• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 C
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• pp.1433-1435
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• 1997

ZnO shows the properties of wide conductivity variation, high optical transmittance, and excellent piezoelectricity. Using these properties of ZnO, the material applications were extended to sensors, SAW filters, solar cells, and display devices. This paper investigated transmittance influencing factors for thin film ZnO grown by RF magnetron sputtering. The growth rate and structural investigation were carried out in conjunction with optical transmittance characteristics of thin film ZnO. The glass substrate temperature of $175^{\circ}C$ exhibited a preferential crystallization along (002) orientation. Transmittance of ZnO film deposited at the substrate temperature of $175^{\circ}C$ showed higher than 92%. An active sputter gas was investigated with a variation of $O_2$ partial pressure from 0 to 10% in an Ar atmosphere. ZnO film grown in 100% Ar gas shows that a reduced transmittance of 82% at the short wavelengths and decreased resistivity value. As the partial pressure of $O_2$ gas increased, the optical transmittance was increased above 90% at the short wavelengths, however, resistivity was drastically increased to higher than $10^4{\Omega}$-cm.

• 한국정보통신학회논문지
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• 제7권4호
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• pp.712-718
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• 2003

진공 증착한 CdS 박막의 질소 이온 주입 효과를 X-선 회절 검사, 광 투과율, 라만 산란 특성을 통하여 조사하였다. 질소 이온 주입하지 않은 CdS 박막은 (0 0 2)면으로의 우선 방위를 가지고 성장하였다. 질소 이온 주입한 시편의 경우 metallic Cd가 형성됨을 XRD 분석 결과 알 수 있었다. 가시광 영역에서의 광투과율은 질소 이온 주입 양이 많아짐에 따라 크게 감소하였다. 또한 질소 이온 주입 양에 따라 CdS 박막의 흡수 계수는 지수 함수적으로 증가하였고, 밴드 갭은 감소하였다 CdS 박막의 라만 peak 위치는 질소 이온 주입 양에 관계없이 299 cm-1로 거의 일정하지만, peak의 FWHM은 이온 주입 양이 증가함에 따라 커졌고, peak 면적은 감소하였다.

• 한국전기전자재료학회논문지
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• 제25권2호
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• pp.121-124
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• 2012

The characteristics of Ga-doped zinc oxide (GZO) thin films deposited at different deposition temperatures (TS~250 to $550^{\circ}C$) on 4H-SiC have been investigated. Structural and electrical properties of GZO thin film on n-type 4H-SiC(0001) were investigated by using x-ray diffraction(XRD), atomic force microscopy(AFM), Hall effect measurement, barrier height from I-V curve and Auger electron spectroscopy(AES). XRD $2\theta$ scan shows GZO thin film has preferential orientation with c-axis perpendicular to SiC substrate surface. The lowest resistivity ($\sim1.9{\times}10^{-4}{\Omega}cm$) was observed for the GZO thin film deposited at $400^{\circ}C$. As deposition temperature increases, barrier height between GZO and SiC was increased. Whereas, resistivity of GZO thin films as well as barrier height between GZO and SiC were increased after annealing process in air atmosphere. It has been found that the c-axis oriented crystalline quality as well as the relative amount of activated Ga3+ ions and oxygen vacancy may affect the electrical properties of GZO films on SiC.

• 한국정보통신학회논문지
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• 제7권5호
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• pp.1032-1037
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• 2003

보론 도핑된 CdS 박막을 chemical bath deposition법으로 증착하고, 도핑농도에 따른 박막의 구조적, 광학적 특성을 조사하였다. 보론 도핑된 CdS 박막은 XRD 분석 결과 (002)면 방향으로 강한 우선성장 방위를 가지며 육방정(hexagonal) 구조로 성장하였다 보론 도핑에 관계없이 모든 시편은 2.3 eV(녹색 발광) 및 1.6 eV(적색 발광) 부근에서 PL peak을 가지며, 도핑 농도가 증가함에 따라 피크 세기는 감소하였다. 보론 도핑에 따라 CdS 박막의 가시광 영역에서의 광투과율은 향상되었고, 밴드 갭은 증가하였다.

