The oxidation effect of a Mo back contact on Cu(In,Ga)(Se,S)  thin-film solar modules

Nam, Junggyu; Kang, Yoonmook; Kim, Dongseop; Baek, Donkyu; Lee, Dong‐Ho; Yang, JungYup

doi:10.1016/j.solmat.2015.09.035

Cited by 7 publications

(16 citation statements)

References 21 publications

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“…Many properties of molybdenum oxide with different chemical valences were studied in previous research. [ 45,46 ] Molybdenum dioxide exhibits metallic properties and has good electrical conductivity, while molybdenum trioxide demonstrates significant n‐type semiconductor characteristics with a bandgap of ≈3.2 eV. [ 47–49 ] It is widely recognized that molybdenum oxide's semiconductor characteristics are closely related to the presence of oxygen vacancies.…”

Section: Resultsmentioning

confidence: 99%

Significant Passivation Effect of Cu(In, Ga)Se₂ Solar Cells via Back Contact Surface Modification Using Oxygen Plasma

et al. 2021

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Molybdenum back contact plays a significant role in chalcopyrite Cu(In, Ga)Se2 (CIGS) solar cells. A molybdenum oxide intermediate layer is applied to optimize the back contact from the aspect of absorber crystal growth regulation and back surface field reconstruction. A novel molybdenum oxide preparation method is introduced through oxygen plasma treatment of the molybdenum layer. CIGS film is obtained by sputtering from a quaternary target with post‐selenization. The shortage of Cu and Se in the middle of the absorption layer causes crystallization stratification. A bidirectional regulation method for controlling intermediate fine grains is proposed. Superior crystallinity is produced to facilitate carriers’ transport and reduce recombination at grain boundaries. Back passivation is achieved by forming a reverse p–n junction on the back surface. Despite the formation of this reverse junction, the efficiency of the device is still improved because the transport of holes is assisted by the molybdenum oxide's gap states. Thus, back surface recombination is effectively reduced by back passivation, leading to the increase in open‐circuit voltage (Voc) and fill factor (FF). The power conversion efficiency of treated solar cells increases by 34.1%. An innovative direction is proposed to optimize the back contact of CIGS solar cells in this study.

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Section: Resultsmentioning

confidence: 99%

Significant Passivation Effect of Cu(In, Ga)Se₂ Solar Cells via Back Contact Surface Modification Using Oxygen Plasma

et al. 2021

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“…A Na‐containing layer (Na layer) as an auxiliary source for Na incorporation is deposited using commercially available 1% NaF‐doped CuGa (CuGa:NaF) sputtering targets using a high‐throughput in‐line magnetron sputtering system developed in‐house (SFA Engineering, Korea) . The system is equipped with DC power supplies and dual rotatable cathodes for plasma discharge .…”

Section: Methodsmentioning

confidence: 99%

“…In CIGSS solar cells, Na is commonly introduced by out‐diffusion from a soda‐lime glass (SLG) substrate through the Mo back contact into the CIGSS layer . However, this method is limited due to the inhomogeneous Na distribution caused by the monolithic patterning of the Mo layer . Furthermore, it is difficult to quantitatively control Na content in the absorber layer, because it is affected by various factors, including selenization parameters, the microstructure of Mo back contact, and Na compositions in the SLG substrates .…”

Section: Introductionmentioning

confidence: 99%

“…However, this method is limited due to the inhomogeneous Na distribution caused by the monolithic patterning of the Mo layer . Furthermore, it is difficult to quantitatively control Na content in the absorber layer, because it is affected by various factors, including selenization parameters, the microstructure of Mo back contact, and Na compositions in the SLG substrates . Alternatively, a variety of external Na sources have been proposed and studied for reproducible Na doping, such as vacuum deposition and posttreatment methods .…”

