• Korean Journal of Materials Research
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• v.16 no.1
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• pp.19-24
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• 2006

ZnO:Al(AZO) films prepared by rf magnetron sputtering on glass substrate and textured by post-deposition chemical etching were applied as front contact and back reflectors for ${\mu}c$-Si:H thin film solar cells. For the front transparent electrode contact, AZO films were prepared at various working pressures and substrate temperature and then were chemically etched in diluted HCl(1%). The front AZO films deposited at low working pressure(1 mTorr) and low temperature ($240^{\circ}C$) exhibited uniform and high transmittance ($\geq$80%) and excellent electrical properties. The solar cells were optimized in terms of optical and electrical properties to demonstrate a high short-circuit current.

• Korean Journal of Materials Research
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• v.18 no.6
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• pp.294-297
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• 2008

In this paper, a novel non-vacuum technique is described for the fabrication of a $CuInSe_2$ (CIS) absorber layer for thin film solar cells using a low-cost precursor solution. A solution containing Cu- and Inrelated chemicals was coated onto a Mo/glass substrate using the Doctor blade method and the precursor layer was then selenized in an evaporation chamber. The precursor layer was found to be composed of CuCl crystals and amorphous In compound, which were completely converted to chalcopyrite CIS phase by the selenization process. Morphological, crystallographic and compositional analyses were performed at each step of the fabrication process by SEM, XRD and EDS, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.454-454
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• 2010

In order to achieve a high efficient a-Si solar cell, the TCO (transparent conductive oxide) substrates are required to be a low sheet resistivity, a high transparency, and a textured surface with light trapping effect. Recently, a zinc oxide (ZnO) thin film attracts our attention as new coating material having a good transparent and conductive for TCO of solar cells. In this paper the optical properties of $H_2$ post-treated BZO (boron doped ZnO, ZnO:B) thin film are investigated with $O_2$-plasma treatment. The BZO thin films by MOCVD (Metal Organic Chemical Vapor Deposition) are investigated and the samples of $H_2$ post-treated BZO thin film are tested with $O_2$-plasma treatment by plasma treatment system with 13.56 MHz as RIE (Reactive Ion Etching) type. We measured the optical properties and surface morphology of BZO thin film with and without $O_2$-plasma treatment. The optical properties such as transmittance, reflectance and haze are measured with integrating sphere and ellipsometer. This result of the BZO thin film with and without $O_2$-plasma treatment is application to the TCO for solar cells.

• New & Renewable Energy
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• v.2 no.3
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• pp.31-36
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• 2006

Superstrate pin amorphous silicon thin-film(a-Si:H) solar cells are prepared on $SnO_2:F$ and ZnO:Al transparent conducting oxides(TCO) in order to see the effect of TCO/p-layers on a-Si:H solar cell operation. The solar cells prepared on textured ZnO:Al have higher open circuit voltage VOC than cells prepared on $SnO_2:F$. Presence of thin microcrystalline p-type silicon layer(${\mu}c-Si:H$) between ZnO:Al and p a-SiC:H plays a major role by causing improvement in fill factor as well as $V_{OC}$ of a-Si:H solar cells prepared on ZnO:Al TCO. Without any treatment of pi interface, we could obtain high $V_{OC}$ of 994mV while keeping fill factor(72.7%) and short circuit current density $J_{SC}$ at the same level as for the cells on $SnO_2:F$ TCO. This high $V_{OC}$ value can be attributed to modification in the current transport in this region due to creation of a potential barrier.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.158-161
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• 2006

Superstrate pin amorphous silicon thin-film (a-Si:H) solar cells are prepared on $SnO_2:F$ and ZnO:Al transparent conducting oxides (TCO) In order to see the effect of TCO/P-layers on a-Si:H solar cell operation. The solar cells prepared on textured ZnO:Al have higher open circuit voltage $V_{oc}$ than cells prepared on $SnO_2:F$. Presence of thin microcrystalline p-type silicon layer $({\mu}c-Si:H)$ between ZnO:Al and p a-SiC:H plays a major role by causing improvement in fill factor as well as $V_{oc}$, of a-Si:H solar cells prepared on ZnO:Al TCO. Without any treatment of pi interface, we could obtain high $V_{oc}$, of 994mv while keeping fill factor (72.7%) and short circuit current density $J_{sc}$ at the same level as for the cells on $SnO_2:F$ TCO. This high $V_{oc}$ value can be attributed to modification in the current transport in this region due to creation of a potential barrier.

