Comparison of ZnO:B and ZnO:Al layers for Cu(In,Ga)Se2 submodules

Koida, Takashi; Nishinaga, Jiro; Higuchi, Hirohumi; Kurokawa, A.; Iioka, Masayuki; Kamikawa, Yukiko; Yamada, A.; Shibata, Hajime; Niki, Shigeru

doi:10.1016/j.tsf.2016.03.004

Cited by 19 publications

(20 citation statements)

References 18 publications

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“…O 2 /(Ar + O 2 ) flow ratios were 1% and 0.4% during ZnO and ZnO:Al deposition, respectively. Layers of 1.8‐μm‐thick ZnO:B were deposited at 160°C and 170°C via MOCVD using diethylzinc, water, and diborane with flow rates of 100, 200, and 0.2 μmol minute −1 , respectively . A 50‐nm‐thick a ‐IGZO layer was deposited with no intentional substrate heating via rf magnetron sputtering deposition using an In‐Ga‐Zn‐O (In:Zn:Ga = 1:1:1) ceramic target with an O 2 /(Ar + O 2 ) flow ratio of 0.08%.…”

Section: Methodsmentioning

confidence: 99%

“…The O 2 /(Ar + O 2 ) flow ratios were 24% for 50 and 70‐nm‐thick films and 30% for 150‐nm‐thick films. The electrical properties of the TOS and TCO films are described elsewhere . The sheet resistance of ZnO:Al, ZnO:B (160°C), ZnO:B (170°C), a ‐In 2 O 3 :H (50 nm), a ‐In 2 O 3 :H (70 nm), and a ‐In 2 O 3 :H (150 nm) grown on SLG was 39, 19, 15, 69, 51, and 27 Ω sq −1 , respectively.…”

Section: Methodsmentioning

confidence: 99%

“…The sheet resistance of ZnO:Al, ZnO:B (160°C), ZnO:B (170°C), a ‐In 2 O 3 :H (50 nm), a ‐In 2 O 3 :H (70 nm), and a ‐In 2 O 3 :H (150 nm) grown on SLG was 39, 19, 15, 69, 51, and 27 Ω sq −1 , respectively. Figure shows optical constants (refractive index [ n ] and extinction coefficient [ k ]) of the TOS and TCO layers evaluated from spectroscopic ellipsometry . To evaluate the optical constants, the TOS and TCO layers were deposited on SiO 2 ‐coated Si.…”

Section: Methodsmentioning

confidence: 99%

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Impact of front contact layers on performance of Cu(In,Ga)Se₂ solar cells in relaxed and metastable states

Koida

Nishinaga

Ueno

et al. 2018

Progress in Photovoltaics

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We studied the impacts of front contact layers composed of transparent conducting oxide (TCO) and transparent oxide semiconductor (TOS) layers on the performance of Cu(In,Ga)Se 2 (CIGS) solar cells with glass/Mo/CIGS/CdS/TOS/TCO in relaxed and metastable states. After annealing under illumination, the CIGS solar cells with KF and NaF postdeposition treatments exhibited metastable increases in open-circuit voltage, fill factor, and the resulting conversion efficiency with a metastable decrease in short-circuit current density. These are partly attributed to an increase in metastable acceptor density in the CIGS layers, being stable for a day even at room temperature, with a reduced space charge width. We found that the net acceptor density evaluated by capacitance-voltage measurements largely varied depending on the TOS/TCO layers, whereas the open-circuit voltage was identical. On the other hand, no significant differences in both the net acceptor density and open-circuit voltage were observed regardless of the TOS/TCO layers in the relaxed state produced by annealing in the dark. The results suggest that the CdS/CIGS heterojunction can no longer be treated as an n + /p junction in the metastable state and that the evaluated acceptor density was apparent values with large difference originating from different potential distribution in the CdS layer, which is related to the TOS/CdS and TCO/CdS junctions. In addition, the TOS/TCO layers largely affected the short-circuit current density owing to their optical constants and film thicknesses. The presented results highlight the importance of the design of CdS/TOS/TCO layers in solar cells operated in metastable states.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Impact of front contact layers on performance of Cu(In,Ga)Se₂ solar cells in relaxed and metastable states

