Above 16% efficient sequentially grown Cu(In,Ga)(Se,S)<sub>2</sub>‐based solar cells with atomic layer deposited Zn(O,S) buffers

Merdes, S.; Ziem, F.; Lavrenko, Tetiana; Walter, Thomas; Lauermann, Iver; Klingsporn, Max; Schmidt, S.; Hergert, F.; Schlatmann, Rutger

doi:10.1002/pip.2579

Cited by 25 publications

(20 citation statements)

References 30 publications

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“…(i) A 60‐nm‐thick Zn(O,S) (9:1 cycle ratio of ZnO:ZnS corresponding to a [S]/([S] + [O]) of about 25%) buffer as well as a 130‐nm‐thick intrinsic ZnO (i‐ZnO) layer were deposited onto the absorber at 130 °C substrate temperature by atomic layer deposition (ALD) (Beneq TFS 500), see Refs. for details. The about 75‐nm‐thick i‐ZnO layer was deposited by ALD to avoid sputter damage to the subjacent Zn(O,S) buffer layer.…”

Section: Methodsmentioning

confidence: 99%

Adjusting the Ga grading during fast atmospheric processing of Cu(In,Ga)Se₂ solar cell absorber layers using elemental selenium vapor

Schmidt

Wolf

Rodríguez-Alvarez

et al. 2017

Progress in Photovoltaics

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We study the sequential fabrication of Cu(In,Ga)Se2 (CIGSe) absorber layers by using an atmospheric pressure selenization with a process duration of only a few minutes and the utilization of elemental selenium vapor from independent Se sources. This technology could proof to be an industrially relevant technology for the fabrication of thin‐film solar cells. Controlling the amount of Se provided during the selenization of metal precursors is shown to be an effective measure to adjust the Ga in‐depth distribution. A reduced Se supply for CIGSe formation leads to a more homogeneous Ga distribution within the absorber. The underlying growth dynamics is investigated by interrupting the selenization at different times. At first, CIGSe formation occurs in accordance with previously suggested growth paths and Ga segregates at the Mo back contact. Between 520 and 580 °C, the growth dynamics differs distinctly, and In and Ga distribute far more uniformly within the absorber depth. We also studied the impact of the precursor architecture. The best performing precursor in terms of efficiency of the respective solar cells was a multilayer with 22 In/CuGa/In triple layers. Simple bilayers stacks lead to films of higher roughness and correlated shunting. By optimizing the precursor architecture and the Ga in‐depth distribution in the CIGSe layer, a conversion efficiency of up to 15.5% (active area) could be achieved. To our knowledge, this is the highest reported efficiency for sulfur free CIGSe‐based solar cells utilizing fast (few minutes) atmospheric processes and elemental Se vapor. Copyright © 2017 John Wiley & Sons, Ltd.

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Section: Methodsmentioning

confidence: 99%

Adjusting the Ga grading during fast atmospheric processing of Cu(In,Ga)Se₂ solar cell absorber layers using elemental selenium vapor

Schmidt

Wolf

Rodríguez-Alvarez

et al. 2017

Progress in Photovoltaics

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“…1) However, η is reaching close to the performance limit. Thin-film solar cells, such as CuInGaSe2, 2,3) CdTe, 4,5) and perovskite solar cells, 6,7) have also attracted much attention in studies to realize higher-η solar cells with lower cost. However, these materials consist of critical raw materials.…”

Section: Introductionmentioning

confidence: 99%

Growth of BaSi₂ continuous films on Ge(111) by molecular beam epitaxy and fabrication of p-BaSi₂/n-Ge heterojunction solar cells

Takabe

Yachi

Tsukahara

et al. 2017

Jpn. J. Appl. Phys.

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We grew BaSi2 films on Ge(111) substrates by various growth methods based on molecular beam epitaxy (MBE). First, we attempted to form BaSi2 films directly on Ge(111) by MBE without templates. We next formed BaSi2 films using BaGe2 templates as commonly used for MBE growth of BaSi2 on Si substrates. Contrary to our prediction, the lateral growth of BaSi2 was not promoted by these two methods; BaSi2 formed not into a continuous film but into islands. Although streaky patterns of reflection high-energy electron diffraction were observed inside the growth chamber, no X-ray diffraction lines of BaSi2 were observed in samples taken out from the growth chamber. Such BaSi2 islands were easily to get oxidized. We finally attempted to form a continuous BaSi2 template layer on Ge(111) by solid phase epitaxy, that is, the deposition of amorphous Ba–Si layers onto MBE-grown BaSi2 epitaxial islands, followed by post annealing. We achieved the formation of an approximately 5-nm-thick BaSi2 continuous layer by this method. Using this BaSi2 layer as a template, we succeeded in forming a-axis-oriented 520-nm-thick BaSi2 epitaxial films on Ge substrates, although (111)-oriented Si grains were included in the grown layer. We next formed a B-doped p-BaSi2(20 nm)/n-Ge(111) heterojunction solar cell. A wide-spectrum response from 400 to 2000 nm was achieved. At an external bias voltage of 1 V, the external quantum efficiency reached as high as 60%, demonstrating the great potential of BaSi2/Ge combination. However, the efficiency of a solar cell under AM1.5 illumination was quite low (0.1%). The origin of such a low efficiency was examined.

