• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.374-374
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• 2011

Cu(In,Ga)Se2 (CIGS) 박막 태양전지는 일반적으로 Soda lime glass/Mo/CIGS/CdS/ZnO/ITO/Al의 구조로 제작된다. 태양전지는 p형과 n형 반도체의 접합에 의해서 동작을 하게 되며, CIGS 박막 태양전지에서는 p형으로 CIGS 박막과 n형으로 CdS 박막이 사용된다. CIGS 박막태양전지에서는 p형과 n형이 서로 다른 물질로 이루어진 이종접합을 이루게 되고, 계면에서의 밴드가 어떻게 형성이 되느냐에 따라 태양전지 성능에 영향을 미치게 된다. p형의 CIGS 박막은 주로 다단계 증발법에 의해 형성되고 3단계 공정조건에 의해 계면의 특성에 많은 영향을 미치게 된다. n형의 CdS 박막은 주로 chemical bath deposition (CBD) 법에 의해 제작된다. 이렇게 제작되는 CBD-CdS는 시약의 농도, pH (수소이온농도), 박막 형성시의 온도 등의 조건에 따라 특성이 변하게 된다. 본 논문에서는 3단계 공정시간을 변화시켜 제작된 CIGS 박막 위에 CBD-CdS 증착 조건 중 thiourea 의 농도를 변화시켜 CIGS 태양전지를 제작하고 그에 따른 특성을 살펴보았다. CIGS 박막은 3단계 공정시간을 490초와 360초로 하여 제작하였고, CdS 박막은 thiourea 농도를 각각 0.025 M과 0.05 M, 0.074 M, 0.1 M로 변화시켜가며 제작하였다. 제작된 CIGS 박막 태양전지는 CIGS 3단계 공정시간과 thiourea의 조건에 따라 최고 15.81%, 최저 14.13%로 나타내었다. 또한, 외부양자효율을 측정하여 제작된 CIGS 박막 태양전지의 파장에 따른 특성을 비교하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1564-1567
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• 2009

Cu(In,Ga)$Se_2$ (CIGS) thin films were formed using CIGS bulk by electron-beam evaporation method with an evaporation current from 20 mA to 90 mA. The experimental results showed that the chemical compositions and the properties of CIGS films varied with the different evaporation current. The Cu-rich CIGS film was deposited successfully with a band gap of 1.20 eV when the evaporation current was 90 mA.

• 한국재료학회지
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• 제19권8호
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• pp.452-456
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• 2009

In high-efficiency Cu(In,Ga)$Se_2$ solar cells, Na is doped into a Cu(In,Ga)$Se_2$ light-absorbing layer from sodalime-glass substrate through Mo back-contact layer, resulting in an increase of device performance. However, this supply of sodium is limited when the process temperature is too low or when a substrate does not supply Na. This limitation can be overcome by supplying Na through external doping. For Na doping, an NaF interlayer was deposited on Mo/glass substrate. A Cu(In,Ga)$Se_2$ absorber layer was deposited on the NaF interlayer by a three-stage co-evaporation process As the thickness of NaF interlayer increased, smaller grain sizes were obtained. The resistivity of the NaF-doped CIGS film was of the order of $10^3{\Omega}{\cdot}cm$ indicating that doping was not very effective. However, highest conversion efficiency of 14.2% was obtained when the NaF thickness was 25 nm, suggesting that Na doping using an NaF interlayer is one of the possible methods for external doping.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1625-1627
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• 2000

Cu(InGa)$Se_2$(CIGS) thin film absorbers with various Cu/(In+Ga) atomic ratios were prepared by a three-stage process using a co-evaporation appartus. The effect of Na on the structural and electrical properties of CIGS films were studied and their effects on the CIGS/Mo thin film solar cells were investigated. Soda-lime glass and Corning glass were used as substrates to compare the effect of Na diffusion into CIGS film. The resistivity of CIGS films was not changed in the Cu-poor lesion due to diffusion of Na from soda-lime glass but was mainly determined by the surface resistivity controlled by excess Na.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.182-183
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• 2006

$CuInSe_2$ single crystal thin films was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (HWE) system. The temperature dependence of the energy band gap of the $CuInSe_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)\;=\;1.1851\;eV\;-\;(8.99\;{\times}\;10^{-4}\;eV/K)T^2/(T\;+\;153K)$. After the as-grown $CuInSe_2$ single crystal thin films was annealed in Cu-, Se-, and In-atmospheres, the origin of point defects of $CuInSe_2$ single crystal thin films has been investigated by the photoluminescence(PL) at 10 K.

