Impact of Iron and Molybdenum in Mono and Multicrystalline Float-Zone Silicon Solar Cells

Coletti, Gianluca; Geerligs, L.J.; Manshanden, P.; Swanson, C. C.; Riepe, Stephan; Warta, Wilhelm; Arumughan, J.; Kopecek, Radovan

doi:10.4028/www.scientific.net/ssp.131-133.15

Cited by 10 publications

(2 citation statements)

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“…The ingot was intentionally contaminated by adding 2800 ppma of molybdenum ͑Mo͒ in the silicon melt. 15 A Mo concentration of 2 ϫ 10 13 cm −3 was determined by neutron activation analysis ͑NAA͒ on the section of the ingot studied here, as described in detail elsewhere. 15 If all of the Mo atoms are interstitial and active, this gives an upper limit to N t of 2 ϫ 10 13 cm −3 .…”

Section: Methodsmentioning

confidence: 99%

Temperature dependent carrier lifetime studies of Mo in crystalline silicon

Paudyal

McIntosh

Macdonald

et al. 2010

Journal of Applied Physics

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The capture cross sections of both electrons n and holes p were determined for interstitial molybdenum in crystalline silicon over the temperature range of Ϫ110 to 150°C. Carrier lifetime measurements were performed on molybdenum-contaminated silicon using a temperature controlled photoconductance instrument. Injection dependent lifetime spectroscopy was applied at each temperature to calculate p and n. This analysis involved a novel approach that independently determined the capture cross sections at each temperature assuming a known defect density and thermal velocity. Since the energy state is in the lower half of the bandgap, the determination of p is unaffected by the defect energy at all temperatures, and p is found to decrease with temperature in a fashion consistent with excitonic Auger capture. At temperatures below 0°C, the determination of n is also unaffected by the defect energy due to the suppression of thermal emission, and n decreases with temperature as well. It is shown that a projection of n to higher temperature suggests the defect has an energy of 0.375 eV above the valance band edge of silicon.

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Section: Methodsmentioning

confidence: 99%

Temperature dependent carrier lifetime studies of Mo in crystalline silicon

Paudyal

McIntosh

Macdonald

et al. 2010

Journal of Applied Physics

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“…Many studies report that, despite of a high level of metal contamination, similar solar cell performance can be achieved as that obtained using electronic grade purity feedstock . These studies have been carried out for a state‐of‐the‐art industrial type process for both the solar cell and the ingot growth procedures.…”

Section: Resultsmentioning

confidence: 99%

Sensitivity of state‐of‐the‐art and high efficiency crystalline silicon solar cells to metal impurities

Coletti

2012

Progress in Photovoltaics

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For the first time, the sensitivity to impurities of the solar cell conversion efficiency is reported for a state‐of‐the‐art (i.e., 18%) and advanced device architecture (i.e., 23%). The data are based on the experimental results obtained in the CrystalClear project for the state‐of‐the‐art cell process and extrapolated to a device with excellent front and rear surface passivation. Both device structures are not assumed to work in low injection level as several studies assumed before, but real operating conditions are considered. This is a fundamental difference with the past and required for modeling future high efficiency devices. The impurity with highest impact is Ti, followed by Cu, Cr, Ni and Fe, which form together a group two order of magnitude less sensitive than the former. In high efficiency devices, a large reduction of the impurity impact is visible for impurities with large capture cross‐section ratio like Fe, which reduces its relative difference in comparison with, for example, Cr, which has a small capture cross‐section ratio. In general, advanced devices will be more sensitive to the impurity content than the state‐of‐the‐art cell design. This effect is partly compensated by a reduction of the substrate thickness. The impurity sensitivity as function of the substrate thickness is reported. Copyright © 2012 John Wiley & Sons, Ltd.

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