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Passivation at the interface between liquid‐phase crystallized silicon and silicon oxynitride in thin film solar cells
Author(s) -
Preissler Natalie,
Töfflinger Jan Amaru,
Gabriel Onno,
Sonntag Paul,
Amkreutz Daniel,
Stannowski Bernd,
Rech Bernd,
Schlatmann Rutger
Publication year - 2017
Publication title -
progress in photovoltaics: research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.286
H-Index - 131
eISSN - 1099-159X
pISSN - 1062-7995
DOI - 10.1002/pip.2852
Subject(s) - passivation , materials science , dielectric , silicon , solar cell , quantum efficiency , analytical chemistry (journal) , hydrogen , optoelectronics , layer (electronics) , nanotechnology , chemistry , chromatography , organic chemistry
The passivation quality at the interface between liquid‐phase crystallized silicon (LPC‐Si) and a dielectric interlayer (IL) was investigated in terms of the defect state density at the IL/LPC‐Si interface ( D it ) as well as the effective fixed charge density in the IL ( Q IL,eff ). Both parameters were obtained via high‐frequency capacitance–voltage measurements on developed metal–insulator–semiconductor structures based on a molybdenum layer sandwiched between the IL and the glass substrate. D it and Q IL,eff were correlated to the open circuit voltage ( V oc ) and the integrated external quantum efficiency ( J sc,EQE ) obtained on corresponding solar cell structures as well as to V oc and J sc,EQE results based on two‐dimensional simulations. We found that D it was reduced by one order of magnitude using a hydrogen plasma treatment (HPT) at 400 °C. Irrespectively of the HPT, Q IL,eff was > 10 12 cm −2 . We suggest that field‐effect passivation dominates chemical passivation at the IL/n‐type LPC‐Si interface. We attribute the significant enhancement of V oc and J sc,EQE observed after HPT on n‐type LPC‐Si solar cells mainly to improvements of the passivation quality in the n‐type LPC‐Si bulk rather than at the IL/n‐type LPC‐Si interface. For p‐type absorbers, the HPT did not improve V oc and J sc,EQE significantly. We propose that this is because of an insufficient passivation of bulk defects by positively charged hydrogen, which dominates in p‐type silicon, in combination with an insufficient interface passivation. Copyright © 2016 John Wiley & Sons, Ltd.