $V_{s}$ 및 열전도도 k가 3배 가량 크다. 따라서 SiC는 고온 동작 내지는 고내압, 대전류, 저손실 반도체를 제작하는데 아주 유리하다. 본고에서는 응용성이 넓고, 단결정 제조가 비교적 용이한 SiC 반도체의 기술현황에 대하여 살펴보고자 한다.

• Electrical & Electronic Materials
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• v.14 no.12
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• pp.11-14
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• 2001

반도체 동작시에 파워 손실을 최소화하는 것은 2000년대의 에너지, 산업전자, 정보통신 산업분야에서의 가장 주요한 요구 사항중의 하나이다. 실리콘계 반도체 소자들은 완전히 새로운 구동기구의 소자가 개발되지 않는 한, 실리콘 재료의 낮은 열전도율이나 낮은 절연파괴전계와 같은 물리적 특성한계 때문에 이러한 요구를 만족시키는 것이 불가능한 실정이다. 따라서 21세기를 위한 대안으로 고열전도율의 WBG(Wide Band-Gap) 물질 그 중에서도 탄화규소(SiC) 반도체가 제시되고 있다. SiC 반도체는 실리콘에 비하여 밴드 갭(band gap: E$_{g}$)이 높을 뿐만이 아니라 절연파괴강도(E$_{B}$)가 한 자릿수 이상 그리고 전자의 포화 drift 속도, V$_{s}$ 및 열전도도 k가 3배 가량 크다. 따라서 SiC는 고온 동작 내지는 고내압, 대전류, 저손실 반도체를 제작하는데 아주 유리하다. 본고에서는 응용성이 넓고, 단결정 제조가 비교적 용이한 SiC 반도체의 기술현황에 대하여 살펴보고자 한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.307-308
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• 2008

Zinc oxide is a direct band gap wurtzite-type semiconductor with band gap energy of 3.37eV at room temperature. the n-type doped ZnO oxides, B doped ZnO (BZO) is widely studied in TCOs materials as it shows good electrical, optical, and luminescent properties. we focused on the fabrication of B doped ZnO films with glass substrate using the LSMCD at low temperature. And Novel boron-doped ZnO thin films were deposited and characterized from the structural, optical, electrical point of view. The structure, morphology, and optical properties of the films were studied as a function of by employing the XRD, SEM, Hall system and micro Raman system.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.3
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• pp.420-431
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• 1994

The HgCdTe material, which is II-VI compound semiconductor, is important materials for the fabrication of the infrared detectros. To suggest the model of accurate MIS C-V calculation for narrow band gap semiconductors such as HgCdTe, non-parabolicity from k.p theory and degeneracy effect are considered. And partially ionized effect and compensation effect which are material's properties are also considerd. Especially, degenerated material C-V characteristics from Fermi-Dirac statistics and exact charge theory are presented to get more accurate analysis of the experimental results. Also the comparison with calculation results between the general MIS theory from Boltzmann appoximation method and this model which is considered the narrow band gap semiconductor properties, show that this model is more useful theory to determination of accurate low and high frequency C-V characteristics.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.3
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• pp.66-71
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• 1992

We fabricated highly stable a-Si:H solar cell using low band gap intrinsic layer fabricated by RP-CVD. We obtained a-Si:H with optical band gap of less than 1.65 eV with deposition rate of 0.18 $\AA$/sec, and used this material as bottom i-layer of a-Si:H double stacked solar cells. We have succeeded in the fabrication of very stable a-Si:H double stacked solar cell of which the conversion efficiency is about 9% and the degradation is less than 4% after light illumination for 100h under 350mW/cm$^{2}$.

• Journal of the Semiconductor & Display Technology
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• v.10 no.2
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• pp.65-71
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• 2011

Properties of each layer in DSSC were investigated to improve solar cell characterstics. Also in this study, low costsolar simulator system is fabricated and used. Efficiency of DSSC is better in the case of thinner semiconductive layer, because thick semiconductive layer is acted as resistor. Sc-doped ZnO thin films showed better electrical property by proper donor doping effect. Among the dyes, DSSC containing N719 showed higher efficiency, because N719 have smaller electron affinity and shallow band gap.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.13-16
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• 2001

반도체 동작시에 파워 손실을 최소화하는 것은 2000년대의 에너지, 산업전자, 정보통신 산업분야에서의 가장 주요한 요구 사항중의 하나이다. 실리콘계 반도체 소자들은 완전히 새로운 구동기구의 소자가 개발되지 않는 한, 실리콘 재료의 낮은 열 전도율이나 낮은 절연파괴전계와 같은 물리적 특성한계 때문에 이러한 요구를 만족시키는 것이 불가능한 실정이다. 따라서 21세기를 위한 대안으로 고열전도율의 WBG(Wide Band-Gap) 물질 그 중에서도 탄화규소(SiC) 반도체가 제시되고 있다. SiC 반도체는 실리콘에 비하여 밴드 갭(band gap: E$_{g}$)이 높을 뿐만이 아니라 절연파괴강도(E$_{B}$)가 한 자릿수 이상 그리고 전자의 포화 drift 속도, v$_{s}$ 및 열전도도 k가 3배 가량 크다. 따라서 SiC는 고온 동작 내지는 고내압, 대전류, 저손실 반도체를 제작하는데 아주 유리하다. 본고에서는 응용성이 넓고, 단결정 제조가 비교적 용이한 SiC 반도체의 기술현황 에 대하여 살펴보고자 한다.