Koida

Nishinaga

Ueno

et al. 2018

Progress in Photovoltaics

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“…can be compared. It was shown before, that by exchanging ZnO:Al with a ZnO:B TCO, the short circuit current density J SC can be increased, 9 while for In 2 O 3 :H an improved J SC and V oc was observed. 10 However, these studies were conducted on CIGSe solar cells, which were not subjected to a KF-PDT step during processing.…”

Section: Introductionmentioning

confidence: 90%

“…Three TCOs are investigated here: (1) sputtered i‐ZnO/ZnO:Al (reference), (2) chemical vapor deposited (CVD) ZnO:B, and (3) sputtered In 2 O 3 :H. In this way, a change in deposition method as well as a change in material system can be compared. It was shown before, that by exchanging ZnO:Al with a ZnO:B TCO, the short circuit current density J SC can be increased, while for In 2 O 3 :H an improved J SC and V oc was observed . However, these studies were conducted on CIGSe solar cells, which were not subjected to a KF‐PDT step during processing.…”

Section: Introductionmentioning

confidence: 99%

Effect of KF absorber treatment on the functionality of different transparent conductive oxide layers in CIGSe solar cells

Keller

Chalvet

Joel

et al. 2017

Progress in Photovoltaics

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Si‐Doped Cu(In,Ga)Se₂ Photovoltaic Devices with Energy Conversion Efficiencies Exceeding 16.5% without a Buffer Layer

Ishizuka

Nishinaga

Iioka

et al. 2018

Advanced Energy Materials

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In this communication, novel and simplified structure Cu(In,Ga)Se2 (CIGS) solar cells, which nominally consist of only a CIGS photoabsorber layer sandwiched between back and front contact layers but yet demonstrate high photovoltaic efficiencies, are reported. To realize this accomplishment, Si‐doped CIGS films grown by the three‐stage coevaporation method, B‐doped ZnO transparent conductive oxide front contact layers deposited by chemical vapor deposition, and heat–light soaking treatments are used. Si‐doping of CIGS films is found to modify the film surfaces and grain boundary properties and also affect the alkali metal distribution profiles in CIGS films. These effects are expected to contribute to improvements in buffer‐free CIGS device performance. Heat–light soaking treatments, which are occasionally performed to improve conventional buffer‐based CIGS device performance, are found to be also effective in enhancing buffer‐free CIGS photovoltaic efficiencies. This result suggests that the mechanism behind the beneficial effects of heat–light soaking treatments originates from CIGS bulk issues and is independent of the buffer materials. Consequently, over 16.5% efficiencies, including an independently certified value, are demonstrated from completely buffer‐free CIGS photovoltaic devices.

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Comparison of ZnO:B and ZnO:Al layers for Cu(In,Ga)Se2 submodules

Cited by 19 publications

References 18 publications

Impact of front contact layers on performance of Cu(In,Ga)Se₂ solar cells in relaxed and metastable states

Impact of front contact layers on performance of Cu(In,Ga)Se₂ solar cells in relaxed and metastable states

Effect of KF absorber treatment on the functionality of different transparent conductive oxide layers in CIGSe solar cells

Si‐Doped Cu(In,Ga)Se₂ Photovoltaic Devices with Energy Conversion Efficiencies Exceeding 16.5% without a Buffer Layer

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Comparison of ZnO:B and ZnO:Al layers for Cu(In,Ga)Se2 submodules

Cited by 19 publications

References 18 publications

Impact of front contact layers on performance of Cu(In,Ga)Se2 solar cells in relaxed and metastable states

Impact of front contact layers on performance of Cu(In,Ga)Se2 solar cells in relaxed and metastable states

Effect of KF absorber treatment on the functionality of different transparent conductive oxide layers in CIGSe solar cells

Si‐Doped Cu(In,Ga)Se2 Photovoltaic Devices with Energy Conversion Efficiencies Exceeding 16.5% without a Buffer Layer

Contact Info

Product

Resources

About

Impact of front contact layers on performance of Cu(In,Ga)Se₂ solar cells in relaxed and metastable states

Impact of front contact layers on performance of Cu(In,Ga)Se₂ solar cells in relaxed and metastable states

Si‐Doped Cu(In,Ga)Se₂ Photovoltaic Devices with Energy Conversion Efficiencies Exceeding 16.5% without a Buffer Layer