Determination of Cu in CdTe/CdS devices before and after accelerated stress testing

Asher, S.; Hasoon, Falah S.; Gessert, T. A.; Young, Matthew R.; Sheldon, P.; Hiltner, J.; Sites, James R.

doi:10.1109/pvsc.2000.915876

Cited by 21 publications

(19 citation statements)

References 9 publications

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“…Accumulation of Cu at the CdTe/back contact interface and in the n-type CdS is observed. The Cu concentration in the polycrystalline CdTe is 5 (±3) Â 10 17 cm À 3 (see Methods), in agreement with measurements of devices in superstrate configuration 28 .…”

Section: Resultssupporting

confidence: 84%

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Doping of polycrystalline CdTe for high-efficiency solar cells on flexible metal foil

et al. 2013

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Roll-to-roll manufacturing of CdTe solar cells on flexible metal foil substrates is one of the most attractive options for low-cost photovoltaic module production. However, various efforts to grow CdTe solar cells on metal foil have resulted in low efficiencies. This is caused by the fact that the conventional device structure must be inverted, which imposes severe restrictions on device processing and consequently limits the electronic quality of the CdTe layer. Here we introduce an innovative concept for the controlled doping of the CdTe layer in the inverted device structure by means of evaporation of sub-monolayer amounts of Cu and subsequent annealing, which enables breakthrough efficiencies up to 13.6%. For the first time, CdTe solar cells on metal foil exceed the 10% efficiency threshold for industrialization. The controlled doping of CdTe with Cu leads to increased hole density, enhanced carrier lifetime and improved carrier collection in the solar cell. Our results offer new research directions for solving persistent challenges of CdTe photovoltaics.

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Section: Resultssupporting

confidence: 84%

“…Comparison of the resulting Cu distributions 28 (Fig. 3) shows that both methods lead to accumulation of Cu at the CdTe/back contact interface and in the CdS as well as a small Cu concentration in the CdTe.…”

Section: Discussionmentioning

confidence: 99%

Doping of polycrystalline CdTe for high-efficiency solar cells on flexible metal foil

et al. 2013

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“…The only quantitative SIMS analysis performed on CdTe/CdS solar cell devices from the TCO side with the glass substrate removed was mainly dedicated to the determination of Cu profile. 8 The Cu concentrations recorded in CdS were ranging from 2 ϫ 10 18 to 5 ϫ 10 19 cm −3 , i.e., about one to two orders of magnitude higher than the Cu concentrations we measured in CdS ͑3 ϫ 10 17 cm −3 , Fig. 2͒.…”

Section: Discussionmentioning

confidence: 51%

“…To overcome this difficulty, polished CdTe surfaces were used, 7 but only one SIMS analysis from the "front wall," i.e., by sputtering from the TCO to the semiconductors, has been reported. 8 This paper reports a systematic quantitative study of impurities in the window layers of CdTe/CdS/TCO/glass solar cells, this also being done with sufficient depth resolution to identify interface effects. This was achieved by dynamic and quantitative SIMS of CdTe/CdS/TCO/glass structures in the front wall geometry after the removal of the glass substrate.…”

Section: Introductionmentioning

confidence: 99%

The distribution of impurities in the interfaces and window layers of thin-film solar cells

Emziane

Durose

Halliday

et al. 2005

Journal of Applied Physics

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We report a systematic multielement study of impurities in CdS window layers by dynamic and quantitative secondary-ion-mass spectrometry (SIMS) with high depth resolution. The study was carried out on CdTe∕CdS solar cell structures, with the glass substrate removed. The analysis proceeded from the transparent conductive oxide free surface to the CdTe absorbing layer with a view to examining the influence of the CdCl2 heat treatment on the distribution and concentration of impurities in the structures. Special attention was paid to the impurities present in the CdS window layer that may be electrically active, and therefore affect the characteristics of the CdTe∕CdS device. It was shown that Cl, Na, and Sb impurities had higher concentrations in CdS following cadmium chloride (CdCl2) heat treatment while Pb, O, Sn, and Cu conserved the same concentration. Furthermore, Zn, Si, and In showed slightly lower concentrations on CdCl2 treatment. Possible explanations of these changes are discussed and the results compared with previous SIMS measurements from the “back wall” (i.e., from the CdTe free surface through the glass substrate) obtained from the same structures.

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“…Hegedus [2] and others [3][4][5][6] have shown that there are multiple modes of degradation induced by long-term light-soaking at forward bias at elevated temperatures, namely formation of a blocking contact, increased junction recombination, and increased dark resistivity. Asher [7] showed accumulation of copper in the CdS layer. This paper describes how varying the dose of copper used to form the back contact changes both initial efficiency and performance in accelerated stress testing.…”

Section: Introductionmentioning

confidence: 99%

Photovoltaic Module Reliability Workshop 2012: February 28 - March 1, 2012

Kurtz¹

2013

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Printed on paper containing at least 50% wastepaper, including 10% post consumer waste.NREL's PhotovoLtaic (Pv) ModuLE RELiabiLity WoRkshoP (PvMRW) brings together Pv reliability experts to share information, leading to the improvement of Pv module reliability. such improvement reduces the cost of solar electricity and promotes investor confidence in the technology-both critical goals for moving Pv technologies deeper into the electricity marketplace.NREL's PvMRW is unique in its requirement that all participating companies share at least one presentation (either oral or poster). in most cases, participation from each company is limited to two people. these requirements greatly increase information sharing: if everyone shares a little information, everyone takes home a lot of information.in 2012, the PvMRW included separate sessions for silicon, thin-film, and cPv in a format similar to previous workshops. the opening session highlighted the PvRessQ effort that has identified and helped to resolve many issues with older Pv systems in Japan. the silicon sessions on the first day of the workshop focused on safety issues and on potential-induced degradation.the distinguishing feature of the 2012 workshop was the addition of a day devoted to standards. this day reviewed recent work on standards development. the session "iEc 61215 on steroids" described many new tests that test labs have developed to help differentiate the durability of Pv modules. updates were given on the status and plans for task Groups 2-5 of the international Pv Module Quality assurance task Force. the afternoon provided opportunity for input from all participants, creating many lively discussions and identifying many useful suggestions for the standards being developed.on the final day of the workshop, the thin-film breakout focused on metastabilities, keeping the moisture out, and other thin-film module reliability issues. the cPv sessions highlighted accelerated testing and field experience, standards, and modeling of cPv reliability issues. in addition to the oral sessions, the participants presented approximately 80 posters on Pv reliability topics. Most of the participants shared their presentations for public posting; this document is a compilation of them. the success of the workshop is a direct result of the participants' willingness to share their results. We gratefully recognize the excellent contributions the community has made and thank all of the participants for the time and information they have shared. 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 • Grid Integration: Establishing a timely process for integrating high penetrations of solar technologies into the grid in a safe, reliable, and cost-effective manner while providing value to the system owner and the utility grid. Energy• Solar Resource: Dramatically reduce the uncertainty in solar system performance due to solar radiation measurements, and provide grid op...

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Determination of Cu in CdTe/CdS devices before and after accelerated stress testing

Cited by 21 publications

References 9 publications

Doping of polycrystalline CdTe for high-efficiency solar cells on flexible metal foil

Doping of polycrystalline CdTe for high-efficiency solar cells on flexible metal foil

The distribution of impurities in the interfaces and window layers of thin-film solar cells

Photovoltaic Module Reliability Workshop 2012: February 28 - March 1, 2012

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