• 한국결정성장학회지
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• 제14권6호
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• pp.244-252
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• 2004

$CuISe_2$ 단결정 박막은 수평 전기로에서 합성한 $CuInSe_2$ 다결정을 증발원으로하여, hot wall epitaxy(HWE) 방법으로 증발원과 기판(반절연성-GaAs(100))의 온도를 각각 $620^{\circ}C$, $410^{\circ}C$로 고정하여 단결정 박막을 성장하였다. 이때 단결정 박막의 결정성은 광발광 스펙트럼과 이중결정 선 요동곡선(DCRC) 으로 부터 구하였다. Hall 효과는 van der Pauw 방법에 의해 측정되었으며, 293K에서 운반자 농도와 이동도는 각각 $9.62\times10^{16}/\textrm{cm}^3$, 296 $\textrm{cm}^2$/Vㆍs 였다. $CuAlSe_2$/Si(Semi-Insulated) GaAs(100) 단결정 박막의 광흡수와 광전류 spectra를 293k에서 10K까지 측정하였다. 광흡수 스펙트럼으로부터 band gap $E_g$(T)는 Varshni 공식에 따라 계산한 결과 1.1851 eV-($8.99\times10^{-4} eV/K)T^2$/(T+153k)였다. 광전류 스펙트럼으로 부터 Hamilton matrix(Hopfield quasicubic mode)법으로 계산한 결과 crystal field splitting Δcr값이 0.0087eV이며 spin-orbit Δso값은 0.2329 eV임을 확인하였다. 10K일 때 광전류 봉우리들은 n = 1일때 $A_1-, B_1$-와 $C_1$-exciton봉우리임을 알았다.

• Current Photovoltaic Research
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• 제3권2호
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• pp.65-70
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• 2015

We applied KF on CIGS film to modify CIGS surface with a wider-bandgap surface layer. With the KF deposition the surface of CIGS film had fine particle on the CIGS surface at 350 and $300^{\circ}C$. No fine particle was detected at 500 and $250^{\circ}C$. With the KF treatment, the Ga and O content increased at the surface, while the In and Cu content decreased. The valence band maximum was lowered with KF treatment. The composition profile and band structure were positive side of applying KF on the CIGS surface. However, the efficiency decreased with the KF treatment due to high series resistance, probably due to too thick surface layer. A smaller amount of KF should be supplied and more systematic analysis is necessary to obtain a reproducible higher efficiency CIGS solar cells.

• ETRI Journal
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• 제37권6호
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• pp.1129-1134
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• 2015

In this article, a study of a flower like nanostructured CdS buffer layer for improving the performance of a submicron-thick $CuIn_{1-x}Ga_xSe_2$ (CIGS) solar cell (SC) is presented. Both its synthesis and properties are discussed in detail. The surface reflectance of the device is dramatically decreased. SCs with flower like nanostructured CdS buffer layers enhance short-circuit current density, fill factor, and open-circuit voltage. These enhancements contribute to an increase in power conversion efficiency of about 55% on average compared to SCs that don't have a flower like nanostructured CdS buffer layer, despite them both having the same CIGS light absorbing layer.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.109-112
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• 2005

Cu계$I-III-VI_2$화합물은 직접천이형 반도체로 광흡수계수가 매우 높아 박막형 태양전지 제조에 매우 유리하다 또한 화학적으로 안정하며 Ga, A1등을 첨가하면 에너지 금지대폭을 조절할 수 있어 Wide Bandgap 태양전지 및 탠덤구조 태양전지를 제조하기에도 용이하다. $CuInSe_2(CIS)$ 물질에서 In을 $20-30\%$ 정도 치환한 $Cu(In,\;Ga)Se_2(CIGS)$ 태양전지의 경우 $19.5\%$의 세계 최고 효율을 보고하고 있으며 이는 다결정 실리콘 태양전지의 효율과 비슷한 수준이다. 본 연구에서는 동시 진공증발법을 이용하여 증착한 CIGS 박막 및 $CuGaSe_2(CGS)$ 박막을 이용하여 태양전지를 제조하였다. 공정의 재현성 및 결정립계가 큰 광흡수층 제조를 위하여 실시간 기판 온도 모니터링 시스템을 도입하였으며 버퍼층으로는 용액성장한 CdS 박막을 사용하였다. SLG/MO/CIGS(CGS)/CdS/ZnO/Al구조의 태양전지를 제조하여 면적 $0.5cm^2$에서 각각 $15\%$(CIGS)와 $7\%(CGS)$의 효율을 얻었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.99.1-99.1
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• 2010

Many efforts on the surface sulfurization of $Cu(InGa)Se_2$ (CIGS)thin films have been reported as techniques to improve CIGS solar cell performance. We have investigated the sulfurization technique using the sulfur vapor. The co-evaporated $Cu(In,Ga)Se_2$ tin film was used for sulfurization. A thin $Cu(In,Ga)(S,Se)_2$ layer was grown on the surface of the CIGS thin film after high-temperature annealing in sulfur vapor. The structural and compositional properties of the thin films were studied by XRD, EDS and AES analysis. The obtained results revealed that the surface modification technique is promising method to S incorporated into CIGS absorber.