A study on composition, structure and optical properties of copper-poor CIGS thin film deposited by sequential sputtering of CuGa/In and In/(CuGa+In) precursors

Park, Seong-Un; Sharma, Rahul; Ashok, K.; Kang, San; Sim, Jae-Kwan; Lee, Cheul-Ro

doi:10.1016/j.jcrysgro.2012.08.013

Cited by 35 publications

(14 citation statements)

References 36 publications

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“…The passivation is theorized to be a result from the drop in the valence band maximum due to a Cu‐poor stoichiometry. This acts as a hole‐repellent and thereby leads to a reduction in the recombination, and ultimately leads to improved device performance …”

Section: Resultsmentioning

confidence: 99%

Revealing Surface Modifications of Potassium‐Fluoride‐Treated Cu(In,Ga)Se₂: A Study of Material Structure, Chemistry, and Photovoltaic Performance

Aguiar

Stokes

Jiang

et al. 2016

Adv Materials Inter

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The effects of alkali post-deposition treatments and device properties for polycrystalline thin fi lm Cu(In,Ga)Se 2 have been investigated. It is reported that these surface treatments lead to differences in interface chemistry and device properties. The behavior of defects in the space charge region as a function of different growth parameters is investigated by correlative analytical microscopy. The latter combines electron microscopy based imaging, Kelvin probe force microscopy, and atom probe tomography. Alkali treatments lead to copper depletion and consequent sharpening of the compositional profi les, and the measured electric potential differences of exposed Cu(In 1-x ,Ga x )Se 2 surfaces. Measurable differences in resistivity and potential have also been observed, which are expected to relate to the improved open-circuit voltage, fi ll-factor, and device effi ciency. This study frames one perspective as to why post-deposition alkaline treatments lead to copper depletion, a mildly n-type semiconductor interface, and higher effi ciency for a Cu(In,Ga)Se 2 thin-fi lm photovoltaic device.

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Section: Resultsmentioning

confidence: 99%

Revealing Surface Modifications of Potassium‐Fluoride‐Treated Cu(In,Ga)Se₂: A Study of Material Structure, Chemistry, and Photovoltaic Performance

Aguiar

Stokes

Jiang

et al. 2016

Adv Materials Inter

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“…The hole concentration is evidently higher than the CIGS films reported by the previous studies, which show hole concentration of 10 16 ‐10 17 cm −3 . Park et al investigated the composition, structure, and optical properties of CIGS thin films fabricated by the sequential sputtering of CuGa and In targets onto the Mo‐coated soda‐lime glass and obtained the hole concentration of 10 20 ‐10 21 cm −3 orders. They attributed the higher hole concentration to the Mo back contact below the p‐type CIGS.…”

Section: Resultsmentioning

confidence: 95%

“…Note that X‐ray diffraction peak of the pre‐sintered and selenized CIGS film exhibit a highly (112) preferred orientation. The diffusion of sodium ion from soda‐lime glass substrate into CIGS absorber layer through the Mo layer lowers the surface energy of CIGS absorber during selenization, leading to the (112) preferred orientation …”

Section: Resultsmentioning

confidence: 99%

Gas‐pressure assisted sintering of copper indium gallium selenide thin films

Yang

Sun

et al. 2018

J Am Ceram Soc

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Defects, such as cracks, porous structure, small grains that easily occur in the fabrication of copper indium gallium selenide (CIGS) thin film absorbers using non‐vacuum process have been the major obstacle to practical application of this technology so far. A gas‐pressure assisted sintering process has been developed to achieve dense, crack‐free, large‐grained CIGS films. The gas‐pressure assisted sintering effects on the microstructure, crystalline, and electric properties were investigated by scanning electron microscopy, X‐ray diffraction, and Hall‐effect analyzer. A uniform microstructure with a large grain size and small amount of isolated residual pores and good electric properties can be obtained by pre‐sintering at 500°C under 6 bar N2 overpressure and then annealing at 500°C for 20 minutes under a selenium atmosphere.

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“…This is due to its high absorption coefficient, appropriate band gap and outstanding electro-optical properties [1][2][3]. CIGSbased solar cells with x = 0.3 which corresponds to a band-gap energy range of 1.1-1.2 eV yields the best efficiency both in laboratory and commercial solar cells [3].…”

Section: Introductionmentioning

confidence: 99%

Size and grain-boundary effects on the performance of polycrystalline CIGS-based solar cells

Bouchama

Rafik

Djessas³

et al. 2015

IREC2015 the Sixth International Renewable Energy Congress

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This work reviews the effect of Geometrical, physical and electrical parameters of the polycristalline CIGS thin film used as absorber materials in substrate CuIn 0.7 Ga 0.3 Se 2 (CIGS) solar cells. Two-dimensional device simulator Atlas SILVACO-TCAD was employed to study the performances of ZnO:Al/CdS/CIGS/Metal solar cell structure. The impacts of the grain sizes and the grain boundaries (GBs) in the polycrystalline p-CIGS absorber layer have been investigated. The variation of grain sizes in the CIGS bulk was studied and the corresponding design optimization was provided. The best energy conversion efficiencies have been obtained with large grain sizes higher than 2 μm for 3 μm-CIGS thick. The simulation results predict a strong detrimental effect of GBs recombination, which is enhanced by the presence of small width in the direction that attracts minority carriers. An efficiency of 17.1% (with V oc 0.68 V, J sc 34 mA/cm 2 and FF 0.77) has been achieved with small width at about 3 nm. The presence of the valence-band offset in the absorber layer is benign to solar cell performance by limit the carriers recombination. The valence-band offset is predicted to be 0.4 eV in magnitude and localized to a very thin layer at the grain surface in which the surface reconstruction takes place. All these simulation results give some important indication to lead a higher efficiency of polycrystalline CIGS solar cells for feasible fabrication.

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A study on composition, structure and optical properties of copper-poor CIGS thin film deposited by sequential sputtering of CuGa/In and In/(CuGa+In) precursors

Cited by 35 publications

References 36 publications

Revealing Surface Modifications of Potassium‐Fluoride‐Treated Cu(In,Ga)Se₂: A Study of Material Structure, Chemistry, and Photovoltaic Performance

Revealing Surface Modifications of Potassium‐Fluoride‐Treated Cu(In,Ga)Se₂: A Study of Material Structure, Chemistry, and Photovoltaic Performance

Gas‐pressure assisted sintering of copper indium gallium selenide thin films

Size and grain-boundary effects on the performance of polycrystalline CIGS-based solar cells

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A study on composition, structure and optical properties of copper-poor CIGS thin film deposited by sequential sputtering of CuGa/In and In/(CuGa+In) precursors

Cited by 35 publications

References 36 publications

Revealing Surface Modifications of Potassium‐Fluoride‐Treated Cu(In,Ga)Se2: A Study of Material Structure, Chemistry, and Photovoltaic Performance

Revealing Surface Modifications of Potassium‐Fluoride‐Treated Cu(In,Ga)Se2: A Study of Material Structure, Chemistry, and Photovoltaic Performance

Gas‐pressure assisted sintering of copper indium gallium selenide thin films

Size and grain-boundary effects on the performance of polycrystalline CIGS-based solar cells

Contact Info

Product

Resources

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Revealing Surface Modifications of Potassium‐Fluoride‐Treated Cu(In,Ga)Se₂: A Study of Material Structure, Chemistry, and Photovoltaic Performance

Revealing Surface Modifications of Potassium‐Fluoride‐Treated Cu(In,Ga)Se₂: A Study of Material Structure, Chemistry, and Photovoltaic Performance