• Journal of the Korean Electrochemical Society
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• v.14 no.2
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• pp.61-70
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• 2011

Thin film solar cells with chalcopyrite $CuInSe_2/Cu(In,Ga)Se_2$ absorber materials, commonly known as "CIS/CIGS solar cells" have recently attracted significant research interest as a potential alternative energy-harvesting system for the next generation. Among the different deposition techniques available for the CIGS absorber layer, electrodeposition is an effective and low cost alternative to vacuum based deposition methods. This article reviews progress in the area of CIGS solar cells with an emphasis on electrodeposited absorber layer. Existing challenges in fabrication of stoichiometric absorber layer are highlighted.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.97-97
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• 2014

The properties of thin film solar cells based on electrodeposited $CuIn(Se,S)_2$ were investigated. The proposed solar cell fabrication method involves a single-step $CuInSe_2$ thin film electrodeposition followed by sulfurization in a tube furnace to form a $CuIn(Se,S)_2$ quaternary phase. A sulfurization temperature of $450-550^{\circ}C$ significantly affected the performance of the $CuIn(Se,S)_2$ thin film solar cell in addition to its composition, grain size and bandgap. Sulfur(S) substituted for selenium(Se) at increasing rates with higher sulfurization temperature, which resulted in an increase in overall band gap of the $CuIn(Se,S)_2$ thin film. The highest conversion efficiency of 3.12% under airmass(AM) 1.5 illumination was obtained from the $500^{\circ}C$-sulfurized solar cell. The highest External Quantum Efficiency(EQE) was also observed at the sulfurization temperature of $500^{\circ}C$.

• Current Photovoltaic Research
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• v.2 no.3
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• pp.95-102
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• 2014

Light trapping techniques can change the propagation direction of incident light and keep the light longer in the absorption layers of solar cells to enhance the power conversion efficiency. In thin film silicon (Si) solar cells, the thickness of absorption layer is generally not enough to absorb entire available photons because of short carrier life time, and light induced degradation effect, which can be compensated by the light trapping techniques. These techniques have been adopted as textured transparent conduction oxide (TCO) layers randomly or periodically textured, intermediate reflection layers of tandem and triple junction, and glass substrates etched by various patterning methods. We reviewed the light trapping techniques for thin film Si solar cells and mainly focused on the commercially available techniques applicable to textured TCO on patterned glass substrates. We described the characterization methods representing the light trapping effects, texturing of TCO and showed the results of multi-scale textured TCO on etched glass substrates. These methods can be used tandem and triple thin film Si solar cells to enhance photo-current and power conversion efficiency of long term stability.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.158-158
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• 2011

$Cu(In_xGa_{1-x})Se_2$ (CIGS) thin film solar cell is one of the most promising solar cells in photovoltaic devices. CIGS has a direct band gap which varied from 1.0 to 1.26 eV, depending on the Ga to In ratio. Also, CIGS has been studying for an absorber in thin film solar cells due to their highest absorption coefficient which is $1{\times}10^5cm^{-1}$ and good stability for deposition process at high temperature of $450{\sim}590^{\circ}C$. Currently, the highest efficiency of CIGS thin film solar cell is approximately 20.3%, which is closely approaching to the efficiency of poly-silicon solar cell. The deposition technique is one of the most important points in preparing CIGS thin film solar cells. Among the various deposition techniques, the sputtering is known to be very effective and feasible process for mass production. In this study, CIGS thin films have been prepared by rf magnetron sputtering method using a single target. The optical and structural properties of CIGS films are generally dependent on deposition parameters. Therefore, we will explore the influence of deposition power on the properties of CIGS films and the films will be deposited by rf magnetron sputtering using CIGS single target on Mo coated soda lime glass at $500^{\circ}C$. The thickness of CIGS films will be measured by Tencor-P1 profiler. The optical properties will be measured by UV-visible spectroscopy. The crystal structure will be analyzed using X-ray diffraction (XRD). Finally the optimal deposition conditions for CIGS thin films will be developed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.267-267
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• 2009

Solar cells with CIGS absorber layers have proven their suitability for high efficiency and stable low cost solar cells. We prepared and characterized particle based CIGS thin film using a non-vacuum processing. CIGS powder were obtained at $240^{\circ}C$ for 6 hours from the reaction of $CuCl_2$, $InCl_3$, $GaCl_3$, Se powder in solvent. The nanoparticle precursors were mixed with binder material. The CIGS thin film deposited on a sodalime glass. The CIGS thin film were identified to have a typical chalcopyrite tetragonal structure by using UV/Visible-spectroscopy, X-ray diffraction(XRD), Auger Electron Spectroscopy(AES), Scanning Electron Microscopy(SEM).