• 한국전기전자재료학회논문지
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• 제26권9호
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• pp.701-706
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• 2013

We have focused on the conversion efficiency of CIGS thin film solar cell prepared by co-evaporation method as well as the optimization of process condition. The total thickness of back electrode was fixed at 1 ${\mu}m$ and the structural, electric and optical properties of CIGS thin film were investigated by varying the thickness of Mo:Na bottom layer from 0 to 500 nm. From the experimental results, the content of Na was appeared as 0.28 atomic percent when the thickness of Mo:Na layer was 300 nm with compactly densified plate-shape surface morphology. From the XRD measurements, (112) plane was the strongest preferential orientation together with secondary (220) and (204) planes affecting to the crystallization. The lowest roughness and resistivity were 2.67 nm and 3.9 ${\Omega}{\cdot}cm$, respectively. In addition, very high carrier density and hole mobility were recorded. From the optimization of Mo:Na layer, we have achieved the conversion efficiency of 9.59 percent.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.526-529
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• 2002

Various fluoride films on a glass substrate were prepared and characterized in order to determine the best seed layer for a microcrystalline silicon (${\mu}c$-Si) film growth. Among the various group-IIA-fluoride systems, the $CaF_2$films on glass substrates illustrated (220) preferential orientation and a lattice mismatch of less than 0.7% with Si. $CaF_2$ films exhibited a dielectric constant between $4.1{\sim}5.2$ and an interface trap density ($D_{it}$ as low as $1.8{\times}10^{11}\;cm^{-2}eV^1$. Using the $CaF_2$/glass structure, we were able to achieve an improved ${\mu}c$-Si film at a process temperature of 300 $^{\circ}C$. We have achieved the ${\mu}c$-Si films with a crystalline volume fraction of 65%, a grain size of 700 ${\AA}$, and an activation energy of 0.49 eV.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.576-576
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• 2012

High quality single crystalline strain controlled wurtzite ZnO nanowire arrays have been grown on conductive silicon and ITO substrates by a facile hydrothermal method. The diameter of the nanowires was found to be less than 90 nm approximately for both of the two kinds of substrates. The quality of the ZnO nanowire arrays is dramatically improved by hanging the substrate above from the bottom of the Teflon lined autoclave. The structural investigation indicates the preferential orientation of the nanowire along c-axis. In order to make the convincible comparison, the photoluminescence property of the nanowire arrays grown under different conditions are measured, the sharp near band edge emission from PL, low turn-on voltage ($1.9V/{\mu}m$) from field emission measurement and Fowler-Nordheim plot was investigated from ZnO nanowire arrays grown by proposed substrate hanging method.

• 한국표면공학회지
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• 제46권2호
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• pp.75-79
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• 2013

A one-step route was developed to fabricate $Cu(In,Ga)Se_2$ (CIGS) thin films by radio frequency (RF) magnetron sputtering from a single quaternary $CuIn_{0.75}Ga_{0.25}Se_2$ target. The effects of the substrate temperatures on the structural and electrical properties of the CIGS layers were investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS) and Hall effect measurements. All the deposited films showed a preferential orientation along the (112) direction. The films deposited at $300^{\circ}C$ and $400^{\circ}C$ revealed that chalcopyrite main (112) peak and weak prominent peaks of (220)/(204) and (312)/(116), indicating polycrystalline structures. The element ratio of the deposited film at $300^{\circ}C$ were almost the same as the near-optimum value. The carrier concentration of the films decreased with increasing substrate temperatures.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 C
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• pp.1283-1285
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• 1997

In this paper, structural, optical and electrical properties of $Cd_{1-x}Zn_xS$ thin films prepared by co-evaporation method were studied. The crystal structure of $Cd_{1-x}Zn_xS$ films deposited at a substrate temperature of $150^{\circ}C$ was hexagonal with the c axis aligned perpendicular to the substrate. As increasing composition parameter x, the intensity of (002) peak decreased, which means poor crystalline and decreasing of preferential orientation. The optical bandgap of $Cd_{1-x}Zn_xS$ films varies from 2.41eV for CdS to 3.48eV for ZnS with x. The resistivity of the $Cd_{1-x}Zn_xS$ films increased with x.

• 한국재료학회지
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• 제24권3호
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• pp.123-128
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• 2014

To realize high-performance thin film solar cells, we prepared CIGS by the co-evaporation technique on both sodalime and Corning glass substrates. The structural and efficient properties were investigated by varying the thickness of the Mo:Na layer, where the total thickness of the back contact was fixed at 1${\mu}m$. As a result, when the Mo:Na thickness was 300 nm on soda-lime glass, the measured Na content was 0.28 %, the surface morphology was a plate-like compact structure, and the crystallinity by XRD showed a strong peak of (112) preferential orientation together with relatively intense (220) and (204) peaks as the secondary phases influenced crystal formation. In addition, the substrates on soda-lime glass effected the lowest surface roughness of 2.76 nm and the highest carrier density and short circuit current. Through the optimization of the Mo:Na layer, a solar conversion efficiency of 11.34% was achieved. When using the Corning glass, a rather low conversion efficiency of 9.59% was obtained. To determine the effects of the concentration of sodium and in order to develop a highefficiency solar cells, a very small amount of sodium was added to the soda lime glass substrate.