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“…12 ZnOS then consists of stacked ZnO and ZnS layers where the S/(O + S) ratio is controlled by the number of ALD cycles used to deposit each binary layer. 3 Although the supercycle method enables a macroscopic control of film stoichiometry, microscopically it leads to out-of-plane compositional and structural nonuniformity. 13 An alternative approach to the supercycles has been proposed for the synthesis of multicomponent oxides by S-ALD, which consists of exposing an oxygen-terminated surface simultaneously to different metal-organic precursors.…”

Section: A Layer Deposition and Characterizationmentioning

confidence: 99%

“…2 Atomic layer deposition (ALD) is often used for the synthesis of Zn-based buffer layers, due to its ability to control the film composition at the atomic level and superior uniformity over nonplanar, large-area substrates with 3D topology. 3 The low deposition rate (∼0.01 nm/s) of conventional ALD can hinder the use of this technique in the solar cell industry where high throughput is needed to achieve low production costs. This drawback has been overcome by the spatial-ALD (S-ALD) technique.…”

Section: Introductionmentioning

confidence: 99%

Atmospheric spatial atomic layer deposition of ZnOS buffer layers for flexible Cu(In,Ga)Se2 solar cells

Illiberi

Frijters

Ruth

et al. 2018

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Zinc oxysulfide (ZnOS) is synthesized at atmospheric pressure in a laboratory-scale spatial atomic layer deposition setup by sequentially exposing the substrate to diethyl zinc and an H2O/H2S mixture, separated by a nitrogen gas curtain. The co-injection of H2O and H2S vapors in the same deposition zone enables an accurate control of the S/(O + S) ratio, the morphology, and the optoelectronic properties of the films. Next, the ZnOS deposition process is transferred to an industrial roll-to-roll spatial-ALD setup. ZnOS is applied as a buffer layer in flexible Cu(In,Ga)Se2 solar cells, instead of the commonly used CdS, achieving a best efficiency of typically 13% in small area cells (0.57 cm2) and 9.2% in flexible mini-modules (270 cm2). These results show the viability of atmospheric spatial-ALD as a new technique for roll-to-roll manufacturing of flexible photovoltaics modules based on a Cu(In,Ga)Se2 absorber.

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Above 16% efficient sequentially grown Cu(In,Ga)(Se,S)₂‐based solar cells with atomic layer deposited Zn(O,S) buffers

Cited by 25 publications

References 30 publications

Adjusting the Ga grading during fast atmospheric processing of Cu(In,Ga)Se₂ solar cell absorber layers using elemental selenium vapor

Adjusting the Ga grading during fast atmospheric processing of Cu(In,Ga)Se₂ solar cell absorber layers using elemental selenium vapor

Growth of BaSi₂ continuous films on Ge(111) by molecular beam epitaxy and fabrication of p-BaSi₂/n-Ge heterojunction solar cells

Atmospheric spatial atomic layer deposition of ZnOS buffer layers for flexible Cu(In,Ga)Se2 solar cells

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Above 16% efficient sequentially grown Cu(In,Ga)(Se,S)2‐based solar cells with atomic layer deposited Zn(O,S) buffers

Cited by 25 publications

References 30 publications

Adjusting the Ga grading during fast atmospheric processing of Cu(In,Ga)Se2 solar cell absorber layers using elemental selenium vapor

Adjusting the Ga grading during fast atmospheric processing of Cu(In,Ga)Se2 solar cell absorber layers using elemental selenium vapor

Growth of BaSi2 continuous films on Ge(111) by molecular beam epitaxy and fabrication of p-BaSi2/n-Ge heterojunction solar cells

Atmospheric spatial atomic layer deposition of ZnOS buffer layers for flexible Cu(In,Ga)Se2 solar cells

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Above 16% efficient sequentially grown Cu(In,Ga)(Se,S)₂‐based solar cells with atomic layer deposited Zn(O,S) buffers

Adjusting the Ga grading during fast atmospheric processing of Cu(In,Ga)Se₂ solar cell absorber layers using elemental selenium vapor

Adjusting the Ga grading during fast atmospheric processing of Cu(In,Ga)Se₂ solar cell absorber layers using elemental selenium vapor

Growth of BaSi₂ continuous films on Ge(111) by molecular beam epitaxy and fabrication of p-BaSi₂/n-Ge heterojunction solar cells