Open AccessRear Contact Passivation for High Bandgap Cu(In, Ga)Se2 Solar Cells With a Flat Ga profile
Author(s) -
Dorothea Ledinek,
Pedro Salome,
Carl Hagglund,
Uwe Zimmermann,
Marika Edoff
Publication year - 2018
Publication title -
ieee journal of photovoltaics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.023
H-Index - 72
eISSN - 2156-3403
pISSN - 2156-3381
DOI - 10.1109/jphotov.2018.2813259
Subject(s) - photonics and electrooptics
In this study, Cu(In, Ga)Se2 solar cells with a high bandgap (1.31 eV) and a flat Ga profile ([Ga]/([Ga]+[In]) ≈ 0.60) were examined. For absorber layer thicknesses varying from 0.60 to 1.45 μm, the Mo rear contact of one set of samples was passivated with an ultrathin (27 nm) Al2O3 layer with point contact openings, and compared with reference samples where the rear contact remained unpassivated. For the passivated samples, mainly large gains in the short-circuit current led to an up to 21% (relative) higher power conversion efficiency compared with unpassivated cells. The differences in temperature-dependent current voltage behavior between the passivated and the unpassivated samples and the thin and the thick samples can be explained by an oppositely poled secondary photodiode at the rear contact.