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The effect of NaF precursors on low temperature growth of CIGS thin film solar cells on polyimide substrates
Author(s) -
Caballero Raquel,
Kaufmann Christian A.,
Eisenbarth Tobias,
Unold Thomas,
Schorr Susan,
Hesse Raik,
Klenk Reiner,
Schock HansWerner
Publication year - 2009
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200881144
Subject(s) - copper indium gallium selenide solar cells , polyimide , analytical chemistry (journal) , band gap , thin film , materials science , active layer , solar cell , quantum efficiency , thin film solar cell , diffraction , capacitance , layer (electronics) , chemistry , optoelectronics , nanotechnology , optics , thin film transistor , chromatography , physics , electrode
The aim of this work is to study the effect of Na on low temperature growth of CIGS solar cells on polyimide (PI) substrates. The Na is introduced via evaporation of a NaF precursor layer prior to the absorber deposition. As reported previously, the devices at nominal T sub,max = 500 °C are characterized by a higher V oc when the Na content increases. However, lowering process temperature to nominally 450 °C together with high Na concentration produces a pronounced band gap grading through the absorber layer, as detected by energy dispersive X‐ray spectroscopy (EDX). The absorber layers and the devices were studied by grazing incidence X‐ray diffraction, external quantum efficiency and drive level capacitance profiling. A limit T sub,max is identified as detrimental on the PV performance when high Na concentration is added, mainly due to a reduced V oc . 12.2% of efficiency (active area) is achieved reducing the Na concentration for the lower T sub,max . (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)