Section: Introductionmentioning

confidence: 99%

“…This scaling‐up issue is primarily due to large‐area inhomogeneity in the crystal quality of the CIGSS absorber layers, complicatedly depending on defects, grain boundaries, and surface/interface quality; so it is necessary to develop uniform process technologies of the absorber formation for reliable industrial‐scale production. In particular, it is important to uniformly incorporate alkali elements like sodium (Na) into the absorber layer, because they are deeply concerned with the passivation of the crystal defects and the consequential improvement in device performance …”

Section: Introductionmentioning

confidence: 99%

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Homogeneous Na incorporation for industrial‐scale application of Cu(In,Ga)(Se,S)₂ solar cells

Park¹,

Lee²,

Song³

et al. 2017

Progress in Photovoltaics

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We achieve large‐area (1602 × 902 mm2) doping uniformity without layer peel‐offs, based on a dual Na source, ie, partial Na out‐diffusion from soda‐lime glass and a homogeneously sputtered CuGa:NaF layer as an auxiliary source. We systematically investigate the optoelectronic, microstructural, and compositional characteristics of Cu(In,Ga)(Se,S)2 solar cells and analyze the underlying mechanism in detail. Na out‐diffusion from soda‐lime glass initially improves the cell performance according to the defect passivation and Na doping effects; further Na incorporation using the Na‐doped layer enhances JSC, FF, and film conductivity, which is likely due to the enhanced cell homogeneity and the alleviation of carrier transport‐limited characteristics. Excessive Na incorporation triggers the possible generation of layer peel‐offs, which is closely related to the reduced adhesion force, void generation, decrease in S/(S + Se) ratio, Ga redistribution, bandgap reduction, and increase in the low‐energy photoluminescence. These results indicate that the voids are created via Kirkendal mechanism based on the variability in atomic diffusion rates following compositional changes, resulting from the insufficiency in Na consumption or sulfurization. It is noted that an in‐line codeposition technique enables realization of high‐level Na doping as well as void‐free interface state by suppressing the defect generation, which yields high‐efficiency commercial‐scale Cu(In,Ga)(Se,S)2 modules without layer peel‐off problems.

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Review on the developments in copper indium gallium diselenide (CIGSe)-based thin film photovoltaic devices

Adhikari,

Acosta-Najarro,

Fragoso-Medina

et al. 2024

J Mater Sci: Mater Electron

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The oxidation effect of a Mo back contact on Cu(In,Ga)(Se,S) thin-film solar modules

Cited by 7 publications

References 21 publications

Significant Passivation Effect of Cu(In, Ga)Se₂ Solar Cells via Back Contact Surface Modification Using Oxygen Plasma

Significant Passivation Effect of Cu(In, Ga)Se₂ Solar Cells via Back Contact Surface Modification Using Oxygen Plasma

Homogeneous Na incorporation for industrial‐scale application of Cu(In,Ga)(Se,S)₂ solar cells

Review on the developments in copper indium gallium diselenide (CIGSe)-based thin film photovoltaic devices

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The oxidation effect of a Mo back contact on Cu(In,Ga)(Se,S) thin-film solar modules

Cited by 7 publications

References 21 publications

Significant Passivation Effect of Cu(In, Ga)Se2 Solar Cells via Back Contact Surface Modification Using Oxygen Plasma

Significant Passivation Effect of Cu(In, Ga)Se2 Solar Cells via Back Contact Surface Modification Using Oxygen Plasma

Homogeneous Na incorporation for industrial‐scale application of Cu(In,Ga)(Se,S)2 solar cells

Review on the developments in copper indium gallium diselenide (CIGSe)-based thin film photovoltaic devices

Contact Info

Product

Resources

About

Significant Passivation Effect of Cu(In, Ga)Se₂ Solar Cells via Back Contact Surface Modification Using Oxygen Plasma

Significant Passivation Effect of Cu(In, Ga)Se₂ Solar Cells via Back Contact Surface Modification Using Oxygen Plasma

Homogeneous Na incorporation for industrial‐scale application of Cu(In,Ga)(Se,S)₂ solar cells