• Journal of the Korean institute of surface engineering
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• v.46 no.2
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• pp.61-67
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• 2013

Thin film solar cells have attracted much attention due to their high cell efficiency, comparatively low process cost, and applicability to flexible substrates. In particular, CIGS solar cells have been widely studied and produced because they demonstrated the highest cell efficiency. However, the deposition process of CIGS films generally includes the selenization process conducted at elevated temperature using toxic $H_2Se$ gas. To avoid this selenization process, CIGS thin films were, in this study, deposited by RF sputtering using single composite CIGS target. In addition, the effects of sputtering bias voltage and heat treatment on the microstructural and morphological changes in deposited CIGS films were investigated and discussed.

• Journal of the Korean Ceramic Society
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• v.48 no.4
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• pp.328-333
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• 2011

The influence of Al-doped ZnO (AZO) thin films degraded under high temperature and damp heat on the performance deterioration of Cu(In,Ga)$Se_2$ (CIGS) solar cells was investigated. CIGS solar cells with AZO/CdS/CIGS/Mo structure were prepared on glass substrate and exposed to high temperature ($85^{\circ}C$) and damp heat ($85^{\circ}C$/85% RH) for 1000 h. As-prepared CIGS solar cells had 64.91% in fill factor (FF) and 12.04% in conversion efficiency. After exposed to high temperature, CIGS solar cell had 59.14% in FF and 9.78% in efficiency, while after exposed to damp heat, it had 54.00% in FF and 8.78% in efficiency. AZO thin films in the deteriorated CIGS solar cells showed increases in resistivity up to 3.1 times and 4.4 times compared to their initial resistivity after 1000 h of high temperature and damp heat exposure, respectively. These results can be explained by the decreases in carrier concentration and mobility due to diffusion or adsorption of oxygen and moisture in AZO thin films. It can be inferred that decreases in FF and conversion efficiency were caused by an increase in series resistance, which resulted from an increase in resistivity of AZO thin films degraded under high temperature and damp heat.

• ETRI Journal
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• v.34 no.5
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• pp.779-782
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• 2012

$CuIn_{1-x}Ga_xSe_2$ (CIGS) thin films are grown on Mo/soda lime glass using a reactive sputtering process in which a Se cracker is used to deliver reactive Se molecules. The Cu and $(In_{0.7}Ga_{0.3})_2Se_3$ targets are simultaneously sputtered under the delivery of reactive Se. The effects of Se flux on film composition are investigated. The Cu/(In+Ga) composition ratio increases as the Se flux increases at a plasma power of less than 30 W for the Cu target. The (112) crystal orientation becomes dominant, and crystal grain size is larger with Se flux. The power conversion efficiency of a solar cell fabricated using an 800-nm CIGS film is 8.5%.

• Korean Journal of Materials Research
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• v.30 no.3
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• pp.131-135
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• 2020

Silver nanowire (AgNW) networks have been adopted as a front electrode in Cu(In,Ga)Se2 (CIGS) thin film solar cells due to their low cost and compatibility with the solution process. When an AgNW network is applied to a CIGS thin film solar cell, reflection loss can increase because the CdS layer, with a relatively high refractive index (n ~ 2.5 at 550 nm), is exposed to air. To resolve the issue, we apply solution-processed ZnO nanorods to the AgNW network as an anti-reflective coating. To obtain high performance of the optical and electrical properties of the ZnO nanorod and AgNW network composite, we optimize the process parameters - the spin coating of AgNWs and the concentration of zinc nitrate and hexamethylene tetramine (HMT - to fabricate ZnO nanorods. We verify that 10 mM of zinc nitrate and HMT show the lowest reflectance and 10% cell efficiency increase when applied to CIGS thin film solar cells.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.83-84
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• 2009

Thin film solar cells based on CIGS continue to be a leading candidate for thin film photovoltaic devices due to their appropriate bandgap, long-term stability, and low-cost production. To date, the most successful technique for the deposition of a CIGS absorber layer has been based on the co-evaporation However, the evaporation process is difficult to scale-up for large-area manufacturing the sputtering and Selenizaton process has been a promising method for low-cost and large-scale production of high quality CIGS In this study, we have used Cu and CuIn alloy targets for precursor deposition the precursor deposited by sputtering Cu and CuIn targets and $CuInSe_2$ thin film is manufactured by Selenization process

• Journal of Hydrogen and New Energy
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• v.24 no.4
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• pp.282-287
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• 2013

Hydrogen production from water using solar energy is attractive way to obtain clean energy resource. Among the various solar-to-hydrogen production techniques, a combination of a photovoltaic and an electrolytic cell is one of the most promising techniques in term of stability and efficiency. In this study, we show successful fabrication of precursor solution processed CIGS thin film solar cells which can generate high voltage. In addition, CIGS thin film solar cell modules producing over 2V of open circuit voltage were fabricated by connecting three single cells in series, which are applicable to water electrolysis. The operating current and voltage during water electrolysis was measured to be 4.23mA and 1.59V, respectively, and solar to hydrogen efficiency was estimated to be 3.9%.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.438-440
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• 2008

Effects of Ga contents of CIGS absorber layer on the performance of thin films solar cells were investigated. As Ga content increased, the grain size of CIGS films decreased presumably because Ga diffusion during 2nd stage of co-evaporation process is more difficult than In diffusion. Performances of corresponding solar cell show systematic dependence on Ga content in which open circuit voltage increases and short circuit current and fill factor decrease as Ga contents increases. At a optimal condition of Ga/(In+Ga)=0.27, the solar cell shows a conversion efficiency of 15.6% with $V_{OC}$ of 0.625 V, $J_{SC}$ of 35.03 mA/$cm^2$ and FF of 71.3%.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.234-234
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• 2007

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.4
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• pp.203-208
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• 2014

In this study, Sputtering method was used to grow Al-dopes ZnO films on a CIGS absorber layer, in order to examine the effect of TCO on properties of CIGS solar cell devices. Structural, electrical and optical properties were investigated by varied thickness of Al-dopes ZnO films. Also, relation to the application as a window layer in CIGS thin film solar cell were studied. It was found that the electrical and structural properties of ZnO:Al film improved with increasing its thickness. However, the optical properties degraded. Jsc of the fabricated CIGS based solar cells was significantly influenced by the variation of the ZnO:Al window layer thickness. Because ZnO:Al window layer is one of the Rs factors in CIGS solar cell. Rs has the biggest influence on efficiency characteristic. In order to obtain high efficiency of CIGS solar cell, ZnO:Al window layer should be fabricated with electrically and optically optimized.

• Current Photovoltaic Research
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• v.2 no.3
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• pp.88-94
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• 2014

The structural, optical and electrical properties of sputter-deposited CIGS films were directly influenced by the sputtering process parameters such as substrate temperature, working pressure, RF power and distance between target and substrate. CIGS thin films deposited by using a quaternary target revealed to be Se deficient due to Se low vapor pressure. This Se deficiency affected the overall stoichiometry of the films, causing the films to be Cu-rich. Current tends to pass through the Cu-Se channels which act as the shunting path increasing the film conductivity. The crystal structure of CIGS thin films depends on the substrate orientation due to the influence of surface morphology, grain size and stress of Mo substrate. The excess of Cu was removed from the CIGS films by KCN treatment, achieving a suitable Cu concentration (referred as Cu-poor) for the fabrication of solar cell. Due to high Cu concentrations on the CIGS film surface induced by Cu-Se phases after CIGS film deposition, KCN treatment proved to be necessary for the fabrication of high efficiency solar cells. Also during KCN treatment, dislocation density and lattice parameter decreased as excess Cu was removed, resulting in increase of bandgap and the decrease of conductivity of CIGS films. It was revealed that Cu-Se secondary phase could be removed by KCN wet etching of CIGS films, allowing the fabrication of high efficiency